Announcement

**Fair!** · 12-26-2025, 06:03 PM

continued from above

QUICK PROGRESS WITH S65 SWAP

Now that we had the S65 engine from the E36 M3, and the best parts of the red 328, it was time to put them all together on the black 330 and truly begin our E46 M3 GTR tribute / SCCA Max4 race car build.

On the same day that Brad finished stripping the red 328 of the widebody parts (all except the bonded on rear flares, which we have a plan for) the Flossmann front fenders were being installed onto the black 330. Things were moving rapidly, especially considering we had FIVE other shop builds that were gobbling up time and resources, including two other NEW builds getting engine swaps (the red FRS and white Fox Mustang shown above).

Later that day I made this video above, which explains my reasoning behind doing this E46 chassis instead of pushing the S65 into the E36 M3. Most people agree that this E46 chassis makes a lot more sense, considering the extensive weight removal and proper roll cage it has.

Over the next two days Brad worked on the the black 330 chassis fitting the Flossman front bodywork, then starting on the roof swap. The black 330 had a steel roof and sunroof panel delete kit, but we felt like there was another 20 pounds to lose if we did the carbon roof swap - just like the BMW E46 CSL had from the factory, we will use 3M panel body to adhere this to the chassis.

After a few weeks of searching (during the E36 M3 phase of this swap), I finally found a proper DCT from a 2012 BMW E92 M3 across town for a good price on December 11. The reason I bought this particular DCT was because the salvage yard ALSO had the factory "DME" (engine computer) from the same car. They sold me the DME, two body modules, key reader and key - so theoretically we could have bought the chassis harness from this same car and make it all work. This means the DME is "married" to this DCT, which makes the swap easier.

Instead of using a stock harness, we're going to buy a stand-alone harness from Randy at EPIC Motorsports to control the engine + DCT transmission, and we won't need the key reader. That simplifies the swap and allows the DME to be reprogrammed but keep the factory refinement of transmission and engine control.

By December 12th we had the drivetrain in the car, and our E46 "GTR" build was well underway, as shown in this Dec 12th video. In the days since we have built drivetrain mounts, ordered parts to make the driveshaft and long tube headers, sent the DME to Randy at EPIC for his tune and stand-alone harness, and this E46 GTR build is truly going at Warp Speed.

EXPLAINING SCCA MAX CLASSES + SAFETY PREP LEVELS

This is the last section of this thread, which explains the CLASS RULES CONSTRAINTS we have to build around. Before you start offering up crazy engine upgrades, know this - we are building this for SCCA Time Trial Max category class 4 (Max4), and we will ensure that the car will be 100% legal. That series has some pretty austere limits on what you can do to an engine in the lower classes (there are 5 Max classes, with Max1 being the fastest / wildest), and we're building for an "unmodified" engine swap (the long block has to remain stock, but intake / exhaust / oil pan and water pump are open).

We ran the E36 M3 in Max 5 class in 2025 (slowest Max class), and Max4 is only one jump up from that. We're gong to Max4 because it has LIMITS on engine mods and power levels, which will save money on the drivetrain, save on consumables, and save on the overall build. The virtually unlimited allowance Max1 class build on my S550 Mustang (shown below right) will have cost more than 3 or 4 of these Max4 / Max5 cars would!

Let's back up and explain the 5 Max classes and 3 safety levels we can build around.

Left: A "Tuner 3" class prepped 2023 BRZ. 18x10" wheels, MCS, race seats. Right: Max1 prepped Mustang will full aero, 200TW tires, swapped engine

SCCA Time Trial has 4 categories of classes: Sport, Tuner, Max and Unlimited. We've built for Tuner, Max and Unlimited classes, and Max seems to be the sweet sport for "builders" and shops like us - we can go "all out" on the suspension, drivetrain swaps are relatively unlimited, and you can add some functional aero, all with 200TW tires as the tire limit (but currently no tire width limit in any Max class).

SCCA TT Max Rules: Link

As I have seen first hand, Tuner classes are generally cheaper to prep for "to the limit" than Max, but you need a relatively new car to be competitive in Tuner. We had good luck with a 2006 C6 Corvette, but we had to really lean on it to keep up with newer cars in T2 cars at the time. Our 2024 Darkhorse was a faster car in T2 and relatively mild build. My dream Tuner class build is a T1 classed C8 Corvette - we'll see if 2026 goes well and I can score a good C8 Z51 to start with for that suspension development mule / Tuner build.

Max levels the playing field with enough additional mods so that you can make anything fast - old or new, obscure junk to factory sports car. The spending goes up as well, but a fast Tuner car is often quicker than the typical Max3-Max5 cars. It just comes down to power-to-weight ratios, as it is often tough to make minimum eight in Max classes, and most folks are scared of engine swaps.

Our Max4 E46 build here should be below min weight (so we can ballast) and with roughly 400 whp from an uncorked S65 V8 + DCT, it should be quicker than any of our previous Tuner builds. Will it be faster than a hopped up Supra or C8 in Tuner 1? I guess we will see next season!

SCCA TT Safety Rules: Link

There are also 3 options for "levels of Safety" you can choose for your car in all SCCA time Trial classes. Level 1 Safety is stock 3-point belts and stock seats. You need ALL of the interior in a Max car with Level 1, plus a proper helmet. That's it.

If you go for Level 2 Safety (see above - our E36 M3 above left, our E46 330 above right) you need a properly built 4-point roll bar, and fixed racing seats 5+ point belts. Level 2 safety then allows you to gut the interior behind the roll bar. But you still need a headliner (ahead of the main hoop), interior panels, carpets (from the front seats forward), door panels, windows, dash, and a heater + wipers.

There can be alternate materials used on the required interior bits - read this thread for more ideas on that. We have taken our Max5 prepped 1995 M3 to the limits of Level 2 Safety material replacements, but it was still 550 pounds heavy for Max5. That min weight just wasn't realistic for the E36.

Level 3 safety (see above) is a fully caged car (that meets SCCA or NASA Club Racing specs) and if the cage "goes into the doors" you can gut the doors, remove the door window glass. Like with all W2W race cars, Level 3 only requires the driver's seat. Level 3 cars can also remove ALL of the interior carpets, fabrics, and plastics - except the dash (but it ca be alternate materials or lightened).

Level 3 is a much safer, of course, but a considerably more expensive level of safety to build. It can with the right planning allow for a lighter overall car. This level is never a real "street car", but it is allowed for those that can tow their race cars to events and want the ultimate in safety on track. As of November of 2025 (See FasTrack image above), Level 3 cars can now replace the rear door/quarter windows and back window with 3mm or thicker Lexan / Polycarbonate. That saves roughly half the weight of the tempered glass.

I wrote the letter asking for this back in June to be legal to run in SCCA Max as Level 3 Safety cars. And also because my Max1 already car had Lexan, and it was legal in Max up through 2024. This rules change was the last piece of the puzzle that made our E46 "team car" legal for Max, and also now allows so many W2W cars into Max category Time Trial. Hopefully that quick and dirty explanation of Max classes and Safety Levels will makes sense.

HOW THE S65 4.0L V8 FITS INTO MAX4

Each of the Max category classes have "formulas" for engine both NA and boosted displacements, associated minimum weights, and even modified vs unmodified engines. The most attractive (and cheapest) Max classes to run are Max4 and Max5 classes. The formulas for both are shown below. Remember that weights INCLUDE the driver, and my 200 pounds needs to be added to the chassis weight to reach the total minimum weight.

That "2550" pound minimum weight for Max5 with the "up to 3.0L" engine formula was impossible for the E36 M3, as that would mean 2350 pounds plus my body weight. This is why Max4 looked so much more appealing - with the "A" formula for 3.7-4.5L unmodified engines having a 3000 pound minimum weight. Could we have made the 2700 pound min weight for the "B" formula? Probably, but we already have a 3.7L swapped FRS using this "B" formula in my wife's 2013 FRS.

With the full roll cage and Level 3 Safety in our E46 chassis, the 4.0L engine fits nicely in the "A" formula for Max4 - we could not find a more powerful "unmodified" engine up to 4.5L that wasn't 3x the cost (some exotic engines). There is no penalty for the DCT transmission in this class, other than the extra weight it adds over a true manual transmission roughly +80 lbs). We have not seen this S65 + DCT swap done in SCCA MAx4, so that will be a first. And from early weight checks we're going to easily end up well under the 3000 lb min weight - so much so that we are planning a large amount of ballast, and where to put it.

And yes, we've cleared all of this build and the S65 + DCT swap with the "powers that be" within SCCA Time Trial - they know the details of this build, and are actually excited to see a more developed Max4 build like this. I post updates daily on this build on my Facebook page as well as regular updates to the SCCA Time Trials MAX Track Builds facebook group. We aren't hiding anything.

WHAT'S NEXT?

We're much further along than this post shows, but I need to wrap up this introductory post and let you folks digest the reasoning, the rules, all 3 builds merged into one, and the early progress of this build.

The next post in this thread will show the S65 + DCT drivetrain mounts, more "progress" weights on the chassis, parts weights like the 11.8 pound carbon doors, and details about the Prius EPAS column. I've got a ton of parts that have arrived for the paddle shifters, new steering wheel and QR hub, and the race seat should be back in the car next week. We have an E46 M3 driveshaft to modify to fit the DCT output flange, modifications to the S65 oil pan to show, new valve covers, DTM style side mirrors, and more.

Thanks for reading!

**Fair!** · 02-13-2026, 12:40 PM

Project Update - Feb 13, 2026: Our BMW E46 GTR clone / SCCA Max 4 build is coming along nicely, and I started writing this post 10 days ago. We have done a good bit of work over the last 8 weeks on this ambitious, time crunch of a project. As always we will dive deep into the technical details, the "Hows" and "Whys" of parts selection and fabrication. Every image can be clicked for a higher resolution version or video.

For those with short attention spans, I've made a 5 minute video that shows the work done that is detailed in this post up through Feb 2, 2026 - quick and dirty and almost as current as this 5-part forum post.

In this post will jump back in time to November 2025, when we first located this S65 engine - when it was for the perfectly good E36 M3 we almost hacked up. That red E36 was a very nice race car and I really liked a lot of aspects of that, many of which we are applying to this E46. Things like the same level of aero, MCS dampers, 315mm A052 tires, and widebody fenders. The S65 is just as desirable for this E46 chassis.

That 246 whp 1995 M3 is currently for sale, as is our 700 whp 2015 Mustang Time Attack car. Why sell both of our existing race cars? Space. Money. Distraction. For business reasons we have to change up our race cars every 1-3 years, as we run out of parts to develop, which we do to help sell parts. That's the real purpose behind ALL of our builds, well and they are also fun to create and race. But let's step back explain why this S65 engine is desirable.

WHAT'S SO SPECIAL ABOUT THE S65 ENGINE?

If you don't know about the BMW S65 4.0L V8, don't fret. Maybe you live under a rock, maybe you have never had the pleasure of driving the 2008-14 BMW E9X generation M3. Long story short: BMW wanted to step up their game, so they shoved a bunch of BMW F1 engineers into a laboratory and they came out with the S65 V8 and S85 V10.

The M3 model of the E90/E92/E93 3 Series range was powered by the BMW S65 V8 engine and was produced in four door sedan, convertible and coupe body styles. The E9x is the first and only standard production M3 powered by a V8 engine as its successor would revert to using a straight 6 engine. In the standard M3, the S65 engine rated at 414 hp at 8,400 rpm and 295 lb⋅ft at 3,900 rpm. Initially, the M3 was produced with a 6-speed manual transmission. In April 2008, the E90/E92/E93 M3 became the first BMW to be available with a dual-clutch transmission when the 7-speed Getrag "M-DCT" transmission was introduced as an option.

The E90 and E92 versions received many positive reviews, including "the greatest all-around car in the world", "the finest car on the market, period" and "the best, most complete car in the world". It was not an inexpensive car with fully optioned 2008 M3 coupes reaching over $72,000.Total production of the E9x M3 was 40,092 coupes, 16,219 convertibles and 9,674 four door sedans. Production of sedan models finished in 2011, with coupes remaining in production until July 5, 2013.

The chassis was a great handling package but they were also heavier than the E46, with the V8 and all the kit topping 3600 pound curb weights. Yes, that's what a Mustang weighs from that period. What made these models so exceptional was the high revving V8 and optional 7 speed Dual Clutch sequential transmission. Having driven a number of DCT equipped cars on track, there is nothing quite like it.

The BMW S65 is a naturally aspirated V8 engine which was produced from 2007 to 2013. There is no direct replacement for the S65, since the following generation of M3 switched to a turbocharged straight-six engine (the BMW S55). Derived from the BMW S85 V10 engine (as used in the E60 M5), the S65 shares the same basic architecture and aluminum construction. Unlike most other BMW M engines, the S65 and S85 are not related to a regular production BMW engine. The S65 won the International Engine of the Year award for the 3.0 to 4.0 L category in 2008, 2009, 2010, 2011 and 2012.

The S65 shares the same cylinder dimensions with the S85 V10, with a 92 mm (3.6 in) bore and a 75.2 mm (3.0 in) stroke. Other common features include individual throttle bodies, double-VANOS (variable valve timing) and the 12.0:1 compression ratio. The redline is 8,400 rpm. To reduce weight, a wet-sump lubrication system with two electrically operated scavenging pumps and a main oil pump replaces the three-pump wet-sump system used on the S85. The S65 weighs 445 lb, which is 33 lb less than the E46 M3's S54 straight-6 predecessor.

When this engine came out I was personally buried in the GM LS V8 world, then later the 5.0L Coyote V8s. I didn't look at the 4.0L S65 with anything but scorn, but eventually I drove one. It really REVS and just sounds AMAZING, and it really does "make good power for the limited displacement", without resorting to turbos. I used to scoff at those "power per liter" comparisons, but eventually I ended up building for SCCA Time Trial classes. And guess what? They use displacement for most of their car classing - so the high powered 4.0L S65 jumped on on our list for swaps in this series.

S65 V8 ACQUIRED, CLEANED, AND ASSESSED

I did zero S65 research but in November of 2025 - when we still had plans to move our Max5 classed 1995 M3 to Max4 with this 4 liter swap, I found the cheapest S65 on eBay - and it was about 8 miles from our shop. That had to be a sign, right??

We picked that up and paid in cash, and were promised to also get a DME (engine computer) and some other things, but those never materialized. I paid half the going rate for an S65 and zero shipping, so I didn't push my luck too hard. The prices on the M3's DCT were actually fairly low, but we didn't get one of these just yet - I wanted to see the V8 under the hood (originally of the E36) before we spent that money.

This one had 120K miles on it, according to the seller. That many miles and years means it has some leaks - mostly from the power steering pump. We power washed the exterior of this engine right after unloading it off my truck. We gave up on hydraulic power steering systems years ago and our E46 has an EPAS steering column, so we pulled that off pretty quickly.

The power washer knocked off the worst of the black goo that had leaked from the power steering pump and valve covers. In a weird coincidence we happened to be renting a 1500 watt "Laser" cleaning machine on that day, so Myles burned off the grease and grime on the outside of the block. These machines are SO FREAGIN COOL and we used this non-stop for nearly two days - and might rent (or buy) one again.

We quickly removed the power steering pump, a/c compressor, and fancy cast aluminum engine mount stands - we wouldn't be using any of this. I was dying to get a real weigh on this engine!

We weighed it in several iterations but this 436 pound weight above left was with the alternator and plenum on, but also the dual mass flywheel. Due to some funky deep E-torx sockets we needed to remove that, it took a few days before the flywheel came off and it was a staggering 27 pounds. So the engine as we need it is really 409 pounds - and that is significantly lighter than the iron block S50 we had in the red 1995 M3. Heck, its almost as light as an aluminum LS engine!

I hate dual mass / heavy flywheels, naturally, so we are installing an ~9 pound dampened steel aftermarket DCT flywheel from Clutch Masters. This thing costs a LOT more than I've ever spent on an flywheel before, so it better shoot magic stars out the exhaust or something. Sheesh! Supposed to help the DCT to shift even faster, which is already an amazing thing. And a claimed 18 pounds less weight is always a good thing.

OIL PAN RELIABILITY MODS

After I paid for the engine I started looking into what the S65 needs to survive on track. Yes, this is the wrong order of operations, but I did know enough from seeing lots of these in FAST Time Attack cars to know they worked well with the factory wet sump engines. But the level of grip we had in mind (1.4-1.5g lateral) can strain even the best oiling systems, so it was time to cut up the oil pan to "make it better".

We got the engine mounted to an engine stand and then pulled the oil pan to check out the bottom end. It looked pretty good in there so we starting firing off some orders, and even got some free parts from a fellow S65 loving friend. I also ordered some used factory 2008-13 BMW M3 headers - mostly just to see how the flanges were laid out and to get a few measurements.

Then it was time to clean everything - the valve covers were filthy things, and I have since found that these magnesium units are problematic. We cleaned these in our parts washer and little desktop sonic cleaner, and they would need a couple of dozens hours or blasting, rework, powder coating and more - and they'd likely still leak.

