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Vorshlag Miata LS1 Alpha Project

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  • Vorshlag Miata LS1 Alpha Project

    New Project Introduction : Many of you reading this already know about Vorshlag's history with installing American V8s into European sports coupes and roadsters, but that wasn't the first V8 swap that I contemplated. Back in 1998 I purchased a 1992 "NA" 1st generation Miata. I bought it wrecked, repaired all the bodywork, and had it painted with the intention of building a 302 Ford V8 powered "monster" Miata. That was right around the time when the LS1 engine was just being introduced into the new 1997 C5 Corvette and 1998 Camaro/Firebird.

    Note: To help me keep track of which forums this build thread is cross-posted, I have made this list...

    A couple of BMW E36 chassis with our LS1/T56 swap kit, shown above. These can weigh 2550 lbs (without interior) to 3100 pounds (fully optioned)

    At the time I owned this '92 MX5 we were moving from Houston to Dallas, so the Miata V8 swap was mostly ignored, then became a seldom used daily driver for a couple of years. During that time I also owned and raced an LT1 V8 powered '94 Corvette and a supercharged LT1 '94 Trans Am, but I noticed quickly that the all-new "gen III" small block Chevy LS1 engines were a cut above the "gen II" LT1 motors. Deep skirted all-aluminum blocks with 6-bolt mains, incredible cylinder heads, and lots of new technology - but the same narrow/compact architecture of a "cam in block", pushrod V8. I was quick to get my hands on LS1 parts, weighing blocks (109 lbs) and heads (21 lbs) and learning quickly that these things are very light. And they were making more power, dollar for dollar/mod for mod, than anything else out there.

    Comparison of Miata drivetrain next to LS1/T56

    We completed the move from Houston to Dallas and the plans for little Miata V8 project switched from Ford 302 to Chevy LS1 V8 power. I started to accumulate LS1 bits, but the Miata (one of a half dozen cars I owned at the time) was parked outside and got hammered badly in a hail storm. This was a big one - it blew out skylights, ruined our gutters and roof, and utterly destroyed two of my cars. I was "SOL" and sold the Miata for a bit of a loss. My V8 swap fascination changed focus to a BMW E36 with LS1 power, and in 2002 that project began with the same block I had rounded up for the Miata. Since then we've sold dozens of E36 BMW LS1 swap kits, made an E30 BMW LS1 (our $2011 GRM Challenge winner), Z3 LS1s, and are deep into a new E46 chassis LS1 swap. We have several E36 LS1 turn key swaps underway right now, too.

    Even Mazda knew the 1.8L wasn't enough. Here's a factory built NB test mule with a Duratec V6. Why was this never built?

    But this whole time that Miata LS1 swap was bugging me. It was an unfinished project that I had let slip by. A thorn in my side every time I saw people talking about the various LS1 Miata kits out there. Sure, the V8Roadsters LS1 swap kit sold by Flyin Miata looks very nice, and the new Boss Frog kit has a different take on it. They have fine products and I am not saying otherwise. But... I could see little improvements we could make, significantly different parts choices I was familiar with from my years of building/owning/racing Corvettes, F-Bodies, and Mustangs, and maybe some improvements that could come from our decade of working with LS1 V8 powered BMWs. The question I put to myself earlier this year was: Should we jump into this market with our own LS1 swap kit for a Miata??

    Yes, we are making an LS1 swap kit for Miata's

    As you might have guessed, we are going forward with this swap. Why would I start this thread if we weren't, right? Our BMW LS1 swap business has been growing lately and we have been taking on turn-key swaps in addition to the already robust E36 LS1 swap component manufacture and sales. We all love this Miata chassis, it is so abundant that it has become very affordable, but they are just... lacking in horsepower. An LS1 fixes all of that.

    Our first Miata V8 candidate, or "Alpha" Miata, is a 1999 "NB" 2nd Generation Miata that weighed 2342 lbs with 1/2 tank of fuel

    For now, we are going to concentrate on the 1999-2005 NB chassis and skip the 1990-1997 NA cars, just because they are getting a bit long in the tooth. The prices aren't that far apart for clean swap candidates, looking between the NB and NA Miatas. The 3rd gen NC MX5 chassis is significantly different from the NA & NB cars, and used car prices are still pretty high, so we are not going to delve into an NC LS1 swap right now.

    Left: Miata "BP" 1.8L engine weighs 348 lbs. Right: Miata 5-spd manual transmission weighs 85 lbs

    Some of the weights involved are shown above and below, from weights we have taken. Looks like the 1.8L Miata motor and 5-spd trans together weigh 433 lbs, with accessories. Not bad for an iron block 4 cylinder. By comparison the BMW E36 chassis' 4 cylinder M42 DOHC 4 and Getrag 5-spd are 429 lbs, which is almost identical. The big 5.7L LS1 V8 weighs 457 lbs soaking wet, with all accessories (and has more than triple the displacement and triple the power of the Miata 1.8L). The 6 speed Tremec T56 (from the 1998-2001 Camaro) itself is a portly 125 lbs, but it's a big strong transmission with two overdrives. That should give us a 582 lb drivetrain, if we stick with the T56, or an extra 149 lbs over stock. The combined "609 lb" weight shown below was indeed for an LS1 and T56 drivetrain with accessories, but also included a stock Camaro engine harness, MAF sensor, and engine computer.

    Left: The M42 1.8L DOHC 4-cylinder and Getrag 5-spd is 427 lbs. Right: A fully dressed 5.7L LS1 + T56 at 609 lbs (click to enlarge)

    Why do we love the LS1 V8 so much? Well, there are several reasons. It is a compact and light engine, as I mentioned before. It has been used in literally millions of cars and trucks worldwide since 1997, in so many variants - iron and aluminum blocks, and factory displacements that include 4.8L, 5.3L, 5.7L, 6.0L, 6.2L, 7.0L - that are all dimensionally identical. With aftermarket support that dwarfs almost every motor in existence, there are essentially no limits on power goals, which aftermarket engines that can make 8.5L and boosted engines pumping out 2500 hp. A common build is to use a nearly stock aluminum 5.7-6.2L LS1 series engine and make 350-450 whp, with a mild camshaft, good street manners, and great power under the curve. Even "only" 350 whp in a 2500 pound package can be a total blast at an autocross or track event. A little more displacement and/or compression+camshaft can get you to 500 whp, which is a LOT of fun.

    Our first steps included finding a willing Alpha customer, which we found in Jason Toth. He was eager to become our first test customer and on his own he rounded up this highly optioned, 1999, silver 5-spd Miata that needed a little help and wasn't anything super rare, so it will make a great swap candidate. Once the car was here, we took a ton of measurements and fixed a few little things on the chassis that were going to stay. Then the OEM drivetrain was pulled out so we could take a closer look.

    The car was coated in oil underneath from a leaky front seal, so we gave it the full pressure wash treatment under the hood and on the bottom. Once the car was in the air I noticed the relatively large transmission tunnel, so I was pretty confident we could make the Tremec T56 or something like it fit without too much trouble. We might go another direction with the transmission, with two other possible gear box candidates, but I will share more on that soon.

    First test fit of our mock-up LS1 and T56 transmission

    Once the stock drivetrain was out, we shoved our "mock-up" LS1 engine and T56 into the little car. The initial fit wasn't half bad, but there are two corners in the firewall that really limit rearward movement of the V8 engine's cylinder heads. Our guys cut some small notches back there (which will be covered in steel when the final engine placement is locked down) and re-installed the LS1/T56 drivetrain farther back, and now it looked much better.

    Well we're committed now! You can see the corners we trimmed to make the LS1 fit farther back, which lines up the shifter nicely, too.

    After seeing this second test fit's engine placement, we were happier and now know which oil pan should work perfectly. We've also got a good idea on how we want to build the new front crossmember, which will be a custom tubular design utilizing mostly stock suspension geometry. Definitely some weight to be lost there. The rear differential was also mocked up with an aluminum Ford 8.8" 31-spline differential carrier from a 2003-04 Cobra. This will need another custom subframe to mount this diff carrier, plus some other parts we will discuss later.

    Vorshlag LS1 Swap Goals

    I don't want our kit to be just another "me too!" option for the Miata V8 swap world. Although some of the steps and parts will be similar to the other kits out there, we plan on doing several things very differently. In order to make the drivetrain work how we want, some of the major changes will have secondary effects, including some upgrades to other areas of the car. These "forced" upgrades will work in harmony with the rest of the swap to keep up with the speed potential of the ~400 whp LSx powerplant that most customers want. Again, these upgraded components will be shown as it they are developed.

    The factory NB Miata Power Plant Frame is shown in the pictures above (click to enlarge)

    One major change I proposed was trying to keep the factory Power Plant Frame (see above), which is the big aluminum C-channel shaped structural member that attaches between the factory Miata transmission and rear differential carrier - giving the chassis much needed rigidity. All of the other V8 swap kits do away with the factory PPF and replace it with big slabs of steel in the form of subframe connectors, and another big hunk of steel that bolts between those to become the transmission crossmember. My initial idea might not work, but we're going to try it - as keeping a PPF could both save weight and keep the chassis stiffness using the same style components the Mazda engineers started with.

    In the end, I want to see a 2500-2550 pound finished weight on this fully optioned, full interior, street car build. That means only +150-200 lbs total weight added over stock. And yes, if you are keeping up with my math that's barely enough added weight to cover the increase in drivetrain weight over stock (+149 lbs), so we have some weight loss to concentrate on. That's what makes this swap worth doing - light weight, lots of power, small car. I am hoping that the custom PPF, our tubular subframes, and some of the other potential differences on our proposed LS1 swap kit will help save some weight over the Boss Frog (+300 lbs over stock ) and V8Roadsters (+200 lbs over stock) swaps. Who knows - we might miss that goal, but we are going to try. Again, we're beefing up some other systems (that might add some weight on their own) to match the performance of the LS1 engine that most other kits completely ignore. Only way to know is to try our ideas and scale the parts continuously throughout the build. Every stock piece that comes off will be weighed and so will every part that goes back on.

    Sharing The Build Online

    As usual we will post updates on this project and share them with the online community during the Alpha build. Perhaps it is not smart to show our project this early in developmental stages, but that's how we've always done it. In the end, we always get good ideas from forum readers, as there is always someone out there that has run into something we might not be familiar with. We do have some very experienced Miata guys in house, as well as good fabricators and a decade of experience in the LS1 swap world. It would be foolish to think that "we know more than everyone", and we can always learn something from someone. If you see something that could be done better - feel free to speak up!

    Since some of my ideas might crash and burn as we progress, I'm not going to give away all of our thoughts up front. Some will become obvious as the build progresses, and whatever we end up with will have tons of pictures and data shared along the way. We also reserve the right to change directions on a particular goal, part choice, or theory as we progress - because on this first build I am sure we will learn as we go. Whatever we do, we will try to post regular updates as the build progresses.

    When Will It Be Done?

    This is a question I hate answering, because the answer is vague: "It will be done when it's done". There are so many things going on at the Vorshlag shop, which is a company primarily focused around developing, building and supporting suspension products. The LS1 swaps are too much fun so we also spend a good chunk of our time building, developing and supporting these swaps now, too. We are already well underway on a new BMW E46 LS1 swap kit & Alpha build, have some new things coming for our BMW E36 LS1 swaps (as well as three turn key builds), and more.

    Just know that this Alpha LS1 Miata build is not going to happen overnight. This is not a "one-off" build and it has the extra burden of a future production swap kit riding on it as well. We will take what we learn in this build to create production fixtures so we can manufacture parts in batches made to tight tolerances. Then anyone with some basic tools can use our kit parts on their NB Miata, install them in their own garage, and have them fit without major hassles. The users and production variables dictate how we can implement some of our V8 swap solutions, as always.

