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!** · 2026-02-13T17:40:23

Project Update - Feb 13, 2025: 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!** · 2026-02-13T17:42:29

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!** · 2026-02-13T17:45:09

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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!** · 2026-02-13T17:47:48

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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!** · 2026-02-13T17:53:17

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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

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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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