Over time some coatings flake off and they tend to leak, no matter what you do to them. We will replace them with some identical aluminum versions - just so they won't leak oil like the stock ones do. I will show the shiny red valve covers in a future post.

I knew that the E9X chassis engines had no factory oil dipstick, which is crazy - so I reached out to Bimmerworld for their S65 oil dip stick kit. They were so jazzed about the S65 swap they gave us this kit, and a bunch of swag. We have seen more and more folks psyched about this swap, and with some good luck we might make this into a repeatable kit.

The oil pan had been cleaned to the max, and now Christian got it all messy again with rotary cutter shavings! We followed the Bimmerworld instructions, marked the hole location, then cut the hole for the weld-on threaded bung.

With that hole cut it was quick work for Myles to TIG weld that in place. The rigid dip stick tube screws into a 90 deg fitting into this bung, and the flexible dip stick shaft finds its way into the sump - so we can verify the oil level. Sure, there is a factory level sensor, but I'd still like a visual. "Trust but verify".

Next up was the installation of the AdvancedAutoFab (AAF) oil pan baffle kit. This is a very complex aluminum factory oil pan casting - and to fit this in place we have to CUT THE BOTTOM OFF of the pan. Yes, it is a scary as that sounds - and there are shops like Bimmerworld who sell new oil pans with this mod already done. If this looks scary, just buy that. We almost did!

The AAF instructions are great, however, and the main lower panel is traced onto the bottom of the oil pan, then you cut it out with a jig saw. The hole has to be pretty exact, so it took a minute to sneak up on the final shape. Then the two vertical panels that have the actual trap door sections (which hold the oil at the pickup screen under heavy lateral loads) are tacked in place and it is time to install the new lower panel.

Myles got this TIG welded and the new lower panel is flush with the bottom of the oil pan. That has to be seam welded and checked, so after it cooled it was filled with water to make sure we were 100% leak free. Lots of cleaning steps later it was bolted back to the engine block with careful torque sequences. Whew!

S65 + DCT INSTALLED AND MOUNTED!

After the November work on the engine, we had to complete some repairs to the E36 so Amy could finish her last competition of the year. Then we had some pressing work on another project (The Ocho) that took up this lift for a number of days. But on Dec 11th it was time to go buy the DCT. We had been chatting with Randy from EPIC Motorsports by then and he told us to get one from a yard that could also sell us the DME (engine computer) from the same car.

This means the DME is "married" to the TCM, the transmissions control unit. So no crazy work has to be done, as they are already coupled. The salvage yard had a low mileage 2012 DCT and I got that plus the DME (and key, key reader and body modules) from the same car. They also have a low mileage 2012 engine if ours turns out to be a dud, so we're keeping that shop on the short list.

After unloading this DCT 7 speed it was time to weigh it - my main pain point in this whole plan. The interwebs said this 7DCI600 weighs about 180 pounds, and sure enough - 178.6 lbs on our scale. That's a chunk, but it does include a fluid cooler and lines - which we are changing. The next morning the DCT was bolted to the S65 engine, but without the $1700 flywheel (I needed to save my pennies to get that).

The morning of December 12th the engine and transmission went into the E46's engine bay, with the radiator and support removed for easier access. I am not joking - this thing just WANTED to go in there, it fits perfectly.

The S65 oil pan has a big notch in the front section that the E46 steering rack and front crossmember perfectly fit into. We put a wood spacer between the swaybar and the front pump bump-out for the oil pump, but later realized that the E46 swaybar is going to rotate and run into this protrusion. We have a new swaybar design in the works to fix this, not a problem.

We want the engine as low as possible - as this is a significant chunk of weight, so lowering this lowers the CG of the whole car. The oil pan has enough gap to the crossmember but we cannot go any lower. Now its time to set the drivetrain angles and we begin with a transmission crossmember. Now luckily we already make 2 different versions for our LS swaps, so we utilized one of these and Myles designed a DCT adapter that bolts to the transmission and then to our existing crossmember.

continued below

**Fair!** · 02-13-2026, 12:42 PM

continued from above

This went through a couple of iterations but I'm happy with this 2nd version, which we have two poly isolators (above and below) between the DCT bit and the crossmember. We painted the DCT portion red after it was TIG welded to make it easier to see - this could go into production, yes that is the plan.

The engine mounts also went through two very distinct iterations, and the ones above right were the better of the two designs. These use some poly bushings to isolate vibrations and bolt to the block, with another bit that bolts to the crossmember.

These aren't painted yet, in case we need to make changes during long tube header fabrication - but the driveline angles are great and the engine cannot go any lower. Now, will the engine fit under the hood?? This was the million dollar question, and now that the engine wasn't being hung from the cross engine brace, we could test that

December 27th we finally had the "final" versions of the engine and transmission mounts in place, and I was able to close the hood without interference - yay! This is a Seibon carbon fiber "GTR" style hood with a mild bump near the plenum, which didn't hurt. This made me very happy.

ROUNDING UP PARTS

Because we're NOT using an aftermarket EFI system (for too many reasons to list) we needed a lot of factory E92 M3 components.

Lots of used E92 M3 parts were then located and purchased from eBay Motors - another engine wiring harness, a couple of DCT + O2 sensor harnesses (that I found out later was part of the engine harness, so now we have 3!), both 6 pin then 4 pin E92 M3 yaw sensors, and an entire E92 M3 DCT "body harness" with fuse box and relays.

I cannot count how many hours Jason and I spent chasing parts on eBay, FCP Euro and many other suppliers. Many of the duplicate orders were my fault, simply from not knowing this chassis or due to the many variations of the same components within this chassis. While trying to keep costs in check, I spent a little more than I should have.

Still, even with all of the extras, and the time spent weeding down the body harness, we're still ahead on what an aftermarket EFI system would have cost to buy, install, and tune. I will explain our cost savings later on, but we're doing OK for the wiring / sensor portion of this swap right now.

PADDLE SHIFTERS + NEW STEERING WHEEL QR

While we awaited parts coming in we had been discussing things with Randy Mueller of EPIC Motorsports we would need outside of the OEM parts to make the S65 and DCT transmission work well in a race car. Randy knows this engine and chassis well, so he was a wealth of knowledge. Since making the stock steering column work in the E46 was out of the question, he mentioned that the signals for the shifters are simply CAN controls.

After I did some research on aftermarket paddle shifters I ended up at Domi Works. I have since found Seems Legit Garaged has much of the same things, much of it also from Sweden, but without the crazy "weeks later you get billed" import tariffs.

The items above arrived in late December 2025 and I was blown away at thew quality. I made a short video showing these paddle shifter parts and how the magnetic switches work, and the feel of these is nothing short of magic.

I had also ordered a new NRG steering Wheel quick Release (QR) and a couple of 350mm dia MOMO steering wheels, which all arrived right before Christmas Day. I was bored, and we were closed on Dec 26th, so I came into the shop to figure out how to put all of this together. Domi Works had no instructions but it was pretty self evident. Tiny little button head screws hold the shifter switches to the backing plate and more fiddly bolts hold the paddle handles to the shifters.

I tried a few different ways for the shifter base plate and paddles to stay connected to the steering column, so that the QR is mounted with the wheel attached outside of that, but that would push the paddles waaaay to far back from the wheel. This arrangement above - with the paddles and wheel all outside of the QR hub works. That means the steering wheel + shifters stay attached together, and they would come off with the QR, but the paddle spacing was just perfect.

We were out of the countersunk M5 x 14mm long bolts needed to attach these 70mm bolt circle / 6 bolt steering wheels to the QR hub, but I found some online that arrived 2 days later (during the winter holidays, no less). I hate the "black oxide" bolts people often use to attach steering wheels (they rust) so we could use either zinc plated steel or stainless steel bolts - and I found stainless that could get her a week sooner. MORE ON THIS BELOW

When I was looking at the Domi Works paddle shifter mount, they had a version with 4 button holes, and I opted for that. After some digging I found these Otto P9 momentary switches and ordered two of them. One will be for the radio and the other for a "flash to pass". We ordered a 12 conductor "curly cord" from MilSpecWiring.com, which is actually just MoTeC USA - go figure.

The horn button should work with the NRG QR kit I installed, if we can make the clock spring on the Prius steering column work. More on that later, but having a functioning horn has saved me from getting backed into in paddock more than once.

LETS TALK BRIEFLY ABOUT HARDWARE MATERIALS

I ordered stainless M5 x 14 hardware to mount the steering wheel on Dec 26th, right in between the Christmas and New Years holidays here in the US. We were closed for 4 work days and 2 weekends in that period, as were all of my normal suppliers. I posted that I was pleased with the Amazon sourced stainless steel bolts that arrived on Dec 28th, just two days later, in the middle of "hell week" for shipping anything. It gave me time on this "off" period to configured the steering wheel and QR and paddles multiple ways and settle on the arrangement we have.

I shared the speedy delivery of these Amazon source bolts online and it completely triggered one person, who made some bombastic claims and basically called me an idiot. This person went on and on telling everyone how dangerous this was, and that I will die in a fiery crash or something. I said he was missing the bigger picture here, replied that I had used similar hardware on 6 bolt steering wheels going back 20 years, and never had a failure.

I've used these same "import" stainless M5 bolts to hold these 6-bolt steering wheels dozens of times going back 20 years without issue (above left pic was our Alpha E36 that we built in 2006), and some steering wheels use only 5 bolts, others only THREE. The overkill of having 6 bolts on a steering wheel can not be over-emphasized. And this stainless steel hardware passed my "engineering eyeball" test. I've purchased and looked at 300K+ bolts over the years, and I can spot pot metal / junk bolts pretty easily. Installing them and getting a "feel" for the metal is easy, and if you "Cam out" one of these Allen heads too quickly you know its bad stuff. This wasn't. And virtually all hardware is "imported" these days, and has been for 20+ years.

Anyway, this AI slop poster kept doubling down on social media, and I called him a nerd and made fun of the AI crutch he leaned on heavily used to produce truly awful, useless content that pretended to be "engineering" and useful to racers (it is neither). He kept going, so I sent him a message and told him I'm deleting his comments on my page, and to stop using me as his foil to generate content that he thought made him look smart. I again made fun of his AI generated slop "articles" he keeps pooping out. Somewhere in there, I bruised his ego.

It got heated and he posted his carefully curated version of our private messages publicly - the true act of a troll. Then he tagged me in yet another AI slop "tech article" about the evils of stainless steel hardware, how smart he thought he was, etc. What can I say, internet nerds abound? The truth is, I'm not, in fact, ignorant about stainless steel and other materials used in hardware. Vorshlag buys tens of thousands of bolts every year that we use in suspension components, and we do use some stainless in some components, when they have a high "engineering factor", or safety factor.

After being an engineer for more than 30 years, and understanding metals better than most (due to a stint working as an engineer at a foundry, where I daily tested metals for hardness and composition) I am one of the first ones to call out what I see as risky hardware use. I see folks using aluminum lug nuts all the time, which is simply a terrible material choice for something that racers will cycle way too many times not to be risky. The lower mass of aluminum (1/3rd the density of steel) still only saves "ones of grams" in a spot that isn't placed at a big enough radius on the spinning wheel to matter one iota for lap times. The cycle life is much shorter and the risks of a wheel coming off are too great. Same goes for stainless steel bolts (same weight but slightly weaker in some stats) and even same sized titanium bolts (1/2 the density of steel, 2/3rds the strength) used in many load bearing, critical, high cycling locations.

We normally source our critical stainless hardware from a known good hardware supplier we have used for more than a decade, but that takes time. If it is something we've never ordered before, like the M5 x 14m countersunk bolts I needed, it would take these steps: e-mail the supplier asking for a price, part number, and ETA (if they don't stock it). Then wait for their reply. Then send a Purchase Order with the numbers needed, and make minimum order quantities. Then they have to source the parts and receive them, then they deliver to us, and I pay the invoice. All of that takes 1-2 weeks normally, but during the Dec 26-28 period where Amazon supplied what I needed, my normal supplier were closed. So add another week OR TWO for the holidays. All for bolts that have likely 2x as many as are needed for the loads we see into steering wheels. The very slight impact on ultimate tensile strength that stainless had over carbon steel bolts simply wasn't an issue in this location.

On a race car build we tend to use stainless steel bolts in positions that have very low loads and that are exposed to the weather (or are otherwise cosmetic in use). The above images is from my S550 Mustang - the stainless bolts are holding on an over-fender and a Lexan window, each with many more bolts than is required to actually secure those parts. They are more cosmetic than mission critical. Conversely, the hardware used where the wing uprights bolt to the chassis plate are grade 12.9 zinc plated steel bolts, and meaty, and again - more than are needed to give us a safety factor.

So everything has a purpose, and we chose materials for things based on engineering data for sure, but also experience and common sense. Don't go off on anything you see online that you aren't 100% certain of, have loads of experience with (esp. if the thing sees load), and don't use AI slop to back up your arguments. And now back to your regularly scheduled content...

REMOVING THE STEEL ROOF (CARBON ROOF SWAP!)

This might seem trivial, but any time you have an E36 or E46 BMW it almost guaranteed to come with these stupid heavy retractable sunroofs, and on the E46 that adds 72 pounds high in the car. They break, they leak, they just suck - which is why it is so rare to find a "slick top" or sunroof free car. Of the dozens of BMW E36/46 models I've bought, I have found TWO slick tops. A composite "sunroof delete" panel is one of the first modifications most racers do when converting a street car to a race car - it gains head room and lops off a big chunk of weight from the roof for about $200 and a couple of hours of work. Very high reward for the dollars and time spent.

Those two cars above were both BMW unicorns, and while I still own the white E46 330Ci at left, I never should have sold the 1997 E36 M3 at right. Big mistake, and first on my list of errors to rectify when I get that time machine built!

One fix if you don't want to use a delete panel is changing the roof. This is a LOT more work, and what we decided to do here on our E46, as I speculated it would save use about 20 pounds - and that weight was up high. It helps that we had a carbon roof panel that came with the widebody car. And for our builds I normally do not track costs - but there is a real cost there, too. I'll show all of my homework on this roof swap!

Luckily, changing out the E46 roof panel is much easier than changing the roof on an E36, where it is welded to the A/B/C pillars. I did a steel roof swap using all OEM parts (roof panel and headliner) on my blue 2001 330Ci in my garage in 2009 and detailed it in this gallery. In that case we had to swap to an OEM steel roof panel (16.8 pounds) and also the associated OEM headliner to be legally allowed to remove the 72 pound sunroof. Dumb rules for an SCCA SOLO class I would never build around again. But they didn't allow $200 sunroof delete panels, so I spent $1500 and two days cutting off and welding on the new steel roof to save the 72 pounds of the sunroof. Rules...

On our build here, we don't have such trivially stupid rules to work around, and we could have kept the $200 sunroof delete panel and steel roof. But our class allows alternate panel materials for body panels, so we also could go to a carbon roof. As this build continues it gets more and more serious. How much steel were we leaving in the roof, way up high? I looked in another project gallery where we did an AJ Hartman carbon roof swap and the steel panel came out and was weighed at 24.1 pounds, and the sunroof cassette was 72 pounds.

And we had this beautiful carbon roof panel from another car (the red 328is that had all of the Flossmann widebody kit), which was never bonded on... this carbon roof swap would even "cost nothing!" (*but the labor and panel bond aren't free, dummy!)

If we could knock another 20 pounds our of the roof, that would be worth it on this race car, to me.

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**Fair!** · 02-13-2026, 12:45 PM

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Yes, even if we have to run ballast for SCCA Max4 class, that 20 pounds of extra ballast needed after the swap would be all at floor level, and more rear biased. So in mid December 2025, Brad got out the spot weld cutter and start cutting away at the 100s of spot welds that hold this panel in place around the perimeter.

As you can see in my instruction gallery from 2009, you do have to remove the two roof edge panels (they just snap in) and then remove the front windshield and rear glass. Removing the glass exposes the spot welds, but only after you scrape away the goo that cover them. Just removing the roof is 7-8 hours of work, then you have to bond the new one on (more work).

This one fought Brad more than other E46 roofs have, and it had to come off in chunks - as we had a cage right underneath that was making access tighter than normal. Yes, in hindsight, we should have removed the roof BEFORE welding in this elaborate roll cage (5 years ago). Again, I need that time machine to fix mistakes. If I ever get that machine, its gonna stay busy fixing my less-than-genius decisions of the past!

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After all of the chopped off roof bits were removed and stacked onto a bucket (and we tared the scale), almost exactly 10 years later on the same digital scale, the roof panel was once again exactly the same 24.1 pounds. We weighed the AJ Hartman roof panel at 6.9 pounds in 2016 also, and this panel we have LOOKS like one of his (just much worse for wear). I just weighed the fiberglass sunroof delete panel we removed, so lets do some math....

( 24.1 lb steel roof + 2.6 lb fiberglass sunroof delete panel ) - 6.9 pound carbon roof panel = 19.8 pound savings

That was my estimate from early on (20 pounds) and it is just barely worth all of this effort to save that much weight up high, for us, this time. At the cost of roughly 10 hours to swap the roof (at $150/hour) and the $1999 roof panel from AJ + $200 in panel bond & tools = about $3700 in costs. Every racer has a budget and every task has a cost / benefit analysis. This one would come in at $185 per pound, and to some folks that's a calculation they can live with. Add paint costs extra, if you don't wanna keep it raw (you should not keep it raw).