    So if you absolutely gotta have a Miata V8 right now, then we aren't your source. Check the links I have included above for the competing LS1 swap kits, which are in production today and I'm sure they'd love to have your business. I'm going to stop here, as I have four other build threads to update or start (Pikes Peak STi, BMW E46 LS1 Alpha LS1, McCall's BMW Z3M LS1, and the Subaru BRZ build thread).

    Last edited by Fair!; 12-18-2014, 03:13 PM.
    Terry Fair -
    2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
    EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev

  • #2
    Re: Vorshlag Miata LS1 Alpha Project

    I’m going to be following this build thread with a lot of curiosity. Since there are other companies already offering this swap, it will be interesting to see what you guys can bring to the table.

    That said, when it comes time for the inevitable next LSx swap candidate for Vorshlag, I’d like to suggest an S2000 – the chassis is infinitely more rigid than an NA/NB Miata, it has better brakes (along with standard factory ABS – something that is extremely rare on NA/NB Miatas), and it can fit significantly more tire than an NA/NB. Prices on good early AP1 S2000s are very reasonable as well.

    To me, the limitation on wheel clearance is the biggest Achilles’ heel of the Na/NB with a big power swap. Still, good luck and I’m interested to see what you come up with!

    '01 Honda S2000 - extra crispy
    '05 Honda CR-V EX AWD - alphabet soup family truckster
    Always looking for a co-drive...

    "We don't stop playing because we grow old, we grow old because we stop playing." - George Bernard Shaw


    • #3
      Re: Vorshlag Miata LS1 Alpha Project

      Project Update for October 1, 2012: Well we've had a busy few weeks since the last update, after the blur that was August (Pikes Peak hill climb event), spending September racing at the SCCA Solo Nationals, a Global Time Attack event, and some other autocrosses. But the LS1 Miata project hammered along with a few test fits, some changes, new parts arriving, and key decisions being made. We acquired several donor parts, weighed and tested each of them, and whittled down our options quite a bit. Let's get caught up:

      Three Transmissions, One Winner

      The transmission to use in this chassis was always an unknown. The tunnel is tight in some areas and we didn't want to require our end users to hack up the tunnel in their cars to fit the transmission. A little engine bay trimming isn't so bad, but slicing and widening the tunnel is major work that most people do not want to tackle - us included!

      The first manual transmission candidate we tested with was the Tremec T56 6-speed transmission. This one is very well known, but with increasing demand and a finite supply from the 1998-2002 Camaros and Firebirds, the used prices have been creeping up towards $1500. The T56 "Magnum" (really just an aftermarket version of the 2010+ Camaro's TR-6060) is around $2800 new, but has increased torque capacity to 700 ft-lbs among other needed improvements. We used one of these in our E36 "Alpha" car behind a 490 whp 7.0L LS2 and it was a great trans. The Miata fitment testing we did on the LS1 + T56 fit "pretty well", but still had some width limitations inside the stock NB chassis' tunnel. We really do not want our LS1 swap kit to require tunnel surgery and we want the engine as far back as possible, so this gave us reason to think twice.

      1998-2002 GM F-Body T56 weighed in at 125.8 lbs, dry.

      The T56 also didn't have an easy way to attach the Power Plant Frame ("PPF" or Torque Arm) to the rear end. Also, this transmission is relatively heavy at 126 pounds. It is a great transmission, capable of handling some good torque (450 ft-lbs), shifts well enough, but has two overdrives... which is overkill for this chassis.

      Next up, we purchased and tested with the ZF S6-40 6-speed manual from a 1989-1996 Chevy Corvette. This "ZF6" is a freagin' TANK of a transmission, used in several BMW models (with a different tail assembly missing the PPF mount) with either 650 or 1000 ft-lbs of torque capacity in stock form. It also has a provision for a very similar torque arm as the Miata, as used in the C4 Corvette. That was my favorite choice up front, but as some of you pointed out, it has a few flaws.

      1989-1996 Chevy Corvette ZF S6-40 weighed at 153 lbs, dry.

      First is that weight! Good grief this thing is heavy, even using a factory magnesium C4 bellhousing. That big torque rating comes with a lot more steel on the internal gears. It also has a divorced shifter that mounts to the body, unlike the T56 which has an internal rail shifter (which makes for better shift feel and easier swapping). We found a good specimen with a magnesium bellhousing made for the LT1/LT4 engine, but it was going to take an expensive adapter plate to mate to the T56 bellhousing made for the LS1 engine - and it would only gain weight.

      The shifter location was not right and the clearance to the tunnel was non-existent.

      Finding the ZF S6-40 new is impossible, as they have been out of production for over a decade. Finding them used is difficult because they only came in certain C4 Corvettes and rebuild costs were also high. Physically the remote mounted C4 shifter location was way too far forward and the transmission itself was WIDE. There was no way this big beast was going to fit the Miata tunnel without a major fight. The only feature it added was the potential to use a modified C4 PPF, but that was not enough to overcome the many other obstacles. So the ZF6 was a dead end. Hey, you sometimes have to try something to find out what works and what doesn't. We had seen weights listed all over the place, and now we know.

      Yes, some of you figured out this was the transmission I eluded to in my first post, and yes, you were right that it is not a good swap candidate. I am not always correct.

      Our third choice was the Tremec 3550/TKO series 5-spd, and I think we have a winner. This 5-speed has an internal rail shifter and only weighs 95 pounds, but the two aftermarket TKO versions have 500 and 600 ft-lbs of torque capacity. They are hard to find used, but only cost $2200-2300 brand new. Of course it has no provision for the PPF, but I have pretty much given up on this as an impractical goal. Sure, we could hobble together something that attached to the back of the TKO, but we already have enough custom fabricated parts in store for this swap to make all of our other "wish list" items work.

      We have seen these TKO's in all manner of race cars and kit cars, including a Cobra with a Ford big block that was in our shop for some work for about a week. We got to measure the trans, drive it, and this trans is pretty slick. It is so compact, yet so strong! The only question left was which aftermarket version to use?

      TKO 500 vs TKO 600

      There are actually 3 choices when it comes to the GM pattern Tremec TKO transmission. The differences in torque rating and costs all come from some internal gearing differences. But there are key reasons why we want to use the 600:
      • Tremec TKO 500 Chevy/GM - TCET4616
      • Transmission is rated at 500 lbs. ft. Torque
      • 3.27, 1.98, 1.34, 1.00, .68
      • Tremec TKO 600 Chevy / GM - TCET5009
      • Transmission is rated at 600 lbs. ft. torque
      • 2.87, 1.89, 1.28, 1.00, .64
      • Tremec TKO 600 Chevy / GM Road Race overdrive - TCET4618
      • Transmission is rated at 600 lb-ft. of torque
      • 2.87, 1.89, 1.28, 1.00, .82

      When you look at the ratios the "normal" TKO600 actually has a much more usable first gear for a car like the Miata. That tall first gear works better when you are using these transmissions in a light, powerful car with not enough tire (we won't ever have "too much tire" on these cars, heh). Way back when I was racing a Mustang 5.0L with the factory T5, it had "3.35" first gear. Later I went to a T5-Zcode, which had a taller "2.95" first gear and the change was very noticeable. The taller 1st gear was much easier to launch with at an autocross and the gap between 1st and 2nd was closer - for a more normal feeling gap. This TKO600 looks like that same upgrade over the TKO500.

      So the TKO600 is where we would go, just for the better first gear. It also has a slightly taller 5th gear, for better highway cruising. There is also a TKO 600 "road race" version which is the same box, with the same taller first gear, but a lower 5th gear, for using all 5 gears in anger on a road course (much tighter ratio 4th to 5th). We don't think there's any road course where this would be needed on a Miata with a big thumping V8, and it wouldn't have as much of a "street friendly overdrive" as the .68 or .64. So the TKO600 with the .64 5th is what we think is ideal.

      The TKO's synchros are big beefy brass units, which are a bit unusual in construction; we have heard stories that they don't shift well above 6500 rpm, but then other racers using them say they work fine. We talked to a local Tremec rep that came by our shop last week and he said he can make these TKOs with a custom carbon blocker rings and synchro package so that they will shift like butter at high RPMs. For this build the engine we have in store isn't a super high rpm buzz bomb and will likely make peak power at 6000, so this isn't a concern this time.

      Other Parts In Store

      We are still exploring possibilities with the rest of the swap, but we do know the Ford 8.8" aluminum IRS differential housing from the Ford Mustang Cobra is what we will build the back of the car around.

      Left: The BMW E46 188mm diff next to the aluminum 8.8" Ford. Right: RX8 front parts (top) will be used, but the rear uprights are 5-link and wrong (bottom).

      Development on the front end is starting with a pair of Mazda RX8 uprights and hubs. These feature 5x114.3 bolt circle hubs, with much stronger hub assemblies than the 4 lug Miata. The uprights are nice aluminum units which we will build control arms to fit, and feature large front disc brakes (12.5" diameter). We still have a lot of work to jig up for these, and we will increase the wheel and tire size to work with the bigger front and rear uprights/hubs/brakes.

      Engine Being Built

      We have several swaps going on with stock LS1 drivetrains, but the customer for this Miata wanted something more. His 400 whp minimum power level meant that it would be a pretty hotted up 5.7L LS1, or one with some better head work and internals. We contacted HK Racing Engines in Houston and they came up with a potent little combination based around an LS1 5.7L block we sent them. It will have CNC ported heads, a small duration but high lift hydraulic roller camshaft, and extra beefy internals. The machine work is complete and they are assembling the longblock now. We are using one of two oil pans on this engine...

      The pans above have a much lower front profile than the Camaro LS1 pan that people tend to (cut up and modify) in these Miata swaps, but are nowhere as expansive as custom fabricated oil pans.

      You can see the massive improvement in the front of the sump area, where the steering rack would be. That picture we took is showing showing the factory F-Body LS1 oil pan ghosted over the GM LS1 swap oil pan. Hopefully the Holley or GM swap pan will clear the stock steering rack placement, and more than likely the Holley version will be what we use. We have all three pans here for mock-up test, which we will do as soon as the TKO600 arrives.

      OK, that's all we have for now. We have the transmission nailed down, three oil pan options, new front uprights/hubs/brakes to work off of, the rear differential picked, and a few more things in the works. We still have a LOT of work to do, but this swap is being attacked between other LS1 swap jobs underway at the shop right now (five cars). Just wanted to give a few updates on where we are headed with this Miata swap.

      More soon,
      Last edited by Fair!; 10-01-2012, 06:33 PM.
      Terry Fair -
      2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
      EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


      • #4
        Re: Vorshlag Miata LS1 Alpha Project

        Project Update for January 4, 2014: Wow, over a year without an update? Yikes. While it looks like I have been avoiding this build thread, we have been plenty busy working on this project and many others over the past 14 months. Most of the work we have been doing on this project over the early part of 2013 had to do with upgrades to the shop and building fixtures we needed to delve further down the rabbit hole on the Miata LSx swap. Later in 2013 we also tried a number of oil pans, designed and built a new tubular front crossmember, did all of the geometry calculations then mounted the new front suspension bits, and then we finalized the wheel and tire package. We also worked on a lot of other customer cars in that period, built a few race cars, developed our BMW E36 LS1 swap kit extensively, released our BMW E46 LS1 kit, and a number of suspension development projects in the same time period.

        All pictures in my posts can be clicked for higher rez versions

        We also had a very busy racing schedule in 2013, running 15 events with NASA (among many other groups' track and autocross events) in our TT3 prepped Mustang, shown below. We won 13 of those, got one 2nd and one 3rd, setting 8 track records along the way, while testing all sorts of aero and suspension work (we race to test, and test to race). Another project that kept us busy was developing a new set of NA/NB Miata shocks shown below. These are custom built with Bilstein Motorsports components, using massive 46mm monotube pistons, machined and assembled at Vorshlag, then custom valved by Maxcyspeed & Co. We just finished our final round of track testing last weekend, testing the latest valving package for a dual purpose street/track set-up. I had a blast hooning around in the tester's 2001 Miata below at Eagles Canyon Raceway. These dampers should be in production in Q1-2014 and we will have more information about these in the New Damper Offerings forum thread.

        One thing to note about this post: starting in early 2013, I started making ALL of the pictures in all of my forum posts click-able for larger sizes. With a photographer like Brandon on staff it is a shame to only show the little "small" versions in our posts. So if you see an image you like, click it for a higher resolution version of the same image.

        Before I get going on this update I wanted to shout out to - Just found this forum which looks to be a great resource for V8 Miata swaps, as the name suggests. Our build thread was added there today at this location. I already learned a few things reading build threads there, so if you have plans for any sort of V8 swap in any generation of the MX5 chassis, you should head over there and sign up.

        Shop Upgrades Lead To LSx Swap Progress

        So one of the things we needed to work on this Miata LS1 car was a 4 post lift, which we finally ordered and installed in early 2013. This made it easier to do drivetrain mockups. We quickly realized that we also needed a chassis dolly to make the Miata easier to move around once the subframes were out. So we built that in summer 2013, and soon modified it to fit two other chassis. Now that dolly thing gets used on a daily basis (should have built one of these sooner) to move a car around the shop that has no suspension, crossmembers, or wheels.

        Believe it or not, the lack of the 4 post lift and chassis dolly were big impediments to this Miata LSx project. Since we are still in a somewhat small shop space we couldn't afford to have the Miata stuck on one of our lifts for more than a day or two, which kept us from pulling the front subframe out for more drivetrain mockup (ever try to move a car around without even subframes in it?).

        The Real Engine Swap Work Begins

        Once the lift and chassis dolly were built we rounded up the hardware needed to get the TKO-600 transmission mounted to another LS1 block we have, then put that mockup drivetrain in the car for some testing with the REAL transmission. Before we had eyeballed the TKO in the tunnel but not while attached to the block. This helped us see what the next piece was in the way...

        After we did that round of LS1+TKO mockups we quickly realized that the OEM front crossmember was a HUGE hindrance to this swap, as even heavily modified and hacked up it would be in the way of the engine, oil pan and exhaust headers. We refuse to accept the huge compromises that come with "block header" exhaust headers on any of our swaps, so a new tubular front crossmember was going to be required.

        You can see above some of the structure of the frame fixture that bolts to the body dolly, which Ryan built for the NB Miata. There's actually a lot of steel rectangular tubing you cannot see in this pic. The rolling cart attaches to this frame fixture from underneath the lift. This fixture was built to allow the car to sit at the desired ride height w/o suspension while sitting directly on the lift, with the rectangular tubing setting the chassis height. He then mocked up some 265/35/18 tires at both ends for a quick look. If you shove them in hard enough they almost fit under the fenders, heh.

        Choosing Tires and Suspension To Build Around

        We knew early on that we wanted to upgrade all of the factory (and very weak) 4 x 100mm NA/NB hubs hubs to 5 x 114.3mm RX8/NC hubs. The 4 x 100 hubs are a common failure point up front on Miatas that see any track time, and keeping the rear 4 x 100 hubs would limit the halfshaft strength greatly. Going to 5 x 114.3 bolt pattern opened up a lot more wheel and brake choices as well. Doing this "hub upgrade" is more work than you might think - this meant new uprights and control arms, so the NB suspension pick-up points on the crossmember were no longer sacred... so we might as well ditch it, right? Well we tried to keep the stock crossmember, probably far too long into the swap development. We tried cutting it to make room for this or that (like some of the kits are fond of doing), modifying the pick-up points, but it was getting weaker and more customized.

        Meanwhile we had been mocking up this RX8 front control arms and uprights and even tried an 18x10" wheel and later a wheel and tire. Ryan put in several days of work, and with Jason's help, they did a lot of measurements and calculations and got the front suspension sorted out fairly well. At this point we knew we would be able to re-use the RX8 front spindles, brakes, and control arms. I was worried we would need to fabricate control arms, but it all fit very well with the forged aluminum RX8 arms. Small victory.

        Video we made for the customer, showing the RX8 suspension and 18x10" wheel in action

        In the video linked above we were showing the customer the current location of the wheel and suspension with the big 18x10" wheel, to which we later mounted a 285/30/18 tire. This video shows the front 18x10" wheel turning at ride height, and we later made some adjustments to clear that wheel at full lock, inboard (obviously the fenders will need to be cut and flares added to cover the tire). Our customer has had regular e-mail updates every 2-4 weeks, showing all of what you see here and more. We send these email updates with pictures and videos to all of our long term project customers - basically anyone that has their car in our shop for anything more than just "day work".

        Later a set of 18x8" Mustang wheels (from my 2013 Mustang GT) were installed, shown above left. We noted that these barely fit under the stock fenders, but they didn't have enough positive offset. We might pick up some higher offset RX8 18x8" wheels (above right) and tires, which would sit farther inboard. This could possibly avoid the need for cutting and flares for some folks. Luckily, our Alpha customer is going with the 285mm tire option. Why so much tire? Well the LS1-based 5.7L motor that was built for this car will make 425-450 whp, and in a 2600 pound car with a short wheelbase, that is downright hair raising... we felt that a 285mm tire (Hoosier!) was going to be barely enough to keep it on track when the loud pedal is cranked up to 11.

        One thing that had me a little worried during our wheel and tire mock-up was tire height. Most NA/NB Miatas are using a 23" tall tire, which is SUPER SHORT and only come in sizes out to about 215mm or the occasional 225mm. We went away from the typical 14-15" wheels to clear larger RX8 front "sport" rotors, which at over 324mm diameter are too big to fit inside a 15" or 16" wheel. Then tire width choices started to come into the picture... there just wasn't anything wide enough in 14, 15, 16" or even 17" diameters (the last two diameters tend to top out at a 255mm tire width for most brands), so we jumped straight to 18" - which currently has the most options for wider tires in both street and race compounds, covering widths including 275, 285, 295, 315 and beyond. We're building our TT3 Mustang around a 345/45/18 in the 2014 season, for instance. You can almost never have too much tire width on a race car...

        Turns out there wasn't any tire anywhere near 23" tall once you left the skinny options in the 14-15" wheels, so we chose the shortest tire that is also wide that we knew of - the 285/30/18. This tire is normally the magic solution to "going wide" on track or autocross cars, and we've used this 24.9" tall monster tire on lots of BMWs (see above right, which has a bit more tire height room), EVOs, Subarus, and more. They even are used on RX8s and NC MX5s, but those cars have a lot more "wheelhouse" room than the NA/NB chassis. So we will likely cut the front upper frame horns for more clearance at full bump travel (then add back more structure with welded steel tubing). The above left picture shows the suspension at about 1.5" of bump, which isn't enough. Oh well, using a 2" taller than stock tire causes some problems we will have to overcome, but they aren't anything we haven't tackled before on other chassis.

        New Crossmember Development

        Once the tire was chosen and the front hubs and suspension components were tested and mocked up, we were ready to start burning in the pick-up points onto some sort of crossmember - either the stock piece or a custom design. At this point it was obvious that the OEM front crossmember was the next big stumbling block and it had to come out, once and for all. We just couldn't save it (it was already cut-up so much to clear the engine that it would need major reconstructive surgery), we didn't need it (we were changing all of the suspension pick-up points), and it was just in the way. So first the Vorshlag crew fabricated a crossbar that held the front of the engine from the top, which rested on a part of the upper chassis that wasn't going anywhere. Then they made a similar and also temporary rear transmission crossmember that was bolted in place, so the driveline position and angles were set. In the step above you can see the OEM crossmember out of the car for a bit, but now it was time to be fully replaced.

        Now that the drivetrain was where it needed to be we connected the dots to build our new front crossmember. Using lengths of 1.75" diameter x .120" wall DOM steel tubing, Ryan measured then mandrel bent the new fore-aft frame members. These tubes were spaced inboard enough to maximize exhaust header space as well as set the final lateral and vertical locations for the RX8 lower control arms, which had geometry already determined above. These main fore-aft tubes bolt at both ends of the engine bay, onto factory chassis mounting locations that have substantial strength. Unlike the stock front crossmember, which mounts at the rear of the engine bay and at the midpoint (where the suspension parts mount), the new tubular design would mount at those points plus forward at the front tow hook tie down mounting plates. Our crossmember should make for a more rigid chassis when it is completed, with less cowl shake and more stable suspension mounting.

        continued below
        Last edited by Fair!; 01-06-2014, 04:01 PM.
        Terry Fair -
        2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
        EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


        • #5
          Re: Vorshlag Miata LS1 Alpha Project

          continued from above

          You can see Ryan welding the front mounting position of the crossmember tubing at the tow hook mounting plate, which is a beefy piece of plate steel bolted to the front of the chassis with plenty of bolts on both sides. With these two main crossmember pieces in place several things were then test fit. First, 3 different LSx oil pan designs were fitted to see which provided the best clearance to the lateral tubing member that was still needed as well as clearance to the NB Miata steering rack.

          Each oil pan design had some advantages and disadvantages, with the total depth of the pan's sump driving how low we could get the drivetrain in the chassis, and the front section of the pan limiting where the steering rack would end up. In the end we chose the oil pan from the 1998-2002 Camaro, which is commonly available from the aftermarket. The Holley swap pan and the GM Muscle Car swap pan both had issues that could not be overcome. Luckily we didn't have to settle on a fabricated oil pan (these always seem to leak), the GTO double-hump pan (we have used that one and do not like it) or another cut-up OEM pan. There are good baffle/trap door kits made for the Camaro pan (Improved Racing's unit is preferred) and we have a lot of miles on track with this oil pan and baffle in BMW E36 LS1 swaps.

          This is our prototype front NA/NB engine swap crossmember - additional gusset plates and tubing will be added before final welding

          The final LSx oil pan we picked ('98-02 Camaro) is shown above, after the lateral tubing member was tack welded in place. Two vertical tubing members were also added, welded mid-way from front-to-rear and landing on some plate steel that bolts to the stock crossmember front mounting holes (which doubles as the upper control arm inboard mounting point). This makes for a completely bolt-in tubular crossmember, with extra mounting bolts/locations, once we get it into production (we will replace the OEM tow hook tie-down plates with a new, Laser Cut plate version). It also has a LOT more room for the engine and exhaust headers, so we can develop real exhaust headers - which can make upwards of a 50 horsepower difference on an LS1 V8 over the block-hugger super shorty headers some kits are stuck with. And this crossmember could work with a LOT of other engines as well.

          We weren't going for the "lightest crossmember on the market" here, as I cannot count how many lightweight tubular crossmembers I have seen bend or fail. No, we wanted the STRONGEST possible fabrication we could come up with. The .120" wall thickness on the 1-3/4" DOM tubing we used might be overkill, and we could step that down to .095" wall on a later prototype piece (we will surely make some tweaks to this design before it is ready for mass production), but when it is completed we will weigh this first tubular unit vs the stock OEM stamped sheet steel fabrication and see where everything shakes out. A crossmember is not somewhere you want to skimp on.

          Throttle Body Clearance, Air Cleaner Routing, Possible Hood Ducting?

          Of course before the oil pan and engine heights were finalized we tested with an intake manifold and throttle body on the mock-up LS1 engine, then tested with the stock hood in place. We had plenty of room up top, but realized that due to the short length of the Miata engine bay the intake inlet tube would have to go "over the top" of the radiator support (yes, this means we have to lose the factory hood latch). We've done this type of air inlet re-routing before, like on our TT3 Mustang shown below.

          This was one of the many custom tweaks we had to do on that car to make room for a deeply ducted hood, which vented the back of the radiator and made the front splitter much more effective. This had an accidental side effect of offering a lot more cooling capacity (and front downforce) to that car, so we might do something similar on this LS1 Miata, and of course use a bigger radiator at the same time.