Brad got the raw metal left behind (between steel layers) cleaned up and primed with self etching zinc based primer. We'll use 3M panel bond to attach the carbon roof later, but for now we've just got it bolted on (the 4 factory bolts), but we would never drive the car like this. Also, don't look too close, because this roof panel has a ton of adhesive residue, from a clear film that covered the open windows on another car. It even needs some carbon repair in one corner, too. Hey, it was FREE and came with a car - we'll make it work.

FITTING THE FLOSSMANN FRONT FENDER AND NOSE

Flossmann Motorsport of Germany is a well known composites shop that deals with a lot of BMW models, and the kit we got on another E46 chassis a while back had the kit shown below, plus the carbon roof, plus carbon doors. We already had a Seibon carbon GTR hood and carbon trunk. So, in the end, we've got a lot of composites to work with that we paid pennies on the dollar for.

This is even the correct red we want to paint out car, but ours might look a big crazier because we're using 18x12" wheels at all 4 corners - which doesn't exactly fit with the Flossmann kit we have. More on that later. Let's get these pieces off our donor 328is chassis and fitted to our black E46.

The Flossmann front fenders bolted right on but the front nose was a bit weird, with a massive built in undertray. It had some decent ramps but this thing needed some surgery, because it was simply too heavy and we would be adding our own splitter (at a lower height) and this one would be superfluous.

There was quite a bit of structure inside the fiberglass nose, and it even had two factory bumper struts (which alone weighed 8.1 lbs) that we needed to remove. We've got a tubular bumper beam on this car already, which we will hang the bumper cover, splitter struts, and tow hooks from. Brad got to cutting...

Brad cut out 18 pounds of undertray and "bumper mount" structure and mocked that in place. It fits pretty well now but we've got a lot of work to do under the nose so this bumper cover went into storage for a bit while we got back to work.

CARBON DOORS + DTM STYLE MIRRORS

Amazingly I don't have a picture of the weight of a stock E46 door, but it should be around 80 pounds with the window, motor, crash bar, and inner door panel. One of the first mods we tackled in 2019 when this was an endurance race car build was to gut the factory E46 doors, and we got them down to 29.0 pounds. The thought was to keep it affordable in case we traded paint with another W2W car, we could just get more stock E46 doors and gut them down to this weight.

The red 328is once again delivers with two perfect carbon doors that weigh in at 11.8 pounds each, with the latches. that is 34.4 pounds lighter (for both) than what we had before, and ~140 pounds lighter than stock. These do not have the crash protection or roll up windows, of course, but this car has a massive roll cage and door windows are not required. We might add fixed Lexan side windows, awaiting approval of another Rules Request push. #WindowsUp

I hate the "barn door" mirrors that come on the E46 non-M cars, and the M3 versions are heavy and expensive. Both are too big and draggy for a race car. So we looked online, then extended to a global search, and Jason found these DTM style mirrors from a Polish rally site.

I came into the shop on Dec 24th and wanted to mount the doors and install these lighter weight / smaller cross section mirrors. These kits are not super nice, as they are not super expensive - the mirrors are a universal fit part and they are sold with adapters that mount them to the door. Several problems exist.

First, the mounting of the mirrors to the adapter plates is with self tapping screws into cast plastic holes. Not the most confidence inspiring, but again - these were under 50 Euros.

Second problem was the huge gap between the mirror and the adapter panel. This is just poor quality, and one of the RARE instances that a 3D printed part (and new adapter panel that FITS) would be better. I had the door fitted but it wouldn't close because it was hitting the cage door bars that weld to the lower sill.

On my birthday 3 weeks later, January 13th of 2026, I asked Brad to clearance the doors to fit the cage. I was tired of looking at this car doorless, and this was a necessary step the car needed to look more "complete". He taped up the bottom of the doors where they fouled on the tubes, took measurements, and made some careful cuts.

He asked me if I wanted these decals removed, which had been added to these doors in 2007!? Yes, I very much did. As you can image, decals installed for over 19 years put up a good fight, but Brad knows some tricks. With heat, adhesive remover, then some cleaner wax and a buffing pad he had these old carbon doors looking GREAT!

By the end of that day he had all of the clibbins cleaned up from the door notching, the doors closed perfectly around the cage, and they looked good as new. The E46 is now four colors, which was triggering my 'tism a bit, but we're gong to work on that soon. The goal is a solid red car, inside and out, but that just takes money! I was happy to see the carbon doors mounted, in any case, and that made my birthday better.

CARBON DASH OR OEM SHELL?

When we decided to go to SCCA Level 3 Safety, that must include a full roll cage built to a certain W2W spec (SCCA, NASA, etc). For our Max4 build this Level 3 upgrade allows us to gut the interior completely, EXCEPT for the full width dash panel. It can be an OEM dash (even gutted) or aftermarket shell of alternative materials.

I will say this right now - I'm weird about gutted interiors, and I hate it when there is no attempt at even a shell of a dash. It looks super janky to me.

Above is an E46 race car we built for a customer and the minimalist interior it has is what I like to see in all race cars we build - the OEM dash shell, with center console surround going at least down and around the shifter, and even steering column plastics. This one has an AiM MXG digital dash, blank off panels in all of the normal dash openings, and custom switches and dials within easy access of the driver.

To me, that looks proper, complete, it looks finished - not just some slapped together Saturday Night Special. It also has custom false floor panel boxes and a partial door panel - but that car had door glass (long story) and our GTR here will not.

I spent half a day chasing down all of the suppliers of "E46" style aftermarket composite dashboard replacements. The two above were some of the nicer ones at $1500-2000. Shipping something this big (and fragile) would be a nightmare so figure another $200 or more to ship. There can also be a multi-month wait for these, but we didn't have that kid of time to burn.

Some options (like the HGK and OCT) had multiple weaves and styles to pick from, and these looked great - but shipping something bespoke built like this from Europe? Yikes, that could take months and cost a fortune in shipping.

At the lowest price tier were the Big Duck Club fiberglass and this Fiberlab (on Etsy!?) options, but that's getting to some super sketchy sources. Quality, delays, plus known shipping turned me off on all of these options.

Back when this was a budget endurance build we had left the main mounting structure for the OEM dash, and had actually fitted a stock E46 dash shell into this car. But when it came time to trimming it around the cage the crew got a little chop happy and hacked the ends clean off. I was pretty unhappy that the dash got cut up this badly, as that doesn't reflect the build quality we would ever do on a customer car - and now that this is a Time Attack build, it needs to look like what we would supply to a customer.

I didn't throw away this cut-up tan dash - and recently bought some HARD Motorsport radio / HVAC delete panels and side vent panels. These are molded plastic covers that close up the holes. But still, this tan dash is cut up too much for my tastes. But it might have a use...

What I'd like to see is a more complete dash shell, like the one we built in this tube framed car above. That one had a composite dash that we cut into 3 pieces. The two side pieces that get trapped around the A-pillar tubes are permanently mounted, and we made the main center dash portion removable -with the windshield in place.

I helped Brad mock this tan chopped dash in the car in early February 2026 and we will use this dash as a cutting template for another gray E46 dash shell we have on hand. So as sloppy as this looks now, it will look as good as the OEM dash in the first picture in this section when we're done. And it will all be black, maybe even with the horizontal trim pieces in place. Watch this space.

THROTTLE BODY CLEAN UP + TOP END REPAIRS

The engine was cleaned on the exterior by a cleaning Laser and it just looked amazing. All of the weird pockets and webbed sections of the block were hit with the Laser and it cleans like nothing else. We rented that, and I sure miss it. The top end was kinda nasty, and the 8 individual throttle bodies (two banks of four) obscured the top end of the engine. We needed to remove and clean the throttle bodies to be able to clean the rest, and to access some things like the two gear driven throttle actuators (which got new gears).

In early January Christian attacked this task and got the two throttle body groups removed, and inspected the intake runners. the runners were cleaned (not too nasty) but the throttle bodies had some oily gunk in them.

Rags were installed into each intake port and the top of the engine was cleaned up with a vacuum, WD40, and a lot of hand cleaning. The throttle bodies got similar clean up, too.

This took some brake cleaner and rags, and a "three knuckler" cleaning approach. With the throttle bodies and top end of the engine cleaned up it was starting to look like a Vorshlag engine bay! Still a long way to go, and we will paint the sheet metal soon, but its looking better.

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**Fair!** · 02-13-2026, 12:47 PM

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One of the more obscure failure mods of the S65 is both the valve covers flaking off coatings as well as the plastic VANOS covers getting brittle and breaking, to be chewed up by the fine meshed timing gears.

MPorium BMW Service has a lot of experience with the S65 BMW V8 and makes some better-than-OEM replacements for these reliability strained factory parts. Neither is a improving power, or reducing weight, so I am showing those bits here openly - this is simply a cure for old factory plastics and magnesium bits that have not aged well. We will show the valve cover install next time.

During this work Christian replaced the VANOS covers using their S65 timing tool kit to keep tension on the timing chains and keep all of the cams timed correctly. The new OEM bolts to hold these on go deep into each camshaft and require a multi-step torque-to-yield sequence along with a timing chain tensioning sequence that is not a trivial task.

I missed getting photographs but the whole thermostat housing was removed from our S65 - I found these images online that show the t-stat housing, pump, and aluminum coolant lines. Our setup looked MUCH cleaner than this and we simply replaced the thermostat with a lower temp opening unit.

Of course we swapped in a new water pump while that was accessible - one with metal impeller (plastic impellers have a tendency to come apart and send plastic through a cooling system). I also ordered a new radiator hose, which we will use simply for their plastic quick-connect ends to allow us to make custom hoses for our custom, rolled radiator. I'll show that work next time.

AUTO BRAKE PEDAL + E92 THROTTLE PEDAL MOUNT

Some of these images below are from our earlier LS swap build with this E46 chassis, when it had a Tremec 5-speed and LS3 throttle pedal. That all had to change for the S65 and DCT, and since we had an automatic equipped E46 around to donate the bigger brake pedal, Brad went ahead and swapped that in here.

The pedal swap was relatively easy, with the dash out of the way. The 4 bolts that hold the brake booster are what secures this to the firewall. Why change the pedal box? Well we didn't need the clutch pedal anymore, and the wider "auto" E46 brake pedal will allow me to Left Foot Brake easier. We will add a dead pedal and foot box at a later time.

With the E46 auto brake pedal swapped in, it was time to look at the throttle pedal. The E46 pedal wouldn't give the correct signal to the E92 M3 DME, and the DCT version was even unique versus the 6 speed manual pedal. So I sourced a new E92 M3 DCT throttle pedal from RockAuto.

This mounts to the E92 M3 chassis with a "tang" and clip into the back of the pedal, and one bolt at the bottom. That makes it easy to remove, but we needed to replicate the "tang" that is part of the E92 chassis. I asked Brad to tackle this with an eye towards something we could reproduce, and he got to work with a cardboard template and hand made this aluminum bracket.

The E92 pedal clips into the tang at the top and bolts to the one rivnut at the bottom. Now we needed to bolt this to the E46 chassis and support the top at the firewall. He added to threaded "pointy bits" we use for marking things to a flange on the E46 chassis floor. Drilled two holes, added rivnuts, and threaded in the pointy bits. That was then used to mark the aluminum bracket...

He also added one spacer and bolt at the firewall to support the top edge. Once the bracket was bolted in... this was simply art. The E92 pedal slips over the tan and has the one bolt at the bottom, so we're ready to make the "BRAPP!" noises with this thing (*soon).

FIREWALL REWORK

Back in 2021 when this project was being built for an endurance car with LS power, we had the coolant reservoir and an oil pressure accumulator attached on the right (passenger) side of the firewall. We now need that space to mount the E92 M3's DME (engine computer), so this work had to be un-done.

I hate doing things twice, but this is one of those tasks that just couldn't be saved. There was one big opening (for a BMW harness pass-thru) we wanted to keep, but the two oval openings needed to be closed up, as well as a hole that somehow ended up after a tack-welded factory bracket was removed long ago.

Brad made the aluminum covers, which were mocked up and drilled on the engine side but mounted (with sealant) on the inside, and both were held in place with 4 rivets. Brad also cleaned up some unfinished work from removing some sheet metal bits that attach the strut tower to the firewall. These aren't really structural, and are more for housing things like a fuse box or master cylinder away from the engine. Those tack welded edges were ground smooth.

After the hole in the firewall was welded up and ground smooth, all of the raw metal was coated in primer. We will paint the engine bay the next time the S65 is out to make all of this pretty.

The driver's side had an elongated oval opening that was pretty big, and that needed a cover. Brad used the 4 holes for whatever went there before (fuse box) and added a bolt-in aluminum panel. There was a round hole behind the brake booster he also covered up with another aluminum sheet cover. We knew what was going through that opening soon - the E92 M3 body harness - and Brad then made a round hole to fit that. He then made the panel air tight with a perimeter gasket of 1/8" thick x 1" wide weatherstrip.

While this isn't "fire proof" material it is a damn site better than what we see in 90% of race cars - many of which you can see daylight through firewalls. Last but not least is the HARD Motorsport firewall cover. This is a formed aluminum cover that bolts in easily - priced too well to try to replicate. Time is money and we will often buy things "we could make" because it just makes sense.

A BETTER COLD AIR ROUTING + THE MYSTERY HOSE!

When this car was an LS powered endurance car one of the more strategic plans we had was an "over the top" air filter using a common Corvette stye filter. This is made for the 4.25" dia tube which is appropriate for this S65 engine also. We went to pretty extreme lengths to make room for this with the narrowed / custom radiator we set at an extreme roll, then built a little air deflector panel (which we will remake soon).

To replicate this air filter placement with the S65 v8 - to be fed exclusively from the two grills in the hood - took some research, a bit of paperwork and a little bit of a gamble. But we fell that it was worth it to keep the intake tube short and the filter placed in a really advantageous spot for cool, fresh, maybe even pressurized intake air.

The typical E92 M3 intake tube is pointed to the left front corner with a factory air box. When these cars came out in ~2008 I was at Dallas Performance one night when we strapped one to a chassis dyno. The power output was pretty good but it sounded "choked up". we removed the air intake tube from the airbox and it picked up 25 whp, if memory serves me. So anything we can do to avoid the factory airbox will only help. The oval opening on the S65 plenum was LARGE and oddly shaped, so Jason and I chased down aftermarket options.

The OEM intake tube has a bunch of corrugations and that always hurts airflow, so that was out. We looked and looked for a smooth bore silicone replacement, and found two from TEGIWA website in the UK. They made one with an EGR port and one without - and we wanted the latter. I went to buy this but they stopped selling to the USA over our ever changing "tariffs of the week". It has become too complicated to deal with the USA by our European vendors.

I tried to find this from other vendors but they were out of stock, so I sent a plea to Tegiwa in the UK begging them to sell it to me. They replied back to my email and said they could outside of their normal e-commerce system, where I paid the tariff up front and it eventually arrived.

It has the molded oval for the plenum in the weirdly large size, then necks down to round, then opens up again to mate to the factory airbox connection. But my idea was - let's flip this sucker 180 degrees and see if it points forward? When it arrived January 14, 2026, I ran out to the shop to mock this up!

It did in fact line up with a forward CAI inlet, just offset slightly to the driver's side. It looks a little funky, but there is a portion of the silicone tube that flares out to the stock airbox size that we will cut off, then using some round aluminum tubing / mandrel bend and the existing silicone hose and filter we have, it should scoot over to the right to better line up the filter. Otherwise that will trigger my OCD with an offset filter. It isn't perfect, but it is pretty dang good and I'm happy with the Tegiwa solution so far.

EPIC MOTORSPORTS TUNED DME

Very early in the S65 process, in fact last year when it was for the E36 chassis, we found Randy Muller at EPIC Motorsports. A friend told us to reach out to him, and his website showed all manner of S65 and DCT tuning packages. Without his help this swap would never have happened, and he has been instrumental in teaching us the ways of the S65.

He told us of a "stand alone" tune he can put onto a E92 M3's "DME" that will allow us to forego a lot of the body modules and CAN interfaces that the E92 M3 uses, all while race tuning the S65 V8 and DCT transmission. Sign me up!

I saved my pennies and sent him our DME in early January and he got the base tune installed and sent it back, along with a OBD2 CAN to USB interface, which we will use to give him access to remote tune this on a dyno after we get it running. This is the crucial bit to make all of this work in a swap.

The cost for this tuning is FAR less than an aftermarket EFI system would be, and even with the extra OEM harnesses I have purchased, we are still ahead. Plus, again, OEM level tuning for the V8 and DCT. We've been working on the wiring for a few weeks now and its almost complete, but we have been learning an "all new chassis" this whole time. Randy's team normally makes a stand-alone harness for swaps into race cars, but we are sticking with the OEM bits in the hopes it will save us time.

Placement of the engine computer (DME) was sort of dictated by the E92 chassis harness - which places it outside of the cabin and ahead of the firewall. No worries, we can manage that. The other slot on the DME is for the engine harness, which we already have. We're wrapping up the wiring now in February 2026, but I have more to show below.