          Ducting the Mustang's hood made the front splitter we built MUCH more effective, both for cooling and front downforce

          There are plenty of Corvette style air filter housings we can choose from, which was the air filter we ended up with on our TT3 Mustang. So after the intake manifold was fitted the Miata's engine height was locked down, and the driveline down angles were set at the transmission. Next up it was time to burn in the RX8 suspension mounting points to the new crossmember...

          Final Welding of Suspension, Brakes Added

          Our fabricators Ryan and Olof made some steel mounting plate sections on the bench that were then fitted to the tubing and tack welded in place on the crossmember. Then the suspension was mounted up, the wheels were added, and everything was set to ride height... to re-check camber, caster, toe, and then camber and caster change with suspension travel. Obviously you don't want caster change with suspension travel, so that was dialed out.

          It doesn't look like much but dozens of hours were burned getting these mounting points welded in, measured, moved, and tweaked. Mazda-sourced eccentric bolts are used at the same suspension mounting locations as the RX8, to be able to adjust camber and caster. And while some of you suspension savvy readers might point out that the upper arm's mounts aren't perfect (we wish they were about an inch higher), they are as perfect as we could make without cutting the frame out of the NB chassis or going to custom control arms. There's a lot to be said for re-using OEM forged aluminum arms, which can make for easier service and maintenance down the road. We checked the dynamic camber change and it turned out to be pretty reasonable, too. Remember: Vorshlag specializes in suspension development, so this was an area we really made sure to get right. And we could see something in track testing that might make for future changes before this kit goes into production, too.

          Seeing the old front suspension and brakes on the shop floor next to the new stuff is quite a difference. We're upgrading from a 254 x 20mm vented front Miata front rotor to a 323 x 24mm RX8 Sport front rotor. Going with RX8 hubs gives us a lot of Big Brake upgrade kits to choose from down the road, if needed. This customer wants a car he can track, autocross and street drive across country - and it will have 450+ hp and sport 285mm tires, so it will have some extraordinary braking requirements for an NB Miata.

          These RX8 calipers and rotors are all Centric premium units that we sourced new, so it should make for a good starting point for track and street testing. We will also add front brake ducting, at a minimum, before it sees any track testing. That makes a huge difference on most road course cars we deal with, and it doesn't cost a lot nor does it have any downsides for street driving.

          What's Next?

          With the front crossmember, brakes and suspension nailed down and in prototype form it is time to move to the rear suspension. The front bits had so many variables that all cross over each other, but without steering involved we're hoping the rear will go more smoothly and quickly. As you can imagine the customer is getting anxious to drive his car, and wants to run events this year, so we've got to get crackin!

          None of the OEM rear control arms, brakes, and hubs will be re-used. Again, we felt that the small-ish rear hub's inner spine size would limit the power capability of any halfshaft that could be built for these cars. I've seen fellow racers shred axle after axle in LS1 equipped Miatas, and I don't want to get stuck with those limitations on our swap. So this means it all has to come out and we get to start over. Yay.

          The diff housing we are using is of course the 31 spline Ford 8.8" aluminum IRS casing that was used on the 1999-2004 Mustang Cobra. This was also the same housing used in Lincoln MarK VIIIs, and steel versions were used in the Thunderbird and Explorer chassis. The new S550 Mustang chassis looks to have the aluminum version as well (we should have one of these Mustang's soon for chassis/suspension development in late 2014 and a full season of racing in 2015). All this means is these diff housings are both common and affordable, not to mention strong as an ox. Aftermarket choices abound for gearing and internal differential options, too. We also have the rear uprights chosen, which are a commonly used unit for Cobra kit cars.

          The real motor needs to be installed, of course, along with the accessories/brackets and clutch system

          For now we will use the OEM rear subframe to mount things to, at least during mock-up. Once these uprights and the diff housing are mounted and set at the right heights and locations, we will fabricate upper and lower control arms, check the suspension geometries, then move to the halfshafts. This will entail a lot of fiddly work, measuring and calculations, of course, but compared to the front bits (which had to have an engine, transmission, suspension and crossmember all mate up) it should be a little less work.

          Until next time, thanks for reading.
          Terry Fair -
          2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
          EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


          • #6
            Re: Vorshlag Miata LS1 Alpha Project

            Project Update for June 25th, 2014: Long time no post on this project once again, but with some recent changes and progress we have regained some lost momentum and we are pushing to get this prototype LS1 NB Miata on the road by this Fall. After a spurt of work in January and a little more in April, some real time was spent on this project in May. Let's get caught up.

            The biggest progress of late was a new milestone that was started and finished since the last post - the rear subframe and suspension was constructed. Right now the car still sits on 18x10" wheels and 285/30/18 tires at all 4 corners, with the new RX8 front suspension tacked up as well (see above). The front obviously needs more negative camber (and more adjustment range), which we're working on next.

            Ryan, that started fabrication on this project has left us (left) but our new fabricator, also named Ryan, is on the case (right)

            We had a few delays on this project in the months since the last post, due to a few unforeseen changes here at Vorshlag. For one, our lead fabricator Ryan B (above left) left us after almost 3 years of great work to pursue his college degree full time. He was working here part time for the past year and whenever we had to steal him for major fab work at our shop he didn't get to focus on the Miata swap often or for long. After he left we searched for over a month and found another great fabricator to join us, Ryan H (above right), who joins us with lots of race preparation and fabrication experience from a Daytona Prototype team and other previous race shops.

            As soon as Ryan H started here we buried him in fabrication work on a customer's V8 swapped race car, then he spent 100 hours working on the Pikes Peak Subaru above. Once those pressing deadlines were passed he got to spend about a week and a half working on the LS1 Miata and a lot of progress happened, back in late May.

            Custom Rear Subframe Construction

            We weren't sure which way the rear subframe and suspension would go until we just dove in and started mocking up parts. We knew the factory rear hubs were going away, as we wanted to fix the problems we've seen in our V8 swaps to this chassis when we made ours - namely, busted halfshafts out back and fragile hub bearings at both ends.

            There wasn't much to start with when Ryan got to the back of this 1999 Miata. We had looked at using part of the old factory rear subframe structure and cutting it up to fit the Ford 8.8" aluminum center section. The problem was the new diff was so large that most of the top of the old subframe had to be removed and very little structure would be left.

            The stock differential housing, rear subframe and rear control arms were removed so we could mock-up the new parts we wanted to add. The rear hubs/uprights were ordered then we mocked up the Ford 8.8" IRS diff housing...

            There was no way that 75 pound aluminum diff housing could fit without hacking the stock rear subframe beyond recognition, so it was set aside intact and fabrication of an all new rear subframe was started. The Ford diff housing was mocked up using some straight tubing passing through the new rear hubs and uprights we chose for this new set-up. These were chosen for their "high torque capacity" sizes on the hub bearings and the splined size for the halfshafts. Nothing that uses the OEM rear NA/NB Miata hubs or input spline can live much beyond about 250 ft-lbs of torque for very long, at least not with grippy R-compound rubber. The LSx motor that has been built for this Alpha car will make more than double that (450 ft-lbs+)

            The uprights (below) we used are aluminum, very strong and work with the 5 x 114.3 mm bolt circle hubs shown above. This rear hub will work with the same wheel bolt pattern we're using up front, which we borrowed from the best OEM Mazda front bits. The entire front suspension is based on the beefier RX8 hubs, uprights, brakes and forged aluminum upper and lower control arms.

            We also switched to a different rear cover for the Ford 8.8" IRS housing, which is shown above, deciding not to use the 2004 Mustang Cobra cover. This dual ear "winged" mounting style cover used is similar to the style that comes on the BMW E36 chassis and somewhat like the C4 Corvette Dana 36/44 housing - both cars we have worked with and raced hard for many years without issue. This style cover is easier to work on and mount to than the "clamped center mount" '99-04 Mustang Cobra rear cover used in our earlier mock-ups. This newer cover also has both fill and drain plugs on the cover, for use with a possible differential fluid cooler (common for heavy road course use).

            continued below
            Last edited by Fair!; 06-26-2014, 11:39 AM.
            Terry Fair -
            2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
            EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


            • #7
              Re: Vorshlag Miata LS1 Alpha Project

              continued from above

              The goal was to be able to use stronger OEM based and commonly available hubs, brake parts & other consumables (not one-off fabricated or race-only parts), and have the same wheel bolt circle front and back. This way if you blow through your brakes or wear out hubs at a track event, you can run to a local parts store to get replacements fast.

              Ryan jumped into the new rear suspension and subframe design with both feet and spent a full day making measurements (see above) and checking suspension geometry using 3D node software, to check camber change through suspension movement. Using the short upper and long lower arms and moving the pick-up points in computer space, then checking the camber change under movement. The final pick-up points and geometry chosen looked great and the dynamic camber change was well within normal parameters.

              This is major fabrication work coupled with suspension design, and not something usually done by just "anyone that can weld". Luckily it wasn't too challenging for our crew - we are primarily a suspension shop and all of us are racers - and the new subframe and suspension design was knocked in a little over 70 logged hours.

              The start of the upper structure of the rear subframe is shown above and left. The beefy new subframe unit will bolt to the 6 factory mounting studs in the rear of the chassis, without any cutting or welding. Once it is finish welded I will share the final weights vs the OEM bits, but it should add little to no weight over the stock rear assembly. The picture above right shows some of the tubular steel custom rear lower control arms going together. These are adjustable and feature polyurethane mounting bushings for some cushion but nowhere near the slop of a rubber mount. This should be suitable for a dual-purpose street/track car, but we could also make these arms with spherical ends for track-only set-ups.

              These hub-mounted stands worked well during geometry checks and suspension mock-up and fabrication. Lots of fixtures and welding jigs were built to be able to make the parts uniformly and mirror imaged from side to side.

              Here you can see the aluminum 8.8" diff housing starting to be fitted to the tubular steel rear subframe structure. Polyurethane (red) bushings were used in the front and rear mounting locations for this housing.

              The front diff mounting brackets are shown below at right. There is a gusset to add on each side but otherwise that section of the subframe is finished.

              You can see the rear chassis studs and bolt holes that the new subframe mounts to, below. There are some scalloped areas that will be added for more bolt/nut clearance, and small tubular gussets here and there, but this is the final layout we're going with.

              There are a few gussets to be added, then final welding can be done and the subframe removed for powder coating.

              What's Next?

              We've already had started on the front subframe and it was mostly done. Now we are tweaking the front geometry to allow for more camber and caster adjustment, using the RX8 eccentric bolts/washers and OEM style "cages" around these bits. Once the front subframe is completed we will design and build the LSx V8 motor mounts (takes about a day and a half). After that the prototype header fabrication and a driveshaft can be built. We have an aggressive schedule to finish this car this year, so stay tuned for more updates. We will be making production runs of both subframes, for use with LSx V8 swaps as well as racers with boosted Mazda engines that want the reliability and durability of the higher strength hubs, halfshafts and diff housing we're using.

              Last edited by Fair!; 06-25-2014, 04:39 PM.
              Terry Fair -
              2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
              EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


              • #8
                Re: Vorshlag Miata LS1 Alpha Project

                Project Update for December 17th, 2014: We've been busy on the Miata over the past few months but I've just been too busy to get caught up on the forum updates. We just finished construction and a big shop move for Vorshlag, doubling our available space, which ate up a lot of my time. This move has made for some extra room to work on projects like this, to add some new fabrication equipment, and just this past week for two CNC machines (lathe and mill) to finally make our machined Vorshlag products 100% in-house.

                Right after the move in November a majority of Vorshlag folks also went to SEMA and then we were competing in OUSCI (Optima Street Car shootout) in our TT3 Mustang. Then Jason went to the 2014 PRI show and took 100 pics of cool new parts. Ryan stuck around at our new shop in Plano, Texas, and worked on the Alpha Miata V8 and made some really good progress. Then he found some more days in late November and early December as well. Anyway, we have all been slammed, but big progress has been made on the Alpha Miata.

                The 2014 SEMA show and the OUSCI competition were fun but ate up a lot of time I where could have been updating various build threads

                Front Suspension Follies!

                Last time we updated this build thread, Ryan had finished re-checking the geometry on the rear bits, tweaking the rear subframe and making new rear control arms. That was back in June. In August he was freed up a bit and finish-welded the custom rear rear control arms. They are ready for shock mounts, cross bracing and custom half shafts at that point, but the rear subframe still needed to be final welded. He wanted to tackle the front before "locking down the design" (track width, ride height, etc) out back.

                Now we move ahead to some time he had in August, when he moved to the front, to re-run the 3D geometry on the RX8 spindles/arms that we already had mocked up and tacked in place to the custom tubular front subframe. Well... while it looked fine to the naked eye, once the wheel was at the proper ride height (now visible with the RX8 hubs mounted to the new hub-stands, shown above) the geometry was less than ideal. Once the pivot points were input into suspension analysis software it was obvious that anti-dive and bump steer were terrible. Still, I wasn't giving up on keeping the suspension/brakes "all Mazda" up front, so I had him stick with the RX8 bits a little longer and try to move the pick-up points to try to dial some of this out.

                Ryan cut off the previous pick-up points and made new ones, then rolled the mounting points as far as he could within the constraints of the stock front Miata tub and the RX8 arms. After sourcing some factory Mazda RX8 eccentric bolts and making the new control arm mounts that mimicked the factory subframe mounting points, it looked great and had the adjustments we needed, but the geometry still wasn't getting much better. He did some 3D measurements, saw some room to improve, then yanked the subframe and started over - making an all new front subframe section, from scratch, to gain some room for our the RX8 suspension at the lowered ride height and to fit with the big tires we had in mind. Two steps forward, one step back - that's how it works sometimes. The second, new subframe was tack welded together and had several improvements, and we would end up sticking with that through the next suspension iteration.

                After he re-installed the RX8 bits it still wasn't good enough, so our engineer Jason and I asked Ryan to just fabricate new control arms to use with the RX8 uprights and hubs, but after an exhausting search the OEM style ball joints for the RX8 (very funky taper and size - nothing like anything supported by the aftermarket) were not available separately, so this was a dead end. Bah! I finally pulled the plug on the RX8 spindles and pretty aluminum control arms. We had already acquired brand new RX8 brake parts, too. Oh well, some ideas just don't pan out. Lots of fabrication hours were wasted based on my notion of using OEM RX8 spindles, brakes and front control arms.

                After this latest wild goose chase we had Ryan stop working on the car for a few weeks while engineer Jason and I regrouped, to look for other front suspension and spindle solutions we could utilize. After this debacle we realized that swapping in another set of control arms wasn't going to work inside the narrow confines of the Miata without several miracles, so instead we focused our search on a good OEM uprights that was made for a double-A Arm suspension. The result was we found something much better than the RX8 bits - lighter, forged aluminum, even more common to find, with tons of aftermarket support, beefy front hubs, and dozens of OEM and aftermarket big brake options. So, what did we use?

                When In Doubt, Just Use More Corvette Parts

                Corvette C5 spindles were the chosen upright this time (C6 are virtually interchangeable, too) and the first one we purchased looked great - and proved to be significantly lighter, too. And honestly we don't care where the parts come from, if it meets the criteria for use on a hybrid build like this: use the best parts available, that can be purchased at the best price, with good aftermarket support, easily procured consumables, and the best materials/strength/design.

                The C5 aluminum upright was 5.6 pounds (13.96 pounds, with hub and ball joint installed - and the unit bearing hub is BEEFY!) compared to the 15.5 pound RX8 steel upright and hub. The nice thing is that the front and rear spindles on a C5 (and C6) are interchangeable (RF and LF are the same, LF and RR as well), which doubles your chances of picking them up second hand. Once we had one of these forged C5 spindles on hand, new ball joints were ordered next (we first made sure first that they were available separately!) and Ryan started making a whole new set of upper and lower control arms.

                These would be tubular, the right lengths, and after some analysis, end up with better geometry, and have more range of alignment adjustment than the "eccentric" bolts of the RX8 arms. We could now adjust camber and caster through a larger range and achieve proper geometry at the ride height we wanted without cutting up the Miata tub. The lower arms would house the C5 ball joints and the upper arms would accept the matching C5 upper. The ends we chose were firm polyurethane bushings and the lengths were to be adjustable. A lot of pieces were ordered, many more were custom machined, and a lot of hours were spent calculating, fabricating and measuring.

                Making this car as a one-off build would have been SO much easier - we would have just notched out part of the frame and made the RX8's control arms pick-up points fit in space where they would work for the geometry. But we have been going to great lengths to keep this subframe and suspension a reproducible kit, and to keep it a purely bolt-on set of parts, which meant not chopping a chunk out of the front frame section to move the upper control arms upwards. In the end we found that the C5 spindles, with the OEM ball joints aimed as they are, allows for the geometry we needed within these MX5 chassis constraints, using these custom control arms. BOOM!

                Steering Rack Placement + New Steering Shaft

                Once the new front control arms were fabricated and tacked welded, then geometries rechecked (both manually/visually and in software), it was at a good stopping point. Ryan then began to tackle the front steering rack mounting.

                The NB Miata steering rack was placed in the ideal location for the slightly altered wheelbase and new front Corvette spindles, keeping in mind the necessary oil pan clearance. We have a half dozen different LSx oil pans around here to test with, so we worked with those to find the right combination to clear the steering rack without adding bumpsteer. The final rack mounts were fabricated and tacked to the crossmember.

                This new rack location (and the small wheelbase change) would mean we would need new, slightly longer intermediate steering shaft assembly in the engine bay. Luckily we're used to making those for all of our BMW LSx swaps, so this is another bolt-on solution. What you see above is a mock-up - with one of the two aftermarket steering U-joints installed with a piece of 3/4" Double D shaft, to check lengths. The final solution will be a proper 2-piece collapsible steering shaft assembly like our many Vorshlag BMW steering shaft assemblies (see below). We make these to improve header clearance for V8 swaps on various BMWs, improve the heat resistance of the U-joints (the OEM steering shafts on LHD cars with inline engines are not meant to see exhaust heat) as well as to remove nasty rubber "rag joints" (steering shaft isolators) in the shaft, for better steering feel. We even sell a lot of these steering shafts to BMW racers who keep the BMW engine, just for the improved feel.

                Olof took a fresh NB steering rack core and converted it to a de-powered rack (we do this work on NA/NB Miatas often), welding up the bits necessary. We will use no power steering in this car initially, then switch to an electric assist solution if it is deemed necessary.

                Front Drive Accessories

                Running no power steering pump will create some headaches but also solve some potential problems. Hydraulic fluid power steering assist is always a hassle in any car; the system can make for a huge mess when it leaks, and requires an engine-driven hydraulic pump, reservoir, cooler, and high end hoses on a tracked car. This system is the number one cause of on-track fluid leaks and underhood fires, so taking hydraulic power assist out of the equation is fast becoming part of our track-worthy upgrade list for all cars. Many OEM cars these days are coming with "EPAS" systems from the factory, which makes for aftermarket electric steering assist solutions that are numerous and proven - since many are just re-purposed OEM systems. This means they can even be cost effective. And lighter. And no longer based on flammable, high pressure fluid that robs power from the engine to pressurize. Win!

                A recent LS1 mock-up (October) with a set of accessories that does NOT have a power steering pump

                And while it might seem simple to run any old LSx engine without a power steering pump, it was actually pretty tricky. This particular accessory drive arrangement was figured out on our FR-S LS1 Alpha swap, with some help from the itnernets plus some custom machined bits made here at Vorshlag. That car has an electric assist in the column, so it did not need the pump.

                We couldn't find a factory set of LS series engine accessories without the P/S pump, so we went with a proven version that had GOOD front clearance (shown above on the FR-S LS1) and narrow packaging, then the normal main serpentine belt routing was changed to bypass the missing power steering pulley. To accomplish this an extra idler pulley was added, and things were moved around to give proper belt wrap on each pulley - especially the balancer (SFI unit secured with a massive 12-point ARP bolt). We took some measurements then borrowed this set of accessories from the FR-S and test fit onto the built Miata LS1 motor, it fit great (see images above), so we're replicating that set-up now for the Miata. It took a few iterations but we finally got the right length belt (these were the "almosts")

                Motor Mounts and Transmission Crossmember Design - With A New Twist

                Once the newly modified, de-powered NB steering rack was mounted to the subframe with some beefy, fabricated brackets (see above) we wanted to then lock down the designs for the motor mounts and transmission crossmember. But now that the tubular subframe was built and the rack was tweaked to fit the C5 spindles, Ryan saw some extra room and tried something I didn't expect... he put a Tremec T56 6-speed behind the LSx mock-up motor and stuck it back in the car. Again. Yes, after all the testing and trouble we went through to make the Tremec TKO600 5-speed fit, he went and stuck a T56 in there.

                I had told Ryan when he came on board at Vorshlag that the T56 would never fit this car, both because we tried this transmission before (with the OEM crossmember, and then a cut up OEM crossmember) as well as the fact that all of the other LS1 swap kits for the Miata require cutting the tunnel to make the T56 fit this car. "Waste of time."

                Thankfully, I was wrong this time. Now the bigger, stronger T56 did fit - and fit with room to spare! Apparently in our previous T56 testing the Miata's OEM front crossmember was the limiting factor. That big, bulky plate steel structure moved the drivetrain up significantly, which is why the T56 never fits the Miata tunnel on most swaps without cutting the tunnel to make room.

                Left: The initial LS1/T56 mockups were a bust with the OEM crossmember in place. Right: With the tubular crossmember we have lots more room

                This is because the LSx/T56 drivetrain is being moved upwards inches from where we have our drivetrain. With our latest (version 2.0) bolt-in tubular front crossmember, the engine sits lower and so does the transmission, so now it fits. It still has ample ground clearance to the oil pan, which is tucked up just above the bottom of the crossmember and bottom of the Miata tub. The T56 shifter location lines up perfectly with the factory Miata shifter hole. Moving this drivetrain down worked another miracle, and it lowers the CG, too. Win-win.

                continued below
                Last edited by Fair!; 12-19-2014, 07:41 PM.
                Terry Fair -
                2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


                • #9
                  Re: Vorshlag Miata LS1 Alpha Project

                  continued from above

                  That big transmission change threw me for a loop, but so be it! A brand new Tremec T56 Magnum costs more than the TKO600 new, but not by much, and its a more popular trans so we called up our Tremec supplier and we had a brand new close-ratio T56 Magnum on hand the next day.

                  Tremec T56 Magnum - close ratio version - rated to 700 ft-lbs of torque!

                  If you know anyone that needs a GM-style TKO600, brand new, we will have it listed for sale here until it is gone, for less than they sell for now. We still have to get the correct flywheel, clutch and pressure plate for the T56, but those bits are already on order and should be here next week. During all of the transmission testing our crew removed the mock-up LS1 motor for the last time and installed the built 5.7L LS1 that the Alpha customer purchased for this build, made by the masters at HK Racing Engines.

                  Left: The built LS1 with borrowed accessories and LS3 intake in the Miata: Right: LS1 with same accessories and balancer in FR-S

                  This motor has a built bottom end, CNC ported heads, big lumpy cam, proper valvetrain, and all sorts of race parts inside. Should make in the neighborhood of 450 whp on pump gas. Ryan chose the 98-02 Camaro oil pan during his testing, so we ordered an Improved Racing oil pan baffle kit to fit this pan and that's in place. We won't build a track-duty car with an LSx without an oil pan baffle from Improved Racing. After talking to those guys at SEMA they realized how many of these LSx baffle kits we've used over the years and made us a dealer, so we'll add these to our website shortly.