MK60E5 ABS + HAPPY CACTUS CONVERTOR

One of the things Randy suggested we do is use the MK60e5 ABS unit from a 2008-13 BMW E92 M3, as it is better than the earlier MK60 units we have swapped in the past. He also suggested keeping the E46 M#3style speed sensors, as they mate up with the tone rings in the wheel bearings on this chassis. But since the E92 M3 uses a different signal type, we'd need a signal convertor.

After looking at his first suggestion of the 2008+ Z4M ABS (above left, which was spendy) the cost on the E92 M3 version was much more affordable, and it would plug into the E92 body harness we had secured by then (see more on that below). I hit the eBay salvage sources for one of these and the associated yaw sensor. Which I bought twice, because I was ignorant of the two E92 M3 versions. Brad made a bracket to mount the 4-pin yaw sensor in the correct orientation (very important!), shown below right.

But the signal types from the E46 sensors to the E92 ABS/DME were different. We thought briefly about trying to force the E92 wheel speed sensors to work, but the tone rings buried in the hubs were incompatible. So after I did some research and got nowhere, a local racer and friend who does a lot of ABS harness work (Alex Tambert) suggested Happy Cactus.

Tambert even told me which variation we needed - the "Switchable HAL/VR" version. This box is wired inline with the wheel speed sensors before it goes into the ABS computer, which then sends the signals on to the DME to make the DCT transmission work. This kit comes with a 12-pin DT style connector that we had to wire into our E92 M3 chassis harness. That includes the 4 pairs of wheel speed sensors, a brake switch, ground, and CAN.

Wiring this into the E92 M3's wheel speed sensor harness took a few hours, but Brad got it knocked out and it is ready to go. Happy Cactus gives a great wiring diagram and they have a Discord channel that they monitor and reply to throughout the day. Good stuff!

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**Fair!** · 02-13-2026, 12:53 PM

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MOUNTING A REMOTE COOLANT RESERVOIR

Instead of re-purposing a plastic OEM coolant reservoir, we tend to use these aluminum fabricated versions from Canton (80-202, 2 quart). These have a bung at the top (for a steam vent line) and one at the bottom (to tie into the heater hose circuit). We can also cut / weld in another bung if need to.

Placement is normally at the back of the engine bay to get the highest spot above the cooling system, but the S65 sits SO LOW in this chassis we could place it up front in an empty spot. Brad made a couple of brackets for this to bolt to, and we will plumb that into the system soon. I sourced a 22 psi cap for this, too.

WEEDING THE E92 BODY HARNESS

This was a choice we made early on - ordering a used OEM body harness from an E92 M3 to connect with the S65 engine harness and have both tie into the factory DME. We could have "hand built" a harness or even had an aftermarket EFI system + harness, but the latter would have cost more. We're also worried about aftermarket controls on the DCT, and even the S65 to some degree. Keeping this as much "factory" as possible, with EPIC's tune, should minimize any potential tuning issues AND costs.

I looked on eBay and found this 2012 BMW M3 "Body and dash harness" from a car with an "automatic" transmission. That was amazingly the same salvage yard across town from us and THE SAME CAR that we sourced the DCT transmission and DME + body modules from last December. Just dumb luck, but it worked out perfectly so far. $269 shipped. They still have the S65 engine from this low mileage car also, in case we have an issue.

I of course weighed the body harness from the E92 at 51.2 pounds (above left), which compares to the 49.4 pound body harness from a 2001 BMW E46 M3 (above right) we stripped a long time back. We decided then to keep as much of this as we needed but also to get as much dead weight out as possible.

Brad and Christian laid out this body harness in mid January and I took a picture from upstairs. It spread out over 30 feet and had HUGE bundles of wires. I thought CAN wiring was supposed to reduce the number of wires and weight in these harnesses?

After Brad stripped off the outer sheathing he laid it out as it would be in an E92 M3 - literally underneath our E46. That helped identify many things we didn't need, like window motors, radio and speakers, and even some of the lighting systems (we're doing that differently). Christian and Brad then connected all of the things we needed to control like the DME, CAS controller, Yaw sensor, ABS unit, key reader, and more.

We had a freak ice storm in there but when we were back and working Brad attacked this for a good 4-5 days. About half that time was spent looking at schematics from various sources, and weeding out huge chunks of this harness.

Eventually he had the 51.2 pound harness whittled down to 14.3 pounds, all wrapped in modern braid and marked for each branch that ended in terminations. That also included the entire fuse & relay box and large gauge power cables, some of which have been trimmed down during the installation, so it weighs a bit less than this. I was happy with that 37 pound drop in weight, and it connects to everything we need and more.

MOCKING UP REAR FLARES (FITMENT LAB)

We measured the Flossmann rear flares (which were bonded to the red 328is chassis we sold) and they just were not wide enough for the 18x12" wheel + 315/30R18 Yokohama A052 tire we want to build this car around.

Two months after ordering we still do not have these 18x12" wheels, but we have others in this size we measured, and the Flossmann bits were 3/4" too narrow. So we left those flares on the $500 chassis when we sold them. But I have a plan (that makes sense at least to ME) for the rear - which would involve TWO sets of flares.

Back on January 7th I ordered this new Fitment Lab "E46 Coupe Widebody" rear kit, which is relatively new. There weren't many pictures of this so it was bit of a gamble. After about a month these arrived from Prague via FedEx, and the parts were 100% undamaged in transit. I didn't waste any time and immediately mocked them up on our E46 coupe, which we clearanced for big tires with rear unibody work earlier in this build (like years ago - scroll back in this build thread).

We still have the skinny wheels on, but use your imagination. We had such good luck with the Fitment Lab Phase 3 kit on our E36, I was hoping for similar fit and finish, but this kit fit even better. It adds +60mm of width over stock non-M fenders, which technically is not enough but we knew this.

Now these don't look even remotely close to the actual GTR flares (above right), which the Flossmann kit mostly emulates. Those are the extended arch flares or "DTM" style flares. That DTM flare is not exactly low drag, but the Fitment Lab "coke bottle" style flare IS a good bit more slippery, and I like this style more. But again, we will need more rear tire room.

For the extra width we need AND to tie in the DTM flare look, a second set of flares will be added. Something like these Strom flares, or more likely the Clinched "universal" flares we show above right - which is what we had planned on using when this was an endurance build (as these are cheap / easy to replace with W2W contact). So yes, we are adding a flare to a flare - but it is because nobody makes a flare for an E46 big enough for the massive meats we want to run. Stay tuned to see if this double flare setup looks good or like a pig's ass.

NEW HEADLIGHT LENSES

This was simply a vanity thing, but for $38 I couldn't leave these old, yellowed, and foggy headlights in place. I learned this trick on another E46 - instead of throwing away good headlight housings, you just replace the lenses. Looks better for longer than just wet sanding / buffing old plastic lenses.

And easy swap and really brightens up the front end on this otherwise multi-colored mess. We desperately need paint under hood and on the entire exterior. That's after we fit wheels, adjust the flares, etc.

MOUNTING AND WIRING THE EPAS CONTROLLERS

We made a decision to get rid of hydraulic power steering in all of our race cars about 8 years ago and I do not regret that. We mounted this Prius electric assist (EPAS) steering column and grafted it to the E46 chassis years back - scroll back to see that We bought that column with the controller from a salvage yard, and now it was time to mount that box.

To make the OEM Prius EPAS work as a "stand alone" you need an aftermarket controller, like the ones from ServTronic. I ordered one in December from eBay but that was a MISTAKE. We didn't notice the $125 shipping cost nor the later $26.25 import tariff for this "$50" kit until it was too late. The tariff bill comes from FedEx weeks later, and if you don't pay it - they send it to collections.

Don't get me started - but learn from my mistake and get this directly from the Servtronic website. This company only builds EPAS control interface boxes, with both GPS speed based (new!) or rheostat variable force control units (what we have ordered many times). They even sell the high amp fuses / holders for this, but we'll use a 40 amp circuit breaker for this car.

In early February 2026 Brad got to work wiring in and mounting both the Toyota controller and the ServTronic box. We discussed locations and the length of the Toyota wiring put their box on the firewall right onto the HARD Motorsport firewall panel. As you can see below, the ServTronic box is mounted to one of the mounting brackets for that.

Brad just made some simple aluminum mounting brackets to hold the Toyota module, and bolted the ServTronic onto one of those also. This is all wired up and the high amperage power wire will run to a 40 amp breaker at the battery, which is behind the passenger seat area. We won't normally run a passenger seat, but we have one we can swap in for testing and the rare times we might take riders.

UTCC WRITERS SHOOTOUT - UPDATE!

This car is being built to compete in SCCA Max4 class Time Attack but we will also run it at the Ultimate Track Car Challenge during SCCA Time Attack Nationals in October 2026, here at ECR. This is one of my home tracks but we won't be powered high enough to contend for the podium for UTCC. Instead I got dragged into a little sub-challenge with other automotive writers, and the other 3 cars (see below) have more power and/or more prep.

We still have a long way to go before we're ready to talk too much smack - heck, our E46 doesn't move under its own power yet. Lots to do!

WHAT'S NEXT?

We are further along than what I stopped at above, but most of those tasks are unfinished so, I will stop here. I took a picture of the E46 at the time I finished writing this (below) and admittedly, the car looks like a big bag of garbage right now. White, black, silver, red, carbon - a lot of mismatched colors and almost none of them are right. Add in the skinny tires and lack of aero, and it looks like a work in progress.

Brad has the E92 fuse and relay box mounted behind the dash, the DCT shifter is mounted and wired in, as are a bunch of other modules. We have parts stacked up from Domi Works, more parts coming form Bimmerworld, and will make a big Fragola hose and fitting order for the fuel system next week. I will show these other components getting mounted next time.

We also have all of the parts to convert the front suspension from E46 "no-M" to E46 M3 - spindles, lower control arms, and new hubs + wheel speed sensors. We've got business reasons for doing this suspension swap and will make a video showing the measurements and differences between these E46 M and non-M parts soon. I also just ordered LED headlight bulbs, a wig-wag box, and Brad has a secondary harness just for lighting, wipers, and turn signals going in.

The expensive but lighter Clutch Masters sprung hub DCT flywheel just arrived, which was the last drivetrain piece we needed to bolt to the S65 before it goes in for the last time. While the engine is out we're painting he engine bay, too. Tune in next time to see more!

Thanks for reading!

Terry at Vorshlag

**Fair!** · 06-30-2026, 04:18 PM

Project Update - June 30, 2026: Well here we are 5 months after my last post, the SCCA Time Attack season is well underway, half the year is gone, and we are still a ways off from starting the S65 engine in this E46. I am frustrated that this car isn't already on track and being dialed in for the 2026 SCCA Time Attack National Championships happening IN MY OWN BACK YARD at ECR in October. I feel like the year is slipping away!

There has been some work done on the GTR, but we had about a 2 month lull in work on this project due to our other project cars gobbling up ALL of our shop time, plus we were short one employee for a year. I had to borrow Amy's J37 Honda V6 powered widebody FRS to try to get some Max4 regional season points, and that has been hit or miss (just lost a rod bearing, replaced engine, built a huge oil pan, etc). Our Fox Mustang also gobbled up more shop time than it should have, as I got the scheduling priorities backwards for that car and this E46.

But in the last 6 weeks we have staffed up, poured more work into the E46, and made some real progress. Work on the FRS and Fox are pretty caught up, so we will be pushing HARD to get this E46 worked on every single day until it runs. But looking at what I just wrote, which spans work from January to April 2026, we still did a good bit on the E46 along the way. Let's catch up!

UPGRADING TO E46 M3 FRONT UPRIGHTS - WHAT IT TAKES

It is no secret that this $100 coupe chassis was a "non-M" when we started this build back in 2019, but we have upgraded the rear to E46 M3 "everything" - subframe, brakes, differential and control arms. For a variety of reasons I wanted to upgrade the front to M3 bits also, mostly so I didn't feel like a phony calling this an E46 M3.

I've not seen this explained well so we began rounding up the other parts we KNEW were different, like the E46 M3 front Lower Control Arms, M3 front spindles, and eventually M3 front tie rods (inner + outers) when the toe was way off.

There are some differences in the spindles that we could see - some differences are hard to see until you break out measuring equipment. There is a bit more camber built into the M3 spindle and the steering arm is longer, as well as angled differently where the tie rod meets.

One of the more obvious things was the brake caliper mounting holes were spaced further from the centerline. One of the biggest changes was the distance from the strut clamp to the hub face, which impacts lots of things in geometry. I should have made a video.

BIG BRAKE OPTIONS + BRAKE COOLING

Part of the reason I wanted E46 M3 spindles was to be able to find more big brake kit options, as well as to create a new brake cooling deflector for this spindle. I know as much as the next guy the consumables costs, heavy mass, and lack of stopping power the OEM brakes bring to track cars. After we upgraded to E46 M3 uprights at both ends we could just "start with OEM M3 stuff" but I know that would be foolish, especially up front where 80% of all stopping happens.

Normally we have an aftermarket brake manufacturer we work with and can get at wholesale prices, but those are all gone now. PowerBrake stopped supporting "cars", StopTech went bankrupt, and Wilwood stuff is uninspiring. We priced AP's two E46 options for the E46 chassis - the 325mm rotor kit was $3250 and they quickly go past $5K per axle, and that was 6 months ago. Tariffs have made a lot of these options pretty spendy. That is a a lot of coin for things that we will still have to replace regularly - esp. pads and rotors. But I admit we need a Motorsports level billet caliper and 2-piece rotor up front.

I really wanted to use a 355mm 2-piece rotor, for the weight and potential of this car, but I could not spend $5K on the brakes. spent a LOT of time trying to piece together a BBK with AP calipers to be able to use a 355mm rotor, but the hassles and import tariffs made it impossible. We even ordered the 355 x 32mm 1-piece rotor above, which was very cost effective - but heavy. Compared to the 325mm 2-piecce AP rotor, it was +15 pounds more per corner.

In the end I decided to use some 4-piston AP calipers and the 325mm 2-piece AP rotors I picked up from a local BMW racer for a great price. These were part of an older AP 325mm E46 kit, but he didn't have the caliper brackets. We will 3D scan everything and design then CNC machine the brackets, then make the brake lines. Sure, it is not as big as the 355mm AP kit, but it should work plenty well for our approx 2700 pound finished race weight.

When it comes to brake cooling, we had a really nice non-M E46 brake cooling deflector (above left) that mounted right to the spindle. But the M3 version we made mounted to the control arm, which was less than ideal. So with the M3 spindle installed the the 325mm AP rotor bolted up, we got to work (above right).

We made a lot of measurements and the 3-dust shield holes in the spindle were very close, and with just a slotted hole on one of these we were to make a combined E46 deflector that worked on both spindles, shown above. These can be fed from the factory brake cooling tubes or from splitter ramps, which is how we will feed them. I'll post up when we make the caliper brakes and hoses, and out back we just have new M3 calipers and rotors on hand.

MORE WIRING FUN

Shortly after my last forum update, Brad had the E92 M3 body harness weeded down and ready to install with two custom openings in the firewall, to minimize rubber grommets.

These used the E92 M3 plastic grommets and fit the openings perfectly. We even had room to shove the Happy Cactus harness through the firewall opening.

After lots of time spent weeding the E92 harness the fuse box was mounted to a custom bracket under the passenger side of the dash. This gives a good spot for that fuse box, and lots of open circuits we can utilize.

A second bracket was added to the right side which makes the fuse box more rigidly mounted (see above right). We will have an access panel behind the glove box to get to the fuse box for trouble shooting, of course.

MOUNTING THE DCT SHIFTER

While we do have the DomiWorks paddle shifters behind the steering wheel, the factory E92 M3 DCT shifter is still a necessary item for finding neutral and park and some other "non-racing" aspects.

As you can see above we had a long shifter hole cut into the tunnel from a previous drivetrain swap (LS + Tremec TKX) so I asked Brad to make a proper aluminum panel to cover that, to which w could mount the factory E92 M3 DCT shifter.

I purchased this in two parts from eBay - the shifter base with the parking cable and the separate handle and boot, which connect to the shifter base with wiring. That lights up the indicators on the DCT handle. After doing some research and asking around we were advised to remove the parking lock cable, which we did.

We also ordered a DomiWorks parking cable delete kit (above left, at right) that goes on the transmission itself (see above right). On that order I also ordered the DomiWorks DCT "cooler to AN adapter kit" (above left at left), which we will soon plumb to its own oil cooler with -12 AN lines.

Brad installed the shifter hole cover with 6 bolts into rivnuts in the chassis, with button head bolts and 1/8" thick x 1" wide weather strip seal along the base to make it air tight.

The plastic loop was then cut off the shifter (that had the parking cable) and that allowed the shifter to fit perfectly inside the E46 dash's lower shifter section. Yes, we are using a skinned OEM E46 dash for now, and might even add the plastic center console to finish out the interior.