                  Left: The accessory arrangement we used has ample room for an A/C compressor, as shown. Right: Improved Racing oil pan baffle will be used

                  Once the oil pan and accessories were locked down, then Ryan could start to build the motor mounts (see below left), which he knocked out in about a day. These look like many of the designs we have used on BMW E36, BMW E46, BMW E30 and the FR-S/BRZ swaps done here at Vorshlag.

                  A production set of similar mounts for our BMW E46 LS1 swap, black gloss powder coated. We make these in-house with CNC laser cut pieces

                  When you have a robust, proven design that has been made 100s of times, you use it. These make for a strong, reliable, low vibration mount that has no movement when torque is applied. These then bolt to a gusseted, plate structure welded to the tubular subframe (see below right).

                  To make the transmission crossmember required a bit of extra work, at least on this Alpha build. Like on the FR-S swap (after we made room for the longer T56 Magnum XL we used on that car) this NB Miata chassis has no transmission crossmember mounting on the chassis. The front mounting points of the "PPF" on the NA/NB Miata is the transmission mount (which is similar to Corvettes from C4-C7), but we ditched that since the T56 Magnum had no provisions for mounting this ladder frame to the back of the tail housing. Modifying the transmission to fit the factory PPF would be a nightmare to reproduce in kit form.

                  Left: The heavy stock dash was removed to make room to pull the carpet. Center: Inner plate brackets. Right: Shifter lines up very closely

                  To make room for the next step, the dash was removed. Why? Two reasons. First, we wanted to see how much the entire NB dash structure weighed. 49 pounds is the answer. Second, to remove the OEM carpet intact the dash has to come out. We needed to add some backing plates inside the tunnel under the carpet, to hold the transmission crossmember brackets inside the tunnel, so the carpet was pulled. For the kit version we'll have templates for where to drill holes and you can slit the carpet to slide the plates under the carpet without removing all of this, hopefully. Mazda just makes it extra hard to remove the carpet on these cars - dash and everything is in the way.

                  Left: Outer tunnel reinforcement plates. Right: The transmission crossmember bolts to inner tunnel reinforcement plate mounts

                  As we did on the FR-S swap, mounting plates were bolted to the chassis on both sides of the transmission tunnel. These can stay in place, and the crossmember then bolts to the inner mounting bracket plates. This sandwich of plates (one set inside the tunnel and the matching plates inside the cabin) makes for a strong mounting arrangement which we've used in the past. The removable crossmember bolts to those inboard mounting plates and this, in turn, is what the transmission bolts to.

                  The raw steel crossmember shown above is semi-finished; we will add more gussets when we final weld the assembly. It has lower reliefs that could clear up to two 4" diameter exhaust tubes, but we will build this car with a dual 3" exhaust - which still has massive flow potential. We used our proven red polyurethane transmission mount bushing from other T56 swaps in this set-up, but we also make a machined Nylon busing for a pure race car.

                  Subframe Final Welding - Times Two

                  After the drivetrain mounting was designed and built, the motor was once again removed and the tack welded front subframe came out for final welding. This step took two solid days, as welding fixtures had to be built and then additional gussets had to be made and welded in place as Ryan went through the tacked joints and TIG welded everything. The end result is shown below, and is a very strong work of art. Production fixtures would key all sorts of CNC laser cut pieces into place, and that is much more elaborate, but we will make those when we blow the car apart for the last time.

                  After the front subframe was finish welded they put it back into the chassis (raw), installed the steering rack, mocked up the steering shaft with the new forged U-joints, and shop manager Brad shot the pics below. We will keep the fabricated bits in raw steel until after the initial road & track testing is completed, so if we need to make any changes we're not grinding a powder coated finish off to add something.

                  Last week Ryan removed the rear subframe assembly from the car (at that point still just tack welded) and got to work finish welding that. As with the front subframe, he added gusset plates here and there, boxed in a lot of structures, and TIG seam welded everything as he went. He also built several welding fixtures to keep everything straight and true during welding.

                  He's finished with the bulk of the work on the rear subframe now (we will still add a reinforcing plate or "X" tubular structure to the bottom - he adding mounting tabs for this) and the project is just awaiting a big shipment of parts before we jump to the next step. We have put a few teaser pics out there during these various fabrication steps and people have really liked what they have seen, and we even have people already in line for these kits. So yes, we're going to have to produce all of this in kit form. It might end up a bit pricier than other kits out there, so we may make them in pretty low volumes, but this will not be our last V8 Miata.... no no no.

                  What's not to like? The weight will still be at or under 2500 pounds, with a 6-speed capable of taking 700 ft-lbs of torque, the motor we have for this will make 450+ whp and you can make 600 whp on pump gas with a little bit more spent. We're upgrading ALL of the weak points of NB Miatas and previous V8 swaps, with the move to C5 spindles/wheel bearings and the rear hubs we've used. The Ford 8.8" aluminum IRS center section is super stout and has lots of LSD options. Its going to be a potent little beast.

                  So that's what we have been up to on this Alpha Miata V8 over the past 5 months: we tweaked and measured the RX8 bits, made a brand new front crossmember, chucked the RX8 bits, made another all new front suspension with Corvette spindles and brakes, made a T56 possible without cutting the tunnel up, finish welded the tubular subframe assemblies on both ends, finish welded the custom suspension bits, and everything so far is a bolt-in (except the two notched sections at the back of the engine bay). Should be kit-able. Should be fun.

                  What's Next?

                  The flywheel, clutch and bellhousing are ordered and should be here in the next week or two. Same goes for the final front engine accessories and brackets - the borrowed set shown is already back on the FR-S. The next big step is fabricating the full length stainless headers.

                  Left: Vorshlag built full length prototype headers for Scion FR-S LSx. Right: Production CNC bent stainless headers for Vorshlag BMW E46 LSx

                  We finished the custom prototype set of full length headers about 6-8 weeks ago on the FR-S and last week we tested the 2nd production iteration, and its almost perfect. Making the prototype headers, bend by bend, is a tedious process. We use a few tricks (the plastic snap-together bends help mockup) but it still takes more than 40 hours to make the first set. With materials and our shop rate that would be over $5000, which is crazy - but that's what one-off set of stainless full length headers cost for a V8. Of course we will we have the prototypes transferred digitally in 3D, then have the tubes CNC bent, and production headers made in batches of about 10 sets - which pulls the retail price for these swap headers down around $1700.

                  Seems like a lot until you consider that these are very low volume production parts made for an engine swap, unlike typical high volume "store bought" headers. These are also made from real 304 stainless, have proper merge collectors and V-bands, and are 100% made in the USA. The full length 1.75" primary design tends to add about 40-50 whp over stock manifolds or block-hugger style headers. And proper full length exhaust headers like these adds "guilt free power" over manifolds or shorties, with no downsides. These will add power to low, middle and upper RPM ranges alike. In our experience, the myth about "long tube headers killing torque" is utter nonsense. No, they won't be Tri-Y designs, nor will the primaries be perfectly equal in length, they will be the best headers that can fit the confines of this chassis/subframe/engine, with the least number of restrictive bends - that works better than "equal length" headers with tons of unnecessary, tortured bends.

                  We still need to make the driveshaft and halfshafts, then pick the final wheel sizes and get those built to order on the car. We will re-drill the rear hubs to match the fronts (rear is Ford 5-lug, front is GM 5-lug; our new CNC mill will make quick work of that). And we still have to do the cooling, and plumbing, and wiring, and fuel. It seems daunting but honestly, the hardest parts of this swap are behind us - the all new subframes and custom suspension arms were the BIG development hurdles on this project. You will now see a lot of what we learned on previous BMW V8 swaps and the current FR-S V8 swap on the rest of Miata, and those V8 swap experiences over the past 12 years will help us get this one to the finish line. The Miata swap is much more extensive (since it needed hubs, suspension, diff, and entire subframes) than others in the past we have built, which has made this one take us a bit longer than we'd like - but doing it right takes time.

                  A lot of folks keep asking us - when will this be done? And my answer is - its done when its done. The owner of this car has been extremely patient, but when you are an Alpha customer for a new swap like this, the shop ends up eating $20-30K+ in labor for the first build (hundreds of hours of research, testing, trial/error, fixturing, and hand built fabrications), so that's what their patience nets them.

                  Once the wheels and tires are picked and installed we can make some flares to cover the (likely) 285/30/18s at all four corners. We just went through this work on my TT3 prepped 2011 Mustang and Ryan built some beautiful metal fender flares to cover 335mm front tires (which go with the 345mm tires and rear flares the car already had). We can do the same work on the Miata, no problem. The owner of the car, Jason, is picking up a fiberglass front end that should work better with the wider track width and we'll tie the flares into that.

                  And YES, one more time, we plan on making a kit for all of this - tubular front subframe, tubular rear subframe for 8.8" Ford IRS, control arms, motor mounts, transmission crossmember, driveshaft, halfshafts, uprights, hubs, steering shaft, and headers - on the first round of swap part releases. Much more will be developed after that "Stage 0" round of major parts is in production (like plumbing, cooling, wiring, and fuel system solutions). These bits will only be available after this car is road tested. We will post up a few more times before that happens, so just subscribe to this thread and you'll be the first to know. That's how we've done all of our BMW kits (120+ kits sold) in the past - get a car built, then release the major drivetrain related mounting bits + headers, then release the sub-system solutions after that.

                  More soon,
                  Terry Fair -
                  2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                  EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


                  • #10
                    Re: Vorshlag Miata LS1 Alpha Project

                    Project Update for November 11, 2015: It has been a long time since my last update on the Alpha Miata LS1 swap build thread, so we have a lot to cover in this update. This project was on hold for a while, but was put back on the schedule in July. Since then the front and rear suspensions were wrapped up enough to put the car on the ground, wheels and tires mounted and tested, bodykit mocked up, engine's intake and accessory drive finished, and more.

                    Our first LS1 powered Scion FR-S (shown above right, next to the LS1 Miata) was completed enough for the customer to start driving it during that 6 month hiatus in the Miata project, and we developed some new things on that swap that will help us on the Miata. The FR-S recently came back for some follow-up development and I will update that build thread soon.

                    Difficult Realizations

                    There were many things going on behind the scenes that held up progress on this build for the first half of 2015. Obviously this project has moved beyond the original scope, because it became much more than just a "bolt in swap kit".

                    As we moved from section to section and addressed the weak points, the project began to fall well outside the realm of just a V8 swap kit. We were dedicated early on to removing all of the weak links that we often see fail with track abuse in other V8 Miata swaps, namely the front hubs and rear hubs, the rear halfshafts, as well as the need to upgrade the OEM brakes and control arms to deal with massive engine torque and tire grip. Addressing those issues in a kitable format was going to take serious added engineering and fabrication hours, more than we could every hope to recoup with kit sales. So the decision was made to do this car as a one-off, making both the engineering and fabrication easier and saving hours and hours of unbilled development time.

                    The customer and I had a good conversation in late June, after we both did some research into other Miata V8 swap costs. This is when we realized where reality was: With many turn-key swaps for V8 Miata's costing $50K (minus the chassis), our revised numbers for a one-off build didn't look so far out of the realm of possibility. We all agreed to some compromises and then moved forward. This delay ate up several months this year but we were back on track late this summer.

                    Does that mean we will no longer offer the finished work in kit form? After a hard look at the costs, I doubt it will be at a price point most people will want to pay for a home-built swap kit. Of course we can replicate these parts on the Alpha V8 Miata as a turn-key installation for others. Will it be cheap? No, but it won't be out of the range of other turn-key Miata LS1 swaps.

                    I feel that the end result will make for a pretty durable and damned fast track car that can still be street driven. It might end up being the only Miata V8 ever build to this level of insanity (this customer asked for "crazy"), but that's not necessarily a bad thing either. Let's look at some progress!

                    Rear Suspension Change and Major Progress

                    The final steps of finishing the rear suspension were pretty tricky on this car. Due to some challenges we had to think outside the box to get to the finish line.