WIG WAG HEADLIGHTS + HORN

We had some old E46 M3 headlight housings left over from another project, but none of the bulbs, bulb holders, or wiring connectors. So I spent some time to track down some LED bulbs, wiring harness ends, plastic bulb holders, and even new gaskets for the headlight housing surrounds.

Why have headlights on a race car that will never be on track at night? It is all about getting drivers' attention on track, when they are not seeing the big red widebody M3 coming up behind them. There were so many wig wag controllers, many of which had different patterns you could alter with your phone using an app... ugh. I just wanted a simple left-right or inside-outside bulb alternating headlight flash.

Brad wired up the wig wag controller, relays, and push button for the steering wheel for the "flash to pass" function. The LED bulbs I picked were inexpensive but they LIGHT UP the world, even in full sunlight. Oh yes this is exactly what I wanted!

This video shows how the wig-wag headlights work in this car, and for passing slower cars or cars on cool down laps, this will definitely help.

The top left picture shows the finished wiring for the headlights, and above right is the loud horn we added. Yes, I put horns on all of our race cars, and a functional horn button on the steering wheel. Why add a horn? Two reasons. I've been almost backed into in paddock TWICE and a horn saved that contact. In some race cars with a HANS on your rear view is terrible, but the horn helps! Also, I've used a horn on track more than a few times when some out-of-class slow poke is blocking... beats using the "chrome horn"!

BIG WHEEL CHOICES - TWO SETS

So wheels and tires are a huge choice, but based on our experience with the 315/30R18 Yokohama A052 tire we picked an 18x12" wheel right away. Any wider of a tire might be overkill for the power and weight we're shooting for (400 whp / 2700 pounds) and I really love this tire - it heats up fast and should be good for 2 hot laps in this car, which is more than I need.

We have access to a number of wheel companies but picked an inexpensive Konig Hypergram 18x12" ET20 wheel with the BMW 5x120 bolt pattern for this car when it was on sale last year for "Black Friday" - a flow formed wheel that has a really low weight (20.4 lbs). And it was in stock! It was a stupid good deal, but we ended up waiting FIVE MONTHS for them to arrive. It is a long story but it took a number of calls and emails to get this wheel set shipped without paying the extra $600 they wanted after the first of the year when they had a price increase.

During that excruciating 5 month wait I lost all hope and punted - and ordered a 2nd set of wheels from Apex, which arrived within a week. These were made for a 6th gen Camaro, so they had the 5x120 bolt pattern but the wrong bore size. They also needed a 20+ mm spacer at both ends to fit our car. We mocked it up on the car with washers and they worked, but we needed to bore the hubs out to the BMW 72.5mm to use hubcentric spacers. They weighed a bit more but they would lose a little weight after we machined the hub bores.

The funny thing was both sets arrived within days of each other. We have machined wheels before and had this set ready to go in about an hour - most of that time was securing the wheel to the CNC bed and centering the hub bore to the tool.

Both sets of wheels were only available at the time in black - which is my least favorite wheel color. We mounted up a set of 315mm scrubs to the Konig set for now but before the car is at SCCA Nats (I hope!) one or both sets of wheels will be powder coated in some wild color.

continued below

**Fair!** · 06-30-2026, 04:28 PM

continued from above

REINFORCE STRUT TOWERS

I am a big fan of reinforcing the thin strut tower tops on the E36 and E46 chassis. This $100 E46 chassis had some pretty mushroomed towers, and if you scroll back in this thread you can see how I fixed them with a chunk of 2x6" lumber and light hammer work. They weren't cracked, which is nice. If you have ever cracked a tower just know - it is not a fun repair.

To prevent cracking, we always try to convince customers to install some of these OEM style reinforcement kits. These are stamped steel and shaped exactly to match the E46 towers, and we stock these for the E46. It is cheap insurance, and coupled with a strut tower brace on top it is the sandwich of strength! Some folks literally just slide them under the tower, but of course we like to weld them in.

To start this repair, the strut assembly must be removed, then you need to prep the area for welding. We use this air tool called the "Crud Buster" to remove undercoating and paint, and it did the job. The only raw steel is around the lip where the reinforcement will be welded to the tower.

This was stitch welded from underneath (overhead welding, not a fun job) then the seam around the lip got seam sealer, then the whole underside got zinc based primer to prevent any corrosion.

AEROCATCH HOOD LATCHES AND STRUCTURE

This was a tricky situation that we created after my dream of "over the top" cold and and forward air filter location. We purposefully ran a narrower but THICC radiator that was rolled heavily, to only need airflow from the lower grills. Chopping out the center of the radiator support makes the room, but we now have to add structure back to be able to latch the hood closed.

The two sides of the old radiator support were very floppy and we needed to stiffen that up just to hold the headlights. Normally we would use the two rubber "hood bumper" holes for the hood latch pins, but that section is completely gone. So Brad got to work based on a quick planning meeting we had.

He started with cardboard mock-ups and they looked good, so he then went to .080" thick 5052 aluminum sheet - bolting those wobbly sections of radiator support to the bumper beam and plating that all up on both sides.

With those panels now firming up the radiator sections, we then chatted about a bracket that bolted to these plates made of .090" aluminum - first in cardboard then in aluminum sheet, bent up to fit where we wanted the hood pins to land.

With those brackets supported it was then an easy task to mount for the pins, then use some "pointer" bolts we have for this purpose to mark the underside of the carbon hood - for that set of holes.

All of this goes back to some planning we did a week before choosing where to add the hood pins. With the sloped nose being too curvey for a fore-aft AeroCatch latch placement, we went sideways up there. The GTR hood venting holes also compromised where we could put these latches. The AeroCatch latches "usually" come with a 1:1 printed template, but this set didn't so he just used the top plastic flange as the guide (see top left) traced onto some painters tape.

With the hole for the pin located underneath from the pins, there are two hole saw sizes we use to make the oval, then the air body saw and a steady hand cut out the section in between - this was all done with the hood off the car, as to not get carbon dust anywhere near the engine. The hood was then bolted on and - viola! - we had two hood pins lined up and the whole hood is securely mounted.

MOUNTING THE FACTORY E92 M3 DME

In BMWs the term "DME" stands for Digital Motor Electronics, which is what the rest of the world calls the Engine Control Unit (ECU) or Engine Control Module (ECM). We are using a 2008-12 BMW E92 M3's factory DME, and it is normally mounted in a bunch of plastics that we simply cannot use. The length of the engine harness dictates that this computer be very near the engine, so we came up with a plan.

Brad made a mounting plate and three brackets to secure the DME to that. These are just sheet aluminum cut and bent to fit around the edges, as shown above. The brackets have 1/8" thick x 1" wide weatherstrip tape on the back side to cushion the DME a bit from vibrations.

The plate was trimmed to fit a very much NOT flat spot on the firewall on the passenger side by the engine, as seen above. There are spacers to keep this panel mounted somewhat flat and vertical. This panel mounts to the firewall via rivnuts and bolts, and the 3 edge brackets bolt to this panel with more rivnuts and bolts. The last shot shows it mounted to the painted firewall.... which brings us to the next section.

PAINTING THE ENGINE BAY

Painting cars is not something that we want to do at Vorshlag, but our builds have to look a certain way for business reasons. I really like brightly painted exteriors with matching gloss painted interiors and engine bays - makes our race cars all matchy matchy body color, and not everyone will bother with that. We already paid to have the interior and cage painted bright red, but it cost more than I had hoped and took longer than we have to spare right now. Nobody budgets the time #PaintJail takes.

We also try to avoid black or grey cars - or boring black or grey or engine bays. The painter we have used for 15+ years has had a big price increase lately, and they are super backed up. Long story short, we're painting the engine bay now in this project, before we get buried in other tasks. That was part of the push to get the strut towers reinforced, too.

Brad started this work on February 24th, first by removing the drivetrain from the engine bay. We were done with major mods to the chassis here, so other than smoothing some sheet metal bits we had cut away and grinding off some un-used OEM threaded studs, it was time to clean then scuff the engine bay sheet metal. Any bare metal was primed, like some areas around the towers where we removed some sheet metal sections.

About a week before I decided to push for the engine bay painting, we made several spray-outs using various red paints, to try to match this cage color. Then I found a picture from 2019 when the interior was painted, saw the paint code used then, and ordered four 11 oz cans of that GM Victory Red in "automotive paint", which is made to be a base + clear. I also ordered several cans of USC 2K High Gloss Clear, which is really hard and shiny clear that has to be "activated" prior to use (a button on the bottom of the can).

Once this automotive based, color matched paint arrived, Brad did one more spray-out and the color was pretty close - as long as you know that the base coat has zero gloss. I knew we were there on the color, so Brad started laying down disposable plastic and taping edges. The shop floor was covered in plastic also.

One mistake was not using a portable paint booth for this work - it was a large enough area being painted that we had some red overspray, but it was MUCH worse with the clear (which got all over the carbon panels on the Mustang that took 2+ days to cut and buff to remove).

After the day of prep, Brad laid down two coats of color, burning through 3 cans of red over the factory engine bay (non gloss) paint. It was very red but also dull - and that is as far as most OEMs go, just the base coat and not the clear. BORING!

After a day to dry the 2K clear coat was laid down next. Brad wisely used a disposable suit along with the full face mask and breathing filters he used for the color. That laid down pretty quickly and the two cans was enough for one coat - but we probably could have used a second coat with one more can.

Later that same day the two remnants of the radiator support we had missed were painted red then cleared also. Always forget something!

So over about 2.5 days and maybe ~10 hours of work the engine bay is eye popping red, with a super hard high gloss finish. 4 months later it STILL looks this good, and I'm happy we went to the extra effort. I'm so happy with the work here that now I want us to tackle the exterior. In the image above, the engine bay was already being plumbed with brake lines, wiring, and other bits we had removed for paint a weekend after the clear dried.

CRANK PULLEY TRIMMED

That same day we took the time to trim down the OEM crank pulley to remove the A/C belt section of the serpentine drive.

This is something we meant to do months earlier but we did it here, with the engine out of the car, to make it easier to get to. The admittedly not very heavy 1.1 pound aluminum pulley was chucked up in our lathe and the outer 4 rib section was cut away with a parting tool.

Of course I didn't get to weigh the final piece but it lost probably half the weight. More importantly we now had much more clearance to the bottom of the rolled radiator with the fan in place. It was bolted back to the stock balancer and it was time to get the engine and trans back in the car. Almost...

EGR BLOCK OFF PLATES

This E46 will be a dedicated race car, and as such we don't need to meet street car emissions - and SCCA Max lets us defeat all of those things. So of course the two EGR injection ports needed to be blocked.

I had ordered these FelPro gaskets a week earlier to be able to seal the back of the block with some steel plates that were hand cut. In hindsight we should have CNC cut these and sold them on our website, because we had a heck of a time finding them.

These were bolted in place with some high temp RTV to seal them up, and now the engine was ready to be bolted to the DCT and then go into the car again.

DCT FLYWHEEL FITTED

It was time to get the drivetrain back into the E46, but now was a great time to power wash the DCT box - which had a little schmutz on the outside of the case. We installed the DomiWorks fluid cooling adapter and got the case as clean as we could without a cleaning "laser".

continued below

**Fair!** · 06-30-2026, 04:36 PM

continued from above

Months earlier I had researched and been warned to buy the somewhat pricey ClutchMasters sprung-hub steel flywheel for the DCT. The lighter, cheaper, solid flywheels can lead to vibrations and damage to the transmission, so I trusted that advice.

Christian and Brad got that admittedly complicated setup bolted together and onto the DCT with the starter lined up and everything torqued. It looks simple but is actually multiple pieces, with the flywheel bolted to the crank (under the spring hub) and the spring hub section attached to the DCT dual clutch basket and the flywheel.

We took the time here to paint the engine mounts and DCT crossmember parts bright red, then the DCT was bolted up to the S65 V8 for the first time with an actual flywheel that engaged the clutches.

DRIVETRAIN BACK INTO ENGINE BAY

Still in the first week of march but after the first SCCA TT double-points 2-day event of the year, which we missed with both Max4 cars (the FRS and this M3). I was beginning to panic that we'd miss the whole season so we only worked for a bit longer on the E46 before about a 2.5 month break.

I was dying to see the S65 and DCT back in the painted engine bay, so brad worked on that - shoving the drivetrain in with the entire front off the car, and the subframe out. That makes this work much easier.

With the drivetrain back in and subframe bolted up, the painted radiator support / headlight surrounds went in, as did the tubular bumper beam and headlights.

One of the rare times where an Amazon part works out - this $24 pair of headlight trim gaskets replaced some crusty 2003 era bits on these used headlights. We already replaced the lenses and bulbs, so these were looking pretty sharp now. Neither of those headlight repair parts were sourced from BMW and that saved hundreds.

MASSIVE CARBON SWAN NECK WING WITH C-PILLAR REAR UPRIGHTS

A week earlier, while the engine bay was being painted, the AJ Hartman carbon "fulcrum" wing we ordered arrived, all 14" x 72" of it! This was ordered with a pair of swan neck mounts at a width we had planned for weeks earlier. We really should be concentrating on the FRS (in the middle of an engine swap) but I was too excited with shiny new carbon bits!

We have weighed this wing many times and this one was a tick heavier, but AJ seems to be using some additional glossy coating on the exterior. And after cleaning water spots on earlier wings, this is a welcome addition. First step after weighing is mocking up where we want the wing to be relative to the car, and then join the car with the wing...

We are building for a class (Max4) that allows 8.0 SF wings (this is 7.0 SF), mounted as much as 10" above the roof and up to 6" behind the rearmost portion of the rear of the car. We're going to shoot for about 4" above the roof and the full 6" rear mounting. Once again we are going for a "flying C-pillar" type of mount, with the main brackets in the back seat area.

Above left I am holding some earlier versions of a wing upright we made for another car (my S550 Mustang called Trigger), which were too high for that car. Well this car has a taller roof, and we can cut these down to fit our needs. Brad copied this upright in some press board so we could chop those up without ruining the expensive aluminum bits we were hoping to recycle.

Jason and I met with Christian and sketched out what we wanted for brackets that would bolt into the back seat area, which he first made in cardboard then Jason made in CAD with a couple of windows cut out to save weight. These are made from steel because there will be a lot of load here. The pair is bolted into the rear shock towers and our chopped up back seat structure in the E46.

Above left you can see the steel brackets now bolted to the modified aluminum uprights. The steel bits will protrude through the rear Lexan window and the aluminum uprights bolt to those, going down into the car. Super strong, and we were able to trim down the aluminum parts from that previous project and reuse them.

To finish off the wing install with a flourish I asked our new CNC engineer Arturo to take a sketch I had given him and design some endplates with a few geometric shapes above the element, who's holes would allow air to bleed off. He chose hexagons and it really worked. Jason saw the design and said "make it 50% bigger!", then Arturo finished the CAD design and Christian CNC plasma cut these from .080" thick aluminum. They are YUGE!

I made a short video showing the new wing setup before the endplates we made, with a walk around of the car on that date - April 22, 2026. Click the image above to view that.

S65 HEADER FLANGE MACHINING

Quick design task before the S65 went back into the E46 was to scan the exhaust ports (from a paper rubbing) and make a CAD drawing of them. Then we CNC plasma cut a quick test piece to verify our measurements.

We will use this later to CNC machine a stainless steel flange for the long tube headers we want to make.

VALVE COVERS + PCV DELETE

Many months earlier I stopped by and talked to the folks at Mporium BMW Service in McKinney, TX. These guys know the S65 and S85 better than anyone else I know, and they even make their own products to fix reliability issues on these. One such part that hooked me early were their cast aluminum S65 valve covers, which were identical to the factory magnesium units, but they just didn't fall apart. They have been helpful on a number of fronts!

They made us a set with bright red powder coating and it perfectly matches the engine bay color - which was a total fluke. It was finally time to install these, but first we wanted to use the OEM units we had cleaned up to check for clearance at the brake power booster.

Sure enough, once the drivetrain was locked down there was one small fin that had to be trimmed, which is just a channel for routing the OEM wires. The guys got that trimmed on the new red unit and it was installed with new gaskets provided by Mporium.

Now one of the things we commonly remove on all engines in dedicated race cars are PCV systems. These are made to suck crankcase vapors out and pump them into the intake manifold under decel (high vacuum), but that ends up pumping OIL into the ENGINE to be burned. Not good for the engine, as it causes detonation. So we looked at options for a valve cover vent system to an external vented catch can, found all offerings lacking in some way (too small of a port), so we designed our own.

After scanning the OEM bits Jason made a design and we tweaked it to use a -12 AN fitting for the breather, since bigger is better here. We CNC machined those out of some 1" thick aluminum we had and squeezed 3 of them into one plate, then machined the other side on a fixture.

We ordered new BMW O-rings for the two mating surface - one is plugging a port, the other sealing a flat opening - and installed massive M22 ORB to -12 AN fittings. I ordered some stainless hardware to bolt it to the valve cover and it was done. Two 24mm rubber caps seal off the openings in the upper plenum, of course.

We will likely anodize these parts black once in production, but this raw set works for now. We also installed a NRW oil filler cap - which ironically was supposed to be used for crankcase venting, but was just too small. It still looks super fancy, but in hindsight it was a fairly frivolous purchase. So many race car purchases often are, I guess.

CARBON ROOF REPAIR

This carbon roof panel came with the red 328is that had the Flossmann bits and carbon doors, which I stupidly had stored outside under a car cover for too long. During that time the roof got damaged. It is a long story, but this stuff should never have been outside - that's on me.

The underside looks perfect (of course) but the top side has some cracks. Christian has been repairing carbon fiber panels here for a bit and has made some carbon patches and epoxied those in place, which are under the battery below.

This won't ever be a "pretty exposed weave" piece when we're done, as it will be body worked and painted. I've learned the hard way that exposed carbon panels get damaged by the sun and rain, so we just paint everything carbon now - even wings!

MOUNTING ABS UNIT + HAPPY CACTUS

These two items needed to be mounted now that the engine bay was getting attention. Sometimes the orientation of the ABS unit is critical, but on the Mk60 ABS the yaw sensor is mounted elsewhere. This gives us a little freedom, but normally we want the ABS very near the brake master cylinder.

Brad came up with an elegant solution to mount the ABS and Happy Cactus convertor box in a small space normally occupied by the E46 fuse box. He staretd in cardboard of course.

Once into aluminum sheet he got to work making the holes, dimple dies, and bent flanged. This ended up as a 3-piece bracket with the Happy Cactus mount shown below.

The main ABS bracket bolts in to 3 points of the chassis, some of which already had threaded holes. The Happy Cactus bracket was fairly simple and bolts to that.

With the ABS mounted Brad then begin plumbing the two lines to the master and the 4 lines to each brake caliper on the car. He ended up re-using the line to the Right Front wheel, and just bent the E46 line to fit (see above left) but all of the other lines were replaced.

The two rear lines were spliced into the original E46 lines under the driver's seat. In the end it turned out nicely with new lines bent and flared to fit this new ABS layout.

NEW INJECTORS AND FUEL RAILS

The folks at Mporium spooked me about the S65 injectors - which have a small filter built into it that can never be serviced. So even though I had the OEM injectors serviced, sonic cleaned and flowed, they can still fail at any time. After a recent snafu with tuning on another car with low end injectors (pay for tuning and dyno rental twice because you're "saving money" and you won't use cheap injectors, trust me!)

I broke down and bought Injector Dynamics ID1050s for this car. Nobody is going to find fault in this brand and we have used these on a half dozen cars successfully - and EFI tuners love their data.

When it comes to fuel rails I also don't screw around with cheesy aftermarket extruded aluminum rails and flat steel mounting brackets - as I've seen these fail first hand, with bent brackets that allowed the rails to lift up, spray fuel everywhere, and often go "en fuego".

We are plumbing a full "Return Style" fuel system, with -8AN lines to and from the engine bay and a regulator nearby, so aftermarket rails make the most sense over OEMs. Normally with aftermarket rails you lose some OEM reliability by omitting the injector securing clips, but not with Nuke!

Normally I use another brand for our billet rails, but for the S65 we went with Nuke Performance out of Sweden, who makes a really nice billet CNC machined set. We had a few small pieces missing from our order and not only did the folks step up and ship us the parts overseas no questions asked, they sent me a really nice shirt with their logo. Hey I'm a sucker for free swag, but this is a NICE ass shirt - and some damn nice parts.

For the fuel pressure regulator we used this DeatschWerks adjustable regulator with gauge, which Brad mounted to the strut tower after planning out how the fuel lines would be run. I will show the fuel lines next time.

WHAT'S NEXT?

I had written two more sections and had more to go, so I'm going to stop it here. We have a lot more done than this, of course, but with modern attention spans I've probably already lost half our readers.

Next time I will cover a lot of ground like the fan mounting, bodywork fitting, a quick weight check in June, radiator ducting, cold air intake, and LOTS of plumbing. I mean a lot of plumbing. But for now, that's enough.

Thanks for reading!

**Fair!** · 09-03-2026, 04:15 PM

Project Update - September 3, 2026: We have been very busy since our last update here, and we are pushing to get the S65 to fire up very soon. We have the 2026 SCCA Time Attack National Champs in October and no testing in this car yet, so we look at the task list and calendar every day.

Most days now we have 2 or 3 guys working on tasks for this car exclusively, and in the past 2 months of doing that we have made huge progress. Our white board "to do" list keeps shrinking.

The toughest task in this round of updates were the custom long tube headers, and none of that went according to plan. But its done, and we moved on to more work that was held up waiting for that. Noticed that in a recent Grassroots Motorsport Magazine they are using our E36 Hellrotten car to promote UTCC, which is a one day event held during the 2026 SCCA Time Trial Nationals - I had signed up late last year when we were still putting the S65 + DCT in the E36! I need to update my entry for the E46, because by damn we're going to have it running by then! Let's cover the last few months of work.

RADIATOR FAN MOUNT

We put electric fans on all race cars we built - why? Well it is simple thermodynamics. A radiator needs airflow across the fins to remove heat from the cooling fluids, and if the car is sitting still or even moving below about 40 mph, there isn't enough airflow to cool the radiator. We can often be stuck sitting in grid with the engine running in 100F+ heat sometimes for up to 20 minutes, and that is when engines can easily overheat.

If the car is not a street car and never will see an air conditioner, we use these slim, low cost, Mishimoto electric fans shown above. "BuT wHy dOnT yOu UsE a SpaL?!" because the Spal has almost the same airflow for nearly double the cost, and again - these aren't daily driver street cars with insane horsepower. Just enough flow to keep it from overheating while idling in grid works.

The 16" diameter fan we mounted an older Mishimoto model (not the curved vane) but we had it on hand, so it was what we used. To mount these we like to use either architectural extruded aluminum angle (like you can find at big box builder stores) or we make some using a piece of aluminum sheet. We cut it on out on our big shear, then bend at a 90 deg angle on the brake, like above.

Either way we trim away any bits that can block airflow, with just enough on the fan mounting flange to attach to the fan housing. This 16" fan was just a hair wider than the core of this admittedly narrow radiator, but this is still a good fit. There are 4 bolts that hold the fan to the brackets and 4 bolts that attach the pair of brackets to the extended flanges on the top and bottom of the core.

The fan is spaced roughly 1/4" away from the core, for maximum airflow potential and it keeps the fan blades from touching the radiator fins. The bottom of the fan housing is close to the crank pulley, as seen above. This is why we cut the A/C belt section off the pulley, to gain that space.

EPIC MOTORSPORTS OIL DIVERTER VALVE KIT

The factory S65 oil filer housing has a thermostat controlled bypass to push engine oil through the factory E92 M3 cooler. Even at opening temperature this bypass limits oil flow greatly, so EPIC makes this diverter kit that removes the thermostatic function

Randy at EPIC sent us this kit and you can see the OEM piece if replaced above. Ben at Rogue sent us his AN line adapter kit for the S65 filer housing also, which we will use to plumb the Derale oil cooler - thanks to both companies for these two sponsorships. It all helps!

NOCO BATTERY MOUNT

I am not going to repeat what I've written about NOCO's line of Lithium Iron Sulfide batteries, which are very light and affordable - you can read that in our FRS, Fox, or E36 Hellrotten threads. We've settled on this $199 NLP30 700 cranking amp unit and they are awesome. Some folks love spending 2-3x as much for other brands, but these just work too well to look at those anymore.

We need to make a more production ready battery mount for this thing eventually, since we put it in everything, but for this one Brad made a custom bracket base and captured mount while I was away in Utah hiking at National Parks. Nothing exotic, just a flat aluminum sheet base with some angle holding the base in two axis with an over-the-top mount that holds it down in the 3rd axis.

Looks like he used some solid aluminum hex bar we had for the vertical stand-offs, which bolt to the base and have bolts threaded into the top for the hold-down. He made the hold down out of some aluminum sheet bent into a half box, with lightening holes along the top.

Before I had left town we had discussed WHERE to place the battery. Now I don't have to run a 2nd seat, and honestly I almost never get requests for riders. In 3 seasons I took ONE rider in my S550 (Trigger), and this being a Level 3 Safety (fully caged and gutted) we decided on no passenger seat. So the NOCO is sitting behind where the passenger would go.

And as you can see above right, there is still room for our seat bracket base on that side, if I ever change my mind and want to put a 2nd seat in there. Brad also wired up the main battery lead to this low, centrally located battery and also added the CARTEK battery isolator and two major circuit breakers behind it. Nice and tidy, that bit of work.

EXTRA BRAKE PEDAL SWITCH

Now the wiring on this car is a mash-up of E92 M3 body harness + a stand-alone Painless Wiring chassis harness. As such we needed two different brake switches. The OEM E46 brake switch sensor is wired into the the Happy Cactus signal convertor for the ABS and the other drives the brake lights on the Painless harness.

Brad made a small bracket and mounted the second "old school" switch near the brake pedal arm, which triggers when the brake pedal moves ever so slightly.

It was all wired in and tested, with a relay on the brake light circuit, and it all tested perfectly.

REMOTE FUEL SURGE TANK

As I have written about many times, we like to keep the modern plastic "saddle" tanks when they are so equipped, because they are in the perfect place for ballast (ie: fuel) - right under the back seat, down low, and they "crash well" compared to old steel tanks under the trunk. Less pendulum effect on the polar moment, too.

To make that work on a road course when the car can make 1.7g lateral in long corners, to prevent fuel starving, we add a remote surge tank. Yes even with two fuel pumps - one in each "saddle" - high g cornering can easily starve one of those, and that means the engine goes lean, loses power, and upsets the handling dramatically. We will show the twin fuel pump install into a stock E46 tank later, but we "Y" those together and feed them into a BIG surge tank, this monster form Radium Engineering.

Inside the Radium itself we are using a single Deatschwerks DW300 pump that will pull fuel from within this container - which is always kept fuel - to feed the engine. We also chose the optional "float sensor" (see above left) for the top of the Radium, which lets us know when the level is starting to drop inside the surge tank. That feeds a red light on the dash for a "COME IN NOW!" signal. It took a couple of weeks but a massive Fragola order arrived in early June and Brad got back to work.

After discussing locations of things underneath the flat trunk floor (a piece of steel sheet here, which we later replaced with aluminum) the Radium surge tank was bolted up front of the trunk area near the spare tire well forward section. Then Brad laid out all 4 lines that will pierce this floor panel with -8 AN bulkhead connectors. We chose -8 AN for all fuel lines due to the modest 414 hp of this engine - its enough to feed more than 500 hp. We also laid out the Deatschwerks fuel filter as well.

Brad plumbed all of the lines in the trunk at this point with Fragola 2000 series braided lines in -8 AN and through the fuel filter up top. He also started to run the lines underneath to the fuel tank, but only started one line as the tank needed to be laid out and installed. More on that in a bit.

NEW BRAKE LINES

The car we started with was a roach - it was pretty picked over for parts, and several of the stock brake lines were even missing. We decided to re-plumb the system with 3/16" copper-nickel alloy lines and re-used the ends from the ABS unit we bought and wherever else we had something useful. We don't like using stainless brake lines, as that material is much harder to flare, and even with "the right tools" they can often split and leak.

The lines going back to the rear were still there but the sections under the hood were not useable, so they were cut short at the back of the engine bay (above right) and spliced with unions. Then Brad ran new lines up from there for the 2 rear channels on this 4 channel ABS system to the ABS unit.

Under the hood he plumbed from the E46 M3 master cylinder I bought used with the M3 booster and reservoir attached to the Mk60e5 ABS unit from the E92 M3, which I also found on eBay. These 2 channels were plumbed then all 4 lines to the two fronts and the two lines under the floor. We managed to re-use the E46 chassis' right front line, but the rest all were missing or too mangled to use. The above right image links to a short video showing how he makes these lines - a quick tech tip vid!

E46 SEAT BRACKET BASE

In early June of 2026 we took a flat CNC cut plate that a former engineer here had made in 2019 and left in the car and turned that into a fully ribbed and welded Vorshlag seat bracket base. This is how we do most seat installs the past ten years - which makes for a very short, rigid base to mount seat side brackets or sliders to.

With these mounted and tested, I took them for a semi-gloss black powder coating in June and that's how they sat for another 6 weeks, until we had the time to mount the seats - and didn't need the access that the seat blocks.

We will evaluate some small changes to this design soon and release this as a production part to go with our collection of seat brackets, including the E30 and E36 designs.

WIDEBODY PANELS FITTED

When I bought these Fitment Lab E46 rear over-fenders I wasn't sure they would clear an 18x12", and neither was the manufacturer. Just like on our E36 with their system, we managed to fit something wider than any of their customers had at that point.

This was a quick first mockup but I was very pleased, and we had once again took a gamble on some flares (the Flossmann front and Fitment Lab rear) that actually clear our ideal 18x12" / 315/30R18 tire setup. This kind of luck never happens, so I didn't buy any Lotto tickets that week (*I've never bought a lotto ticket, since I am not bad at math).

LONG TUBE HEADER FABRICATION

Again it is early June and we haven't started to make the long tube headers yet. We searched for a supplier of the flanges, to no avail. So I ordered up a slab of 1/2" thick stainless steel and we CNC machined them on one of our mills. This was not fun.

That proved to be the easiest part of this header fabrication - and for various reasons it was the longest fabricated header we have ever done, and my least favorite result of the many we have completed. Me and the new fab guy did not communicate well and many changes had to be made along the way.

We had pushed to make the stainless flanges then he just cut some thin steel ones to use for the IC Engine Works plastic bits. I had wanted 1-7/8" primaries but he made them from 1-3/4" to fit the available space.

I wanted more ground clearance than we ended up with on the driver's side. It was the fabricator's first set of custom headers, but the end result is a set of functional headers that we can never reproduce, and took 8 weeks to complete.

I like to start with the flanges and collectors, which was done (eventually) above left. Then join the two ends. There were compromises made to make them easy to remove that will likely hurt power, and definitely exclude these from EVER being a production part. No chance. ZERO.

I hope they make decent power, because this is the most expensive set of headers we have ever made, if you add up the hours, which I will not do. Passenger header was easier, as mid-way through the driver's side work he stopped and made that one. It tucks up nicely to the tunnel and away from the DCT transmission.

The driver's side has a several compromises and it hangs low, but they are long tubes with ALL the length. And compared to the OEM bucket of snakes they should flow better.

While the OEM S65 headers are "eQuAl LeNgTh" they use 1.4" diameter tubing and had tortured bends to make that happen. Our set has 1.75" diameter tubing and much longer primary lengths - to the point that "equal length" no longer matters, if it ever really did. These go into 3" collectors and V-bands with O2 bungs before that. We were just glad for this nightmare fab project to be over, and in the future we will just 3D metal print exhaust manifolds for something this tight.

continued below

**Fair!** · 09-03-2026, 04:18 PM

continued from above

MOUNTING TWIN DERALE OIL COOLERS

Now with an 8400 rpm engine spinning up in the revs and a 7 speed DCT churning up fluid, we decided on twin fluid coolers using Derale stacked plate 10000 series heat exchangers, part number 51678. We have used this size on many cars and since we have the same "16 row" versions for both, we can mount them side by side using Derale's 50022 mounting kit, shown below.

My original goal was to mount them in the wide lower grill opening of the Flossmann front nose, but my crew talked me into separating them into the two fog light openings instead. When Christian showed me how well the core fit into that opening, it was obvious this was the answer. This way we were not stacking these coolers in front of the radiator, and that makes each one more efficient.

Derale makes mounting kits for single width setups, but we had the double wide and just cut the dang thing down the middle. It works, and Christian mounted each assembly to the tubular bumper beam with two isolator mounts on top and one underneath.

The engine oil cooler is plumbed in -10 AN (I would have preferred -12 but space constraints pushed us to -10) and the DCT cooler is going to be plumbed in -8 AN. I'll show the tubular strut used for the lower mounting point on each side.

QUICK WEIGHT CHECK + CLASS CHANGE?

This day June 10th, 2026 - and since this E46 wasn't ready yet, I had been racing in Max4 in my wife's widebody Honda 3.7L V6 powered FRS since May. We missed some early events in March and sadly had a weird engine failure and missed the early June event, so the regional championship season for both of us was toast. But I was still racing against my wife in the same car / same class - and that wasn't smart. Have you ever been married to a racer and shared a car???

We got the FRS sorted, and with a new custom 10 quart oil pan has been rock solid reliable. AND FAST. We decided after the May TT event to "divide and conquer" and, while still driving the same car, I would voluntarily "up-class" to Max2 and she would run Max4 in the same car. And guess what? We won both classes and I set the Max2 class track record at that July event at ECR.

Originally we were building both cars to the Max4 class in SCCA Time Trial, and as you can see above left, the minimum weights were different for her 3.7L NA powered car (2700 with driver, but the car and driver combo is about 240 pounds over that) vs my 4.0L powered E46 (3000 pounds with driver). But I can voluntarily run an otherwise Max4 legal car in Max2 and weigh up to 300 pounds lighter than the Max4 minimum, as shown in the blue box above left.