                    We have taken a car made for small brakes, small halfshafts/hubs, and small wheels and tires and jammed a massive 8.8" Ford diff in there, big aluminum uprights from a RWD V8 powered production car, and are building all of this around an 18x10" wheel and 285/30/18 tire out back.

                    Once the custom upper and lower control arms were built and the halfshafts mocked up, it was clear there was not enough room for a coilover rear shock and spring in the normal location. We tried it upside down, right-side up, moving the upper and lower mounts this way and that - no chance. The rear suspension upright layout we are using made it impossible to fit the spring and shock there.

                    It was just a matter of space - there wasn't enough of it. So I decided to change the rear shock layout into a pushrod/bellcrank style, and move the spring and shock into the trunk. What the what?!

                    This took a lot of work - mock-ups, calculations, CAD design, CAM programming, CNC machining, fabrication, and testing - but it is in place and we now have the shocks mounted in the trunk. The suspension moves up and down and all of the motions look good, and everything is overbuilt and strong.

                    A big chunk of billet aluminum was used to make the pair of bell cranks in multiple steps on the CNC mill, which was a good use of our new CNC machines and skills that we added in January 2015. We bought CNC machines to make ALL of our production Vorshlag components in house, but this also allows us to make custom one-off things like these Miata rear bell cranks.

                    We didn't go to pushrod actuated inboard suspension to be cute, but out of necessity. The bigger, stronger rear suspension and driveline parts we felt were warranted in this V8 build just ate up too much room, and we had to spend more hours to move things around (most of which were unbillable development hours).

                    I will go into more details on this rear suspension once we have done some road testing, but so far I'm happy with the results. The bell cranks were CNC machined in custom fixtures over 3 operations to make the completed bits. Radial ball bearings were installed for the pivots and rod-ends are attached at each end of the bell crank - one to the pushrod and the other to the shock.

                    The front shock we had already built was used for the rear mock-ups and the length/stroke were pretty spot on for the rear, with the motion ratio of the bell crank and pushrod location on the rear control arm.

                    The rear control arms had double-shear pushrod mounting tabs added, then the pushrods were built, and the whole setup was then tested through the full range of suspension motion. Once that was confirmed the rear control arms were final welded.

                    We have fixed length mock-up rear shocks in place for the moment, but another pair of Bilstein ASN coilovers will be built to wrap up the suspension soon. Now we can at least check ride heights on the ground, start tire mock-up, and move forward on other systems with what we have in place.

                    The fuel filler neck will be relocated inside the trunk at the left corner, to leave room to load luggage for use on road trips. This car will not carry a spare tire, so some of the brackets that are used to hold the jack and temporary spare will be removed to add some much needed trunk volume.

                    The rear shock mounting is probably the craziest part of this swap, but again, it was the right solution for the constraints we had.

                    Engine Completion Work

                    The built LS1 longblock that we have had in place for a while was finally dressed out with many missing intake and front accessory parts in recent months. First up was the coil packs and brackets, which were purchased, assembled and installed.

                    There are a number of various coil packs and coil pack sub-harness ends made for GenIII and GenIV LS series engines, but if you order the main engine harness correctly, it doesn't matter which you choose. We went with F-body brackets, sub-harness and coil packs. These bolt to 1999-02 Camaro LS1 valve covers, where I used button head stainless M6 bolts to hold them in place.

                    The LS2 intake manifold and throttle body were installed next. I explained in detail why we used an LS2 intake and throttle body on the Alpha Fr-S in THIS POST, which you can go back and read - because it also applies for this car. Basically the LS2 manifold has the same cathedral port shape as the LS1 heads on this motor, but it has the "short" drive-by-wire throttle body needed to clear the hood. If we would have used an LS3 motor the LS3 intake manifold and throttle body would have been the obvious choice. Cable operated throttle bodies are much longer and would not clear the hood line.

                    continued below
                    Terry Fair -
                    2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                    EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


                    • #11
                      Re: Vorshlag Miata LS1 Alpha Project

                      continued from above

                      The front engine accessories and their mounting brackets were also finalized and installed. This car is being built without power steering, and we had originally mocked-up Pontiac G8 LS2 accessories - the same that the Alpha FR-S LS1 used - since that car has electric steering. These cars have very different engine bay shapes and widths, and on second look the 4th Gen F-body LS1 brackets, accessory layout and front drive pulleys were more appropriate, so we went that route instead.

                      A new water pump, alternator, brackets, tensioner and idler pulley were procured, along with GM sourced hardware to attach all of this. I will show more details on the serpentine routing to bypass the power steering once the harmonic balancer/lower pulley is here (ordered weeks ago but on backorder), but the picture below shows the normal 4th gen LS1 belt routing - with the power steering pump in place. We have already changed the smooth idler pulley to a 6-ribbed pulley, which I installed with an 1/8" spacer to line up to the main belt "plane". Saw this on Yellow Bullet - those drag racers don't need no dang power steering.

                      Long story here (back ordered part), but we're waiting on the correct SFI-rated front harmonic balancer and pulley for the 4th gen Camaro belt placement (there are 3 or 4 different belt placements for LS engines, front to back). The one we have installed now (shown below) was for the G8 accessory belt offset, which is about 1" too far back for the F-body accessories.

                      Rear Wheel Hubs Modified

                      The rear suspension uprights we used are a popular Ford Racing part made from a production Ford vehicle, and it is often use on Cobra Kit cars. These are made for Ford hubs, and we used the 31-spline 2003-04 Mustang Cobra hubs, which have a 5 x 4-1/2" bolt circle (5 x 114.3mm). This was a proven, durable, and readily available package. This Ford rear flange made perfect sense when the front suspension were going to be based around Mazda RX8 hubs/uprights/control arms. Ahh, the early days of this project were so simple...

                      Now we have Corvette front uprights and hubs, which use a GM 5 x 4-3/4" bolt circle (5 x 120.65mm), which doesn't match the rears. When we moved to the Corvette spindles we planned on modifying one end or the other so that the bolt patterns would match, and now was the time for this change.

                      The guys removed the rear hubs from the uprights and Jason machined a custom set of soft jaws for the CNC mill to secure them in place. Then he installed the first hub, zero'd the machine on the hub center and face, programmed 5 new holes on the GM 5 x 4-3/4" bolt circle, and drilled them with the CNC. Instead of the pressed-in "splined" wheel studs that were used before (Ford still uses 1/2" stuff), we made these for screw-in wheel studs in a GM thread pitch and diameter...

                      Once out of the CNC vice, Jason tapped the newly drilled holes in both hubs for M12-1.5 thread pitch, then Olof installed Vorshlag 90mm wheel studs made for a BMW. We have these wheel studs made to our specs and sell thousands every year. GM and BMWs use the same stud and lug nut diameter and thread pitch (M12-1.5). Proven, tested, safe. Yes, they are long, but if we ever need to use spacers we have the room. This car can also be used in Gladiator races.

                      A drop of red Loctite is used when torquing these 90mm studs into the hubs, just like when installing them in BMWs. When installed correctly we can "zing" lug nuts off with an impact gun, with no issues. The completed hubs were then installed back into the rear uprights and the assemblies went back into the rear suspension. Now its time to mock up some GM bolt pattern wheels!

                      Ugly. I first tested with some C4 Corvette 17x9.5" wheels and 275/40/17 tires (the OEM wheels that were on my 1992 Corvette when I bought it). These are much taller tires, the wheels had the wrong offsets, and were not useful in mock-up at all. We looked around the shop and then found the perfect set to test with - which would allow us to drop the car on the ground for the first time in a LONG time...

                      Down on the Wheels + Flare Mock-up

                      This was a big step just a few weeks ago, with the Miata placed down onto some decently sized wheels and tires with the new custom front and rear suspension setups. Damn happy that this car now rolls...

                      This time Ryan installed the race wheels and tires from my NASA TTC classed 1992 Corvette race car. Due to class restrictions we run that car on a 245mm tire (Hoosier R7), but its a BIG 245, with 9.7" of tread width. These tires are mounted to some lightweight SSR 17x9.5" wheels with a GM 5-lug bolt pattern. The mock-up tires (245/40/17 Hoosier) are still too narrow for this car's power level, but they were 24.3" tall and somewhat similar in width to what we will end up with (285mm on 18x10" wheel).

                      The Miata's owner provided this wide body kit, which is a fiberglass reproduction of a popular NB flare kit. It has 4 flares, a new composite nose (not yet fitted) made for NB2 headlights, and side skirts to tie it all together.

                      The styling of this kit looks odd in these mock-ups, but once painted and "fitted" they work fairly well. The race car shown below has the same kit. We saw this at a recent track day at MSR-Cresson and it used 275/35/15 Hoosier race tires on 15x10" wheels, which is super short (23.0" tall) and easy to fit onto these cars with this body kit.

                      Ultimately we're still shooting for a 285/30/18 tire and an 18x10" wheel. Why not go with the proven 275mm 15" Hoosier that fits this body kit? Two reasons. First its narrower, but more importantly there are ZERO street tire choices in this size or anything close to it. There is a Hoosier race tire and... nothing else.

                      The 285/30/18 tire shown above is fairly popular for racing use and gives the owner over a dozen choices in street tires + several DOT-R race rubber choices as well. We will have to modify the front frame horns for the taller 24.9" diameter tire, to have adequate bump travel, but we always knew that. This 285/30/18 size is really the best option: super short for the width and wheel diameter it has, with a lot of tire choices.

                      And yes, the images above shows the Miata and the 17x9.5" wheels with some serious "poke" past the front flares. The front and rear tracks were measured identical here, but the body kit's flares have much wider rear flares than front flares. Still, we managed to address this issue earlier this week, by adding some much needed front negative camber. See below.

                      Front Suspension Progress

                      The initial suspension measurements and mock-ups were done "in the air" but once the car was sitting on all 4 wheels and tires at ride height, it was obvious the front needed a tweak to the upper control arms to get the static camber settings in the right range.

                      These were the last arms to be final welded, and were only tacked in place. It was assumed that there might be some adjustment once at ride height. The upper arms were removed, shortened, mocked up then final welded earlier this week.

                      The car now has -3° camber front camber and adjustments to go up and down from that range. Side benefit - which we knew would happen - is that the front tires now fit under the flares much better.

                      Next we will measure the existing 17x9.5" wheels and look at how far we can go inboard with an 18x10". Then we will order up some Forgestar custom 1-piece wheels in this size and add some 285/30/18 Hoosier A6 tires that were acquired for mock-up use.

                      The Miata will eventually be built on 285/30/18 tires from the new "magic" 200 treadwear sticky street tire options... but instead of buying those NOW, it makes more sense to wait until closer to completion, as tire options and supplies change every quarter. Who knows what uber-tires will be introduced in a few months for 200 treadware tires? There are Tire Wars in process!

                      What's Next?

                      We have the supplies on hand for making custom headers, supplied by Magnaflow. These 1.75" primary mandrel bends, 3" collectors and LS1 flanges will be used to make the headers soon.

                      The driveshaft has to be built first, so the headers and exhaust can route around that. Some Miata "rail stiffeners" and a "butterfly brace" will be added first, to make sure everything routes nicely together - braces, driveshaft and exhaust.

                      Rear brakes are also being address very shortly. C5 Corvette rear brake rotors (see above) were ordered and should be here any day. We already have C5 rear calipers and pads and plan to make brackets to mount these to the rear uprights that are in place. Then we can move onto plumbing the brake and clutch hydraulics, have the wiring harness built, and more.

                      More soon,
                      Terry Fair -
                      2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                      EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


                      • #12
                        Re: Vorshlag Miata LS1 Alpha Project

                        Project Update for April 28, 2016: It has been another long break since my last update on this Alpha Miata LS1 swap build thread, but we have made a ton of progress since then. We have so much work to cover that its going to take a number of installments, but I've been buried with work and am behind on the build thread. One thing I wanted to point out - this is not going to be made into a kit, because it would be so costly as to be unattractive to almost everyone. We cut that goal shortly after my last post and that sped up this build considerably.