Normally Max2 is made up of higher powered cars with up to 6.2L built engines or even up to 6.4L those with forced induction (see above right), but at higher minimum weights - and most that show up are above even that. Admittedly the hot ticket is likely a built 2.9L forced induction car at 2800 lbs, but we could be "in the hunt" in the M3 here if we can keep it around 2700 pounds with driver. We had originally planned to meet this weight anyway and run 300 pounds of ballast for Max4.

This June 10th weight check at 2398 lbs was encouraging, as it had all of the body panels and seat in there. With my weight a bit under 200, and this chassis weight check, we had a new goal. We have since begun a weight loss scheme on both car and driver, and the move to Max2 was confirmed with my TT Nationals entry for this car, which does not run, and might not until right before the October Nationals event here at ECR.

TOW HOOKS + SPLITTER STRUT MOUNTS + MESH GRILL COVERS

The vibration isolators for the two Derale coolers are visible below, and the inboard lower mounts for both are a piece of aluminum tube squashed flat at the ends and bolted to the bracket and isolator. You can also see the stainless steel mesh we added two all 3 openings on the Flossmann nose.

With the mesh installed it was time to add my "lazy man" tie down / tow hooks up front to the bumper beam. This is how I like to strap down cars into a trailer, as well as how we winch them inside after an event. Not everyone agrees with this method, and that's OK. Just know that we have made it work on almost every car we have tried it on.

With some careful measuring of the bumper beam with the nose installed, a spot is marked in blue tape and magic marker for the slots that we will cut for thw tow hooks. We make these from 1/4" thick steel plate with a 2" ID hole, mandated by NASA and SCCA for tow eyes.

With the tow hook fitted to the slot, it is then tack welded in place and the bumper cover is removed. Then the tow hook is welded fully to the bumper beam, which is right behind the fiberglass nose. I'll show the splitter strut stand-offs better in the next section, but they are there for use with the splitter, obviously.

FORWARD RADIATOR DUCTING

It is mid-June at this point and we have 3 guys working on the E46 most days. Here Christian and I discussed radiator ducting with Jason and we came up with a plan to build a duct that tied the Flossmann lower grill to the heavily rolled radiator. As you can see the radiator sits very low, and will get 100% of its airflow needs from the lower grill - we have something else planned for the upper grills in the hood.

Using big chunks of Ramboard cardboard that we buy from Home Depot, he cut out the forward radiator duct and taped it together. This arts and crafts step is crucial and every minute you spend in this stage saves you ten minutes once you get into metal. Do not rush this step as it is much easier to cut something with hand scissors and patch up a mistake with blue tape than it is once you are in aluminum sheet.

Turning this from cardboard to aluminum ducting is a straight forward affair, and with our large sheet metal shear and the sheet metal break we can cut and bend this stuff cleanly and quickly. There is still precision that is needed, and a lot of detail work, but we have done this enough times to make it look easy.

This forward ductwork is completely mounted on the radiator side, and just wraps around the fiberglass opening on the front nose, but air cannot get around this ductwork. Air coming in has to go through the radiator. There is a panel at the top that bolts on and seals it up, and with the nose on you can see that almost 100% of the lower grill opening is being put to work.

ABS WHEEL SPEED SENSOR WIRING

While much of the header and front ducting work was going on, Brad went through the tedious task of adding all new twisted pair wiring to each corner for the E46 wheel speed sensors. These are then connect to the wheel speed sensors at each corner with 2-piece Deutsch connectors and secured inside the OEM plastic boxes, just like stock.

The wiring all ends up near the ABS unit and wires into the Happy Cactus signal conversion box, allowing us to use the E46s' wheel speed sensors with the normally incompatible E92 M3's Mk60e5 ABS unit.

OVER-THE-TOP COLD AIR ROUTING

Whenever we are feeding an engine air we want to grab it from a pressurized source AWAY from any heat, especially areas past the radiator. I see so many builds with a "hot air intake" with a filter just sitting there behind the rad - such a nasty shortcut that can lead to Intake Air Temp numbers of 140-160F or more! Our COLD air intakes always lead to IATs within 5 degrees of ambient, and if we managed to get a box with high pressure air coming in, the "ram air" potential is... well really hard to quantify, as dyno testing never shows this. But we will still do it!

When we rolled this radiator in 2019 we had set it up to feed the (then LS V8 powered) with this Corvette C6 style carbon fiber K&N air filter with it placed just behind the upper grill openings in the hood. When we switched this project from LS to S65 power in 2025 I immediately began hunting for a way to tie the plenum for the 8 ITBs that feed the S65 from a routing that was straighter and fed directly from this same filter in this same location. It took a lot of work but we pulled it off.

The S65 upper plenum normally has a very drastic 90 deg turn to a nasty OEM airbox that is behind the left front headlight, and I've personally watched a 2008 M3 dyno'd with that airbox removed and watched it pick up 25 whp. So the stock airbox was never an option. The TEGIWA silicone intake hose with the EGR delete that we bought from the UK was flipped 180 deg to take that turn straight forward. The K&N filter had a central inlet that was in the wrong spot, and too small, so Brad cut the back of the carbon fiber filter off...

He then built this aluminum cover that is bolted to the remaining part of the carbon filter housing, then a 4" diameter aluminum tube that necks down to an oval that is wider than what feeds the C6 Corvettes' 6.2L LS3 engine. That was then tacked on

This pair of pictures above was on June 30th and it was getting mocked up and ready for the air filter housing to be welded up to the new inlet tube and for the oval panel to be 3M panel bonded to the carbon.

A while later brad came back and made this rear panel to seal off the airbox from the engine bay. Another panel will eventually be mounted to the top side, mounted to the bottom of the hood, to fully encapsulate this box behind the upper grills, for that magic "ram air" performance.

After that work we came back and painted the aluminum portion of the filter he built and panel bonded that in place. This whole layout exceeded my expectations and makes all of the hard work of ordering the custom radiator and rolling that to an extreme angle worth it.

COOLANT LINES

The coolant piping on the S65 engine is new to us, but whenever we see "BMW" and "plastic coolant lines" it is a trigger, and we do whatever we can to remove the plastic quick connect hoses everywhere. Because they always, always fail.

At the front of the engine is this coolant distribution pipe made of actual steel, but it has one hose barb end, one O-ring boss end (for the engine block), and one quick connect end. You can't fault BMW for ever being consistent! I wanted to replace the two external ends with AN style weld bungs, which Matt knocked out quickly. Sadly only one of those - the forward protruding one, would end up being used with an AN line. This is what feeds the bottom of our metal remote coolant tank, which has the pressure cap for the system.

That front line assembly was bolted back onto the block and then the rear crossover steel pipe was removed. It could have, probably should have been converted to an AN weld bung, but it was a barb on that end and we just sourced a long silicone hose with a tight 90 deg bend on it there and ran it up front.

Above left you can see a -4 AN hose made to go from the steam port on the water pump to the top of the coolant reservoir. Above right is the AN to barb to silicone hose heading to the distribution pipe at the back of the engine. I'm not 100% happy with that layout and while it will likely outlast the car, it will probably get replaced with a AN end at the back pipe and a proper AN hose front to back at a later date.

When it comes to radiator hoses, we almost never go to the giant AN fittings and hoses that some do, with -20 lines or bigger. We like to use these aluminum mandrel bent pipes, add a raised barb (see above right), and use heavy duty silicone hoses with straights and bends in them to connect water pump to radiator.

We have had exceptionally good luck running these on 20+ cars with weird swaps, where OEM hoses no longer fit and where the expense and weight of going to giant AN hoses doesn't add up.

FUEL TANK - PUMPS AND PLUMBING

What we're going for here is to keep the OEM saddle tank, which we like to run for the reasons posted above in the surge tank section. But we wanted two pumps and I also wanted to get rid of all plastic fuel lines and OEM quick connect fittings. Those are a failure point we cannot afford. The image below links to a video that shows a lot of what we did:

Now a pair of these billet E46 fuel pump hats would have worked with less effort, but those seem to be built to order and would take 3-4 weeks to arrive, and we needed to button up the fuel tank sooner than that. So I bought this Radium "fuel pump hat" kit that is made for the E46, but only made to have 1 or 2 pumps on the "big saddle" side only.

If you are reading this, just plan accordingly and spend the money on two of those billet hats shown above left. What we did to save time ended up being a real pain in the ass, but it will work.

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**Fair!** · 09-03-2026, 04:19 PM

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We used a bulkhead connector and drilled through the upper billet section of the hat that normally allows for the pump addition. This lets us have a return on the "big saddle" for the overflow from the surge tank.

I had already purchased two new OEM style pump hats for an E46 and the quick-connect to AN adapters (above left), but a racer I know just had one of those fail and it torched his whole race car. That is what pushed me to go this billet fuel hat route. Anyway, the "fuel level sender only" side is only supposed to have a level sensor and a return line. We instead plumbed the 2nd pump's output from that port, and we ran submersible wire through the tank to the other hat, which had the extra provisions for the pump in that bulkhead.

So now the two top hats are billet, each side has a lift pump (DW340 lph units), and the extra return line does go through a real bulkhead. It is all AN lines and fittings with no plastic or quick connects to fail. This is all plumbed to the trunk mounted surge tank and all of the wires go through the factory fuel pump covers, as shown above. You can see the final under-trunk plumbing in the big picture shown in the Lower Control Arm section below.

OIL AND DCT COOLING LINES

Plumbing the DCT cooler and engine oil coolers was done with 2000 series Fragola hoses and fittings throughout. The Derale coolers are setup with -10 ORB ports but we often over-size the lines for engine oil coolers to -12 AN, which causes less of a pressure drop. Every fitting, every inch of hose, and the cooler itself all causes pressure loss so over-sizing can often be done to mitigate that.

One compromise we made was that the Rogue Engineering fittings for the S65's oil filter housing converts them from the BMW port to a -10 AN male, so we decided to just stick with -10 AN hoses from filter housing to cooler and back this time. We will monitor oil pressure very closely and if that seems to be an issue we will go back and address this.

The oil cooler is mounted on the left side of the bumper beam but the filter housing is on the right. This was driven by some constraints on the DCT cooler, but the hose runs aren't that long. We use these dual hose spacers periodically for any runs of hoses we need to contain, otherwise a P-clamp (see below right).

The two DCT cooler lines start at an adapter on the transmission I ordered from Domiworks in Sweden. They were setup for a -8AN so we stuck with those sizes. Generally the transmission does have a "full flow" cooler circuit, so this 1/2" size isn't a pressure killer. The driver's side long tube header was going to be right in the way so Brad planned to cross over the back of the engine oil pan to run up the passenger side header, which has a lot more room for these hoses.

The two -8 AN Fragola hoses go up and back to the cooler on the right front corner. The lines have been secured away from the headers on both sides and a big heat shield for these plus some wiring was made from a piece of sheet metal and some insulated DEI heat shield material near the right side header.

CRANKCASE CATCH CAN + PLUMBING

I wrote about our "PCV delete" kit we designed and machined in the last update, and now it is time to plumb from those on each valve cover to a Peterson Oil systems vented catch can. This is our go-to crankcase catch can we use on race cars and it has not let us down. We put one of these on every race car we build, and have for a dozen years. Why spend more for this vs the cheap import units? Size matters - and the volume of this unit dwarfs the little Amazon cans.

I like seeing the catch can mounted at the highest point of the engine bay and fed with giant hoses from baffle openings from each valve cover. This time Brad built a bracket that mounts to a flat panel cover he had back by the BMW "DME" (engine computer). I wanted a remote drain hose, and we cobbled together this with some pre-made -4 AN line to the 1/8" NPT connection at the bottom of the can, with a 1/4 turn valve to allow that to drain out to a hose behind the right front tire. We check this volume and drain the cans between track events.

Here you can see the triangular bracket Brad built has 3 dimple dies added and the band clamp from Peterson is mounted to that. The above right pic shows the catch can mounted to the wiring cover back by the DME, and Brad had started on the -12 Fragola hoses.

One hose goes to each valve cover and they both run "down hill" to allow oil vapors to drain back into the head in some cases. Anything captured gets stored in the can and drained out the bottom between track days.

REAR UPPER CONTROL ARMS AND SPHERICAL FRONT LCA BUSHINGS

The last two suspension arms that had issues on this car included the rear upper control arms and the front lower control arms. The rear upper arm was touching the axle boots on both sides, and we could not figure out why. One side had an aftermarket axle and the boot was a bit too large, but the other side was OEM and it was dangerously close. We were not using the springs mounted above the OEM arm so I wanted to go aftermarket to gain room and possibly lose weight.

The front lower control arm was an OEM piece - which I prefer to use over the $1500+ drifty boi arms that some folks go to. We don't need an "angle kit" and their magic geometry improvements for "grip" cars just didn't pan out when we used them in the past. But the OEM arms have a big honking bushing at the rear we needed to replace with a spherical. Let's start out back first.

We looked and looked for a replacement arm for the aluminum cast rear upper arms and so many solutions from the past had dried up for the E46 chassis. I even made a plea to SPL Parts to make this arm, and explain in this video why it is needed. We found these steel fabricated arms above from DriftShop in France, so I was super skeptical just from the name and the "Made in Europe" claim. The price sure looked too low to be made there, but I took a chance and ordered their adjustable (for camber) arms and some spherical adapters for the front LCAs. The parts didn't look half bad.

Amazingly the room gained to the rear axle's outer CV boot was dramatic (see above left), and that was what we needed the most. As I mentioned in this video we didn't really lose any weight (just 0.1 lbs) over the larger aluminum upper control arm, but they feel pretty beefy, the rear upper swaybar mount is there, and as you can see above right, it can be adjusted for camber while still mounted on the car without removing the arm - something cheaper arms often miss. And the inner bushing is a massive spherical, so that is a win.

We'll keep a close eye on these and see how they work long term, but for what we spent I couldn't be happier.

Up front we had these big honkin Whiteline "dual durometer" LCA bushing housings. They are both too squish for the cornering loads we will see and they ended up pretty close to the long tube headers, so while I was on the French driftshop site I bought some spherical LCA bushings. First step was Matt pulling the Whiteline bushings off - never drove 10 feet with these installed.

As you can see the round spherical (which is quite large) doesn't fit the cast aluminum hex end on the E46 M3 lower control arms. We looked at several ways to fixture up this control arm to make the end round, as the instructions of "sand to fit" seemed like a real hassle and makes for a less than round finished part. After my wacky ideas, Matt just took an extra stock arm we had and used a 15/16th" Diablo branded hole saw and slipped it over the hex - damned if it didn't work!

Matt then took some 400 grit sand paper and smoothed out the rough edges and the spherical fit on pretty dang well. All of my crazy ideas of hold the arm in the lathe and cutting around it, fixturing up in the tire machine and turning that into a lathe - silly but they would have worked!

The finished setup bolts in place of the factory lollipop and allows for some caster adjustment, but more importantly - it gains us a lot of room to the headers and gets rid of a sloppy bushing. Next!

PANEL BOND CARBON ROOF

I showed the repairs we did on this "never installed" carbon roof but in mid-July it was time to mount this to the chassis. We used our knock-off brand 3M panel bond and Christian scuffed up the edge on the bottom side of the roof that bonds to the chassis, and of course the mating chassis side also.

A squirt of the 2-part panel bond, carefully placed down by 2 people, then a bunch of clamps to hold it for 24 hours - and it was done in no time.

We had the four aluminum blocks and four factory bolts holding it down also while the panel bond set up also. When it comes time to paint the car we will bodywork the carbon panel smooth and fill in the channels on the sides with OEM bits that we will panel bond in place (after they are painted).

GIANT HOOD VENTS (IE: HOLES!)

It was mid-July at this point and the cross engine brace hanger was finally removed, as Matt had finished the headers and the new motor mount. So we could close the dang hood for the first time in almost 8 weeks! This is when we were able to take a look at the Seibon Carbon hood with the "GTR" style vents removed.

The 2.7 pounds of louvers were just unbolted, as they are made separately from the hood. We contemplated cutting the thin bridge out on each side but I kinda like how it looks.

And from some recent testing we have seen Nine Lives Racing do, the "giant hole" flows more air than the much restricted louvered covers allow. With as much air as we have shoved into the engine bay, we could use the flow. Not everyone will agree that this works better, and we kept the louvers for an A-B-A track test with these in and out. For now we plan to make a short Gurney flap ahead of the leading edges of the "two" big openings and run it as-is.

FITTING REAR BODYWORK

I have been devoted to the "big tires are better" theory for 35+ years, and I never shy away from going wider than anyone else in class - and it has paid off, every single time. Our E36 M3 was one of those cases where we managed to fit 315/30R18 tires onto a 250 whp E36 with over-fenders that even the manufacturer thought "there's no way that will fit".

It worked so well I doubled down on the Fitment Lab brand for the rear over-fenders for our E46. And at this point in the project, I was itching to go from "mockup" to really installing the rear fenders. There were other tasks that had to key off of these, so Christian hopped on it and began mounting these - just like he did the E36.

I am all about removable bodywork whenever possible, so these were drilled and mocked-up in Clecos then we moved to M5 rivnuts and bolts. These Fitment Lab fiberglass over-fenders needed to meet up with the Flossmann rear bumper cover and side skirts, and we held our breath - but the rear bumper cover was flexible enough to line up perfectly. The Flossmann bits allow for a lot of rear fender pressure evacuation, too.