                        In the next handful of updates we will cover the custom exhaust headers, the custom DSS rear axles, custom driveshaft, we switched transmissions (again!), made a customized shifter and trans tunnel cover, installed the Air Con, ordered and installed the wiring harness, removed the fuel tank and started plumbing that system, custom built a radiator and installed that, built all of the cooling hoses, mounted a remote coolant reservoir, mounted the C5 rear brake calipers, built the remaining two shocks and installed the springs, added a C6 electronic throttle pedal, modified the booster to mount a C5 brake master cylinder, made an adapter to fit a Tilton clutch master cylinder, and dug into the wiring of the motor and gauges. We also spec'd 18x10" Forgestar wheels, got those in, and mounted 285/30/18 Hoosiers (tires only being used for mock-up and fender mods). Whew! Lots to cover, so let's get going with the first update.

                        MORE TRANSMISSION FOLLIES

                        One of the things that happened right after my November post was a change of transmissions... This project has been a real ball buster with respect to the transmission! The initial desire on this swap was to avoid the transmission tunnel mods needed in other V8 swap kits. This seemed like an extra burden that would prevent DIY mechanics from doing this swap at home, and in fact that has been a common complaint from many V8 Miata swappers. Funny enough, none of this matters now that we blew off the "kit" plans.

                        Still, hacking up the tunnel seemed unnecessary to me if we were willing to make a custom front crossmember - which we did, and that added LOTS of room to move the engine lower than the kits out there. Modding the tunnel would mean removing the entire dash and interior, cut and slice the floor pan, weld in some new sheet metal, then stitch weld that all back together to clear the T56 - as is done with the other V8 Miata kits. We thought a move to the Tremec TKO 5 speed would be beneficial and tried that... but ran into some packaging difficulties. Then we tested a 4th gen Camaro T56, and that worked, so we built the kit around that.

                        4th gen F-body T56 and bellhousing attached to the final LS1 engine

                        After we had the engine mounts and crossmember developed around the 4th gen T56, we ordered a brand new T56 Magnum. Now this term "Magnum" is bandied about freely, but there are a lot of definitions of a "T56 Magnum". This is where a mistake happened... and damn it, I know better.

                        This is the real T56 Magnum, brand new and available from Tremec for T56 applications...?

                        New T56 Magnums are the unit shown above, available from Tremec, which has a different front to back length and different shifter location than a 4th Gen F-body OEM T56 (1998-2002). Those differences are big but are NOT clearly shown in their catalogs. These are images of the two T56 models and they don't even measure them the same way.

                        The T56 Magnum version is stronger and more readily available - the 4th gen F-body T56 has been out of production for going on 7-8 years. We tend to use T56 Magnums in our BMW V8 swaps, but it only requires a driveshaft change. Otherwise you end up hunting in junkyards for F-body length T56 units, but they are so old by now they all have to be rebuilt... in the end you spend more rebuilding an old T56 than buying a new T56 Magnum.

                        There are many shops, however, who sell upgraded F-body T56 transmissions as a "T56 Magnum" edition. They are dimensionally different than brand new T56 Magnums made by Tremec... and often have different input or output shaft lengths and spline counts. We get customers ordering the wrong BMW V8 swap driveshafts because of this "Magnum" name being mis-used.

                        What these two Tremec catalog charts don't show is that the location of the shifter is very different between the F-body T56 and the T56 Magnum. Notice how "A" is measured differently in the Tremec catalog? Well this is a real mess that Tremec should fix in their literature, but they stopped selling the F-body T56 about 6-7 years ago and its not been listed in their catalog since 2009.

                        Left: The T56 Magnum shifter location is too far forward (inside the dash!). Right: 4th gen T56 is much better!

                        After we received the new T56 Magnum our crew installed it into the car. I looked in the stock shifter hole (above left) and saw that it was waaaay too far forward. Not good. I admit to uttering a few choice words. The T56 Magnum has a shifter location that is about 3" farther forward compared to the 4th gen. Again, I had figured this out in 2008 but somehow forgot this key piece of knowledge. In the BMW V8 swaps it never mattered much (there was plenty of wiggle room in the tunnel/console). On the Miata the Magnum shifter base is inside the center stack of the dashboard, so I had to punt.

                        I took a used 4th gen T56 mock-up transmission I had in the shop and asked our friends at Dedrichs Motorsports to completely rebuild it.

                        Now this T56 brand new, upgraded, and most importantly - has the shifter in the right spot! It has a new input shaft, main gear cluster, synchros, and all new bearings and seals. Even most of the gears had to be replaced. Using the T56 Magnum with the as-built shifter location would just not work - we would have had to move the engine back about 3 inches, which would require serious firewall and tunnel mods that nobody was keen to do.

                        Oh well, live and learn. This one is 100% on me and I had to eat the cost difference between the two T56s (and some labor hours), but we will use the T56 Magnum on another V8 swap project we will tackle soon. At this point we could at least move forward with the custom exhaust header development, driveshaft construction, and exhaust system layout. The T56 debacle held us up for a couple of months but Joe at Dedrich's Motorsports went through our old T56 and made it a new monster inside.

                        I'm skipping ahead a couple of months here. We purchased the Hurst 6-speed for the 1998-02 Camaro T56 and put it in the car, knowing it would likely need to be modified at the base, handle and such. The Miata trans tunnel opening had to be notched a bit on the leading edge, too.

                        To cover up the now over-sized transmission tunnel hole Ryan made a piece of aluminum plate to fit, which bolts to the tunnel and is notched to clear the Hurst shifter and adjustable 3/4 shift stops.

                        The shift handle was still too far forward so Ryan modified both the base and the handle to offset them rearward and angled back towards the driver. This made the shifter fall closer to hand and eased the interference with the stock center console opening.

                        We also ordered a Joe's Racing fire proof/Nomex shift boot and frame, which we install on virtually any car we build with a V8 swap. This helps seal up any opening in the tunnel, to make that opening fire proof and to reduce heat and noise transferred to the cabin. These come with an aluminum frame that has snaps built around the edge and the Nomex boot snaps over that. In the above right picture I pulled the shift boot down over the modified handle for the picture, but it slips up and has a velcro connection to close the gap around the shaft.

                        Here's a picture of the same Nomex shift boot added to my C4 Corvette recently, as well as some thermal / radiant barrier near my leg (no interior to shield heat from exhaust/trans). It can be used to completely replace a factory boot, or like we did here, go over the factory rubber tunnel seal. In the Miata it is under the factory leather shift boot. Regardless - its a GOOD IDEA to add one of these ~$90 fire proof shift boots to any race car or any car with a modified tunnel opening.

                        The original factory shift boot was old and torn so a brand new Mazda sourced leather shift boot was purchased. This is going to be street driven and have a full interior, of course. This Nomex shift boot will all be hidden under the leather boot. Other than that, the transmission just needs a shift knob and some fluid, plus the reverse lockout wiring and speedometer connection.

                        Once the transmission was in the car and finally "locked down" the driveshaft, so that could be spec'd and ordered. We got it about a week later and installed that.

                        That was installed for fitment checks and exhaust routing, and it looked perfect. Big 3.0" diameter aluminum unit rated for 600 hp, so it should be fine with 475 whp.

                        BRAKE WORK

                        Shortly after my last post the C5 Corvette rear rotors arrived. These are StopTech/Centric Premium blanks (the "Premium" version gets you powder coated centers instead of raw cast iron - no rusting) which are 12.0" in diameter and 1.0" thick, which are the same rear brakes on all C5 generation Corvettes (1997-2004), from the base models to the Z06.

                        When we had the rotors in hand and the rear hubs re-drilled for the GM bolt pattern Ryan mocked up the C5 rear calipers and brackets (above). Making the actual bracket to mount these correctly didn't happen until several months later. Initially we were going to measure then CNC machine these on the mill, but our machines and engineer are so tied up making suspension products it fell onto Ryan to fabricate these in April.

                        First the calipers, pads and slider brackets were mocked up on the rotor and aluminum upright, on the fab table.

                        Then came hours of measuring, cutting, welding and juggling of thicknesses to get the calipers mounted in the right radial and lateral positions relative to the rotor.

                        Other than the flex lines to connect to the rear hard lines, this C5 rear caliper / C5 rotor / 03-04 Cobra rear hub swap is done.

                        Since the front brakes are C5 and the rear brakes are C5, I had the obvious idea of ... using a C5 Corvette brake master cylinder to actuate the calipers. Kind of a no-brainer, right? I asked the guys to yank the Miata brake master off and I did some measuring...

                        We had a C5 in the shop and the stock C5 master looked dang close. So I ordered a C5 master cylinder as a test...

                        Sometimes I'd rather be lucky than good! All it took was shortening the "stem" from the booster/pedal and just a kiss of hole enlargement on the C5 master cylinder mounting flange and it slid right into the Miata booster. Win!

                        Now that the brake master was handled Ryan tackled the task of adapting a Tilton master cylinder to the firewall for the clutch hydraulics. Yea, its not "Brake system" but its pretty close, so roll with it.

                        Just like on the FR-S LS1 swap, Ryan made a billet aluminum adapter to go from the firewall bolt spacing of the Miata clutch master to the Tilton mounting flange. He made it so fast I never got a picture, so the pics of FR-S parts above will have to do (similar in design).

                        Once the firewall adapter and pushrod changes were made the Tilton clutch master cylinder was functional. This will change the hydraulic ratio of the clutch circuit using a larger diameter master cylinder that we've used in the past and know works with the clutch we're using.

                        That's the firewall line-up with the Tilton clutch master, firewall adapter, the C5 brake master. There's wiring and fuel system plumbing shown, but I wanted to keep this post short and sweet so I will cover that and MUCH more next time.

                        Thanks for reading!
                        Last edited by Fair!; 04-29-2016, 09:56 AM.
                        Terry Fair -
                        2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                        EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


                        • #13
                          Re: Vorshlag Miata LS1 Alpha Project

                          Project Update for May 12th, 2016: In an effort to get caught up to "real time" on our LS1 V8 powered 1999 Miata project I'm going to keep cranking out the build thread updates. In this round we are going to cover the custom full length stainless steel header fabrication work, which was a challenge but came out great.

                          I will also cover the work involving the starter, front drive accessories, radiator, coolant lines and remote coolant reservoir in this post.

                          STARTER SELECTION

                          We always try to build our LSx swap kits so they can re-use the factory starter, which is a fairly large direct-drive unit (see below at left). They are relatively large, somewhat inexpensive, and sturdy. The truck LSx starters are different and there are many stories of these breaking the flange off one side. Truck LSx parts are almost always NOT what you want to use for a performance build.

                          We had some serious space constraints in this engine bay when we were planning out the full length headers so Ryan spec'd out a gear reduction starter (see above right). As opposed to a direct drive starter (as most OEMs use) a gear reduction starter goes through a gear box to multiply torque (in this case 4.4:1). That gear reduction adds a lot of starting torque and is a common upgrade for higher compression engines (also common as OEM on older Chrysler V8s and many import engines). These also weigh less (8 pounds vs 11), take up less space, last longer, and do not have as much "heat soak" problem as a direct drive. They can cost more, though: the Powermaster 9509 which we used was $239, whereas the OEM style starters are $90-185 (in varying degrees of Chinese import quality).

                          For our now "one-off" V8 swap we were no longer constrained to the stock 1998-2002 Camaro LS1 starter, and the Powermaster gear reduction unit gave us some much needed space (several inches shorter) for header routing. It will become apparent in the header section below why this was needed...

                          FRONT ACCESSORY DRIVE

                          Many of our V8 swaps utilize the 1998-02 Camaro front accessory drives, for 2 reasons. First, early on when we started doing our first LS1 swaps (2002) these engines were the most PLENTIFUL and the least costly of the aluminum LS series engines. Second, as we have found over the years, the Camaro front accessory drives were also the most COMPACT laterally.

                          4th gen Camaro