Just like he did on the E36, I asked Christian to move the BMW fuel filler door out flush with the over-fender. Otherwise it sits inboard about 3/4" and looks funky (see above left). Well the opening flares out so he moved the click-latch and hinge outboard to flush mount the door.

The opening was larger so he made an aluminum outer skin and grafted that to the OEM fuel door, and it lines up flush and still functions like stock: to open the fuiel door you press once and it pops out, then you swing and latch it back when you are done fueling.

A little bit later Brad had some time and replaced the temporary Cleco fasteners M5 rivnuts and button head stainless bolts. This will all look better when it is painted red, trust me.

CHASING POUNDS - GOOD BYE WIPERS!

After we took that June 10th weight we started getting more serious on chasing weight. The wipers and motor are not needed in Max2 class with Level 3 Safety, and the chances of me ever taking laps in Time Attack when it is raining hard are ZERO. So that was 7 pounds that Brad removed in arms, linkages, and motor.

Meanwhile we were hacking up and weighing the first OEM dash that would be used in this car. This one was used for mockup and had too many chunks missing, and we would go through two more before I was happy.

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**Fair!** · 09-03-2026, 04:22 PM

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DRIVESHAFT ADAPTER MACHINED AND INSTALLED

BMW loves using a driveshaft bushing to connect transmissions to their 2-piece driveshafts and they tend to have 6 bolts - 3 for the transmission side and 3 for the driveshaft side or "prop shaft". After some measuring with a stock E46 M3 driveshaft, which bolts to the 210mm "large case" E46 M3 diff at the back, we felt like we could make up the difference in length AND adapt the two unique bolt circles for the E46 driveshaft pattern and E92 DCT's bolt pattern

I bought the black import "Guibo" which replaces the rubber flex disc with an aluminum unit and 6 polyurethane bushings and sleeves. We then measured the thickness we needed to make up and the two bolt circles and Arturo designed this dual pattern adapter. I assembled it with the poly bushings and sleeves from the import kit and it worked exactly to plan.

This now bolts to the E92 DCT transmission output flange and to the E46 M3 prop shaft. The center bearing is bolted to the chassis as it should be and out back we have new hardware to attach it to the E46 M3 differential input flange. We will keep an eye on all of the hardware and such but I think we got pretty lucky on this adaptation and for once did NOT have to spec / order / buy a custom driveshaft. That is a huge win!

CHARCOAL CANISTER AND VENTING

Gas tanks in cars have to hold liquid gasoline that expands in the heat, and thus release pressurized fuel vapors. As fuel is consumed during use, air has to come back into the tank otherwise the vacuum created will cause the tank to collapse. A two way valve is then needed in the gas tank, at the top, to allow for this passage of vapors out and air back in. In 1971 US automakers were required to have this vapor go to a charcoal canister, which traps much of the fuel vapor, and thus smell. Some cars have a purge valve that allows the vapors to get burned in the engine. None of that exists on our $100 E46 chassis we started with for this project.

On the E46 it is a huge charcoal canister mounted next to the spare tire well, which is long gone. I will admit that I can go a bit overboard making our cars "not stink like fuel" from vents to atmosphere, but I hate when we have a gas tank that isn't properly vented into a charcoal canister. If left parked inside of a trailer for even a few hours, the fuel vapors from most race cars will stink out the whole trailer and car. Lately we have been venting gas tanks to a custom charcoal canister we make for about $40 in materials, as shown above. There are kits you can buy from Radium Engineering that start at $260, but they don't really do an more than what we have built for $40 and used successfully on a few cars.

On our Fox Mustang with a 6.3L V8 we first built one of these and mounted it inside the trunk, with its own external vent behind the fuel filler door - outside of the trunk or cabin. That car has zero stink and I love it. On this E46 fuel tank there are 3 places that air and vapors can pass in and out of the stock tank, and there are discriminator valves for these spots.

We took all of those hoses and plumbed them back together into our charcoal canister, which is mounted behind the car. We start with one of those cheap "catch can" kits made for crankcase pressure. These are too small for that use, but do work well filled with charcoal for a fish tank filter as a charcoal canister. The kits tend to come with lots of fittings and an external air filter, which we put to use.

Once we have configured the can and filled it full of charcoal, it gets placed outside the car - or at least the air filter does. This needs to be above the highest part of the fuel tank, of course. On our E46 is is above the rear bumper, as shown above. It bolts to the chassis and the hose goes to that jumbled set of hoses that connect to the 3 ports on the tank shown. We could have spent $260 on the fancier Radium unit, but these work great with the parts we purchased - and we started with enough charcoal filter pellets for about a dozen of these.

REAR BUMPER BEAM + BUMPER COVER MODS

Speaking of the rear bumper beam, we had some changes to make. See I originally had a crew make this 13.9 pound tube bumper back in 2022 as a full width, wrap around bumper beam for a W2W car, which was the original intent of this chassis (endurance racing). It had my favorite double tow hooks out back and fit the stock E46 330 rear bumper cover. If we tore up the rear cover in racing those were cheap to replace, and the full width wrap around style better protected our rear fenders and tires from W2W carnage.

Well the E46 is now a Time Attack car with a Flossmann rear fiberglass bumper cover, so some changes were needed. We no longer has the W2W issues and could afford to build around the costly Flossmann fiberglass unit. But we definitely didn't need the integrated fiberglass bumper beam structure that the Flossmann kit had.

Brad started mocking up the Flossmann rear cover and then cut away all of the added weight and structure they add for street cars, as this is made to replace the OEM bumper cover and crash bar. Lots of pounds were chopped away, and then it was fitted over the bumper beam we built in 2022.

We had to cut off the tow hooks and make some changes, as the bumper beam moved a good bit further back. Matt also convinced me to cut the wrap around bits, and several inches were removed since this is no longer a W2W bumper.

Christian had mocked up the Flossmann bumper cover (after the over-fenders were fitted) and Brad jumped in to add some blue tape. To this he marked out the lateral location of the factory frame rail, then measured the height he wanted the tow hooks. That slot was laid out then carefully cut out with a small air powered body saw to fit the 1/4" thick tow hooks.

We CNC plasma cut out some our common tow hooks with 2" ID holes that were then fitted to the bumper beam through the fiberglass cover. Those were trimmed to fit the slot locations, then tack welded on, the bumper cover was checked, the slots sanded for a perfect fit.

Christian also added some steel plate as a gusset for vertical loads, based on what we have learned from using these as trailer tie-downs. The length and gussets should work great. This is all very fiddly work and takes time, but the results are worth it when you can dial in the bodywork perfectly to the protruding tow hooks. It looks like they barely fit through the slots - which they do - and that is what we want.

FIRE SUPPRESSION SYSTEM INSTALL + COOL SUIT COOLER MOUNT

It is late July 2026 now and there are a number of things we needed to find a home for inside the E46 chassis. The fire suppression system and cool suit cooler are fairly large, but they need to be accessed every event - I need to pull the fire system pin to activate the pulls, and I will be replacing ice / water inside the cooler once or twice per track day. The ability to easily remove the whole ice chest makes dumping the water out after an event much easier, too.

Many times we would put these two devices in the trunk, but as you can see above - our wing location limits the trunk opening. We could fish out the cooler and get in there to pull the fire pin, but since we won't have a right seat in this car, we decided to put these two devices where the right seat would be. Again, see my section on the NOCO battery placement. Having weight here (low and central) is a pretty good place for "ballast".

Brad made the mount for the cooler first in cardboard. Now if I wasn't tied up I would have scanned this and then CNC plasma cut this out, but he got this done pretty quickly the old fashioned way - cutting it out by hand, then bending it up. Above right he is shown laying out dimple die holes, which add stiffness and remove weight. We made from thin .063" thick aluminum sheet to save weight.

It took a couple of hours to finish out the bracket but the total weight was under 2 pounds. After the dimple dies were finished we discussed where to add a hand held fire bottle mount right on the front.

We sell this Safecraft PB3 3 pound Halon style fire bottle (which you can see weighs 4.7 pounds - it has 3 pounds of suppressant), and I like to have this in all of our track cars as the bare minimum. Even with a full multi-nozzle system, this hand held unit on a quick disconnect mount like this Drake Offroad unit. We mounted that on the front edge of the cooler mount, like we often do in front of a passenger seat on the seat bracket base.

This layout worked great, as I can reach over and pull the fire bottle pin from the driver's seat if I forget to before a race day (it has happened!) and if we ever want to swap in a seat we can remove the cooler mount and still barely fit that in place. The whole 18 Liter Paragon cooler, Paragon cooler aluminum mounting tray, Safecraft fire bottle, the Drake QR mount for that, and the mounting tray Brad built only tips the scales at 16.4 pounds.

Now while all of that was being built Brad also mounted the Lifeline Fire Suppression system, which started with the Lifeline bottle mount. Then he plumbed the included aluminum tubing and fittings to run forward to the firewall, where it "Tees" off to feed the engine bay and - in a short while - will feed two nozzles pointing at the driver.

The two nozzles in the engine bay point towards the fuel rails. We also have a fire line pointing towards the trunk, where a nozzle will be above the Radium surge tank and all of those fittings there. For now, the fire bottles are mounted, as is the driver system cooler.

NEW MOTOR MOUNT

One of the many frustrations of these complicated long tube headers was that we had to ditch the previous mount on the left side, to gain more header room. Matt made this one from a CNC cut plate that mounts to the S65 engine block as shown below. I actually like this design better than before.

The typical Vorshlag LS swap mounting bushing is sunk into the plate, which fits into a large pocket on the block. This gained much needed room near the steering rack, as shown above right.

The rest of this 2-piece engine mount is made like our LS swap mounts, with tubular parts and then it was painted red. One piece bolts to the block the the side with the bushing mounts to the subframe.

LEXAN REAR WINDOW SLOTS FOR WING UPRIGHTS

We had a Lexan rear window cut for the E46 from before we restarted the project with the S65 swap. The uprights coming through the back window is challenging to cut out, so I asked Christian to make a template out of cardboard from the Lexan window. After measuring out where he thought the slots should be, he cut those out and put the template in place. Those were in the upside down position, so I suggested cutting a BIG hole and sneaking up on the final slot with blue tape.

That method worked and was transferred to the Lexan window. The cuts were carefully made and cleaned up and file fit to the uprights. Once that fit the window was slid over the uprights for the last time by Brad and Christian.

We left the protective outer film on for a bit but a few weeks later that was peeled off and the AJ Hartman carbon wing + our end plates were installed. And that made me very very happy.

MAKING ROOM FOR FLOSSMANN SKIRTS + MASSIVE TIRES

Part of the FLossmann widebody kit that came on the E46 328Ci we sold earlier this year included these crazy side skirts. They tie into the front fenders and need to be merged into the rear flares. The front fenders vent through this skirt but they need a lot of room to fit. We looked at the 328Ci that we sold and we copied that work on our black chassis here.

We needed this same room to swing the 18x12" wheel at full lock, so we started cutting. We tell customers all the time - don't be afraid to cut the chassis to clear big tires, because tires matter a LOT. After the corner was chopped off a piece of 18 gauge steel sheet was cut to fit and stitch welded to the tub.

After the welds were finished some seam sealer was added to weatherproof the whole patch. That was allowed to dry overnight and the next day it was painted with zinc based primer then some black paint.

Now the side skirt could actually be fitted up to the chassis. This was done a number of times when the cut was being made, and then he cut some more, test fit, cut some more.

The right skirt was cut up for side exit exhaust, which was why we didn't use that 328Ci chassis - the floor was ruined. Christian got to work laying up fiberglass mat and resin. After a few layers, glass filled filler was added then smoothed and painted it white. Perfect.

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**Fair!** · 09-03-2026, 04:26 PM

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The Fitment Lab rear over fender and the skirt wanted to occupy the same space, so Christian modified both parts to play nice together. This happened so quickly I didn't even get any pictures, but they somehow look like they were always meant to go together!

In the picture above left you can see how much venting there is into the front fender wells, and that is pretty impressive. I suspect we will need to trim these inner vents to clear the tire at full swing, but we had the wheels off for a while here and will get to that shortly before the first test drive.

STEERING WHEEL HORN BUTTON + 12-PIN WIRING

This was a weird one. So we showed the NRG hub, MOMO wheel and Domiworks paddles shifters in the last update, but I found out that we have been putting the horn buttons into these wheels incorrectly. Since then we have moved over all of our cars to the NRG Quick Release hub, we use their 2.5 version as it allows for a 2 wire pass-thru so it can have a working horn.

One thing we always fight with are the horn buttons, which don't seem to snap in correctly with any of the QR hubs we use - but then I watched a YouTube video that showed the right solution. #YouTubeCertified

What that video showed me was this unique horn button retainer ring made for the NRG QR hub, and at only $9.40 each I bought a few. There is one tab that has to be bent out of the way and then this totally fixed our issue. We've since rolled out this fix on 3 shop cars with the same QR hub and wheel, yay! No more horn buttons falling out of wheels.

We are using 2 additional buttons on the Domiworks 4-button mount to control for "flash to pass" and "radio" transmit, which each have 2 wires. We also have the 2 paddle shifters for an additional 4 tires. We needed 8 wires so I ordered a 12 wire curly cue cable from Motec, and Brad had the fun job of wiring that up. We were thinking at the time about how to secure the 12 wire cable, so he made this aluminum bracket shown above that bolts between the NRG hub and the MOMO wheel and Domiworks bracket. It is too thin to matter for wheel depth.

With the 8 wires terminated and routed, Brad secured two pairs on each side together and the whole 12 wire bundle is secured to the aluminum bracket, as shown above. It is super clean and the curly cable comes out of the bottom of the wheel, as shown above.

This should make for a durable setup that will connect to the dash with a 12 wire connector, and we will have some sort of cable guide to keep it from dangling down on my leg while driving.

BREMBO FRONT BRAKE UPGRADE

In the last update I talked about big brake options and we had settled on this used AP Racing Pro5000 caliper and 325mm AP rotors with aluminum hats I got them really to use on our BMW E30 (which is sub 2500 pounds) and honestly that is a more appropriate use case for these. They are light, but as I mused last time, I really wanted a 355mm rotor on this E46 - with this weight and power level.

After I stumbled upon an E46 M3 / Z4 Brembo Racing kit for a great price, which is a 355 x 32mm rotor and massive 4 pot front caliper AND crucially, the mounting brackets and unique brake lines needed for this swap (plus pads we won't use). Making these brackets and custom lines, that were missing from the pile of AP part above, was going to set back our schedule so this Brembo upgrade was also a big time saver.

These things are just so beautiful so I weighed and took pictures of every aspect of them. Got weights of the rotors (19) and caliper + bracket + pads (11.6), and they go together like many Brembo calipers. The steel bolts that hold the caliper together are what gives them good pedal feel when up to temperature, as aluminum gets a bit elastic the bolts keep the housing rigid.

Assembling the kit was super easy and Christian had it all together in like 45 minutes. We didn't have the factory E46 M3 caliper bolts on the spindles, which were tough to source, but digging through our used BMW parts he found 4 of them on another set of spindles luckily.

Our new and improved E46 front brake cooling deflector kit fit without any modifications. The whole package is just really well built and I am sure we'll enjoy braking with these more than with the smaller AP brakes on this car.

We ordered G-LOC pads for the front and those arrived a couple of weeks later. Out back we used a Powerstop OEM replacement kit for an E46 M3 for now, as that was the most cost effective way to get new rotors, calipers and mounting brackets.

Yes I know that drilled rotors are a dumb car show thing that comes from 1980s brake pad limitations, but they came with the kit and were fully coated. I have another set of new M3 rear rotors we can use when these crack.

Matt here at Vorshlag is also building an E46 M3 (S54 powered) and is fitting these massive rotors from an F80 M3 (which is hugely heavy but capable chassis). These are around $400 each and are co-cast 2-piece pin drive rotors which measure 380 x 24 front and 370 x 24 rear. If we are killing the E46 M3 rear rotor we might upgrade to this F80 M3 rear, who knows?

WHAT'S NEXT?

Wow, this update got a bit long, but it almost caught us up to work in real time - covering work up through July 2026, which is pretty close. Right now as I write this in early September we are close to starting the engine and my next update will show that, plus dyno testing and the car's first laps on track. Next time we can talk about the dash work, exhaust that was built, final wheels and tires, and other final build aspects.

I will admit this is the most time and money I've ever spent on a $100 chassis. I was supposed to be saving money starting with a cheap shell, remember? Honestly these swaps do give us a combination of power (S65), superior shifting (DCT), and light weight (E46) that no one single chassis built by BMW could ever gave. So it makes sense for us to build these swapped combos, but it doesn't make sense for everyone! Remember that when you follow along - swaps are hard, and they can serve a purpose - but saving time or money isn't usually it.

Cheers,

Terry Fair @ Vorshlag

Announcement

Vorshlag "E46 M3 GTR" : S65 V8 + DCT swapped SCCA Max4 Time Attack

Vorshlag "E46 M3 GTR" : S65 V8 + DCT swapped SCCA Max4 Time Attack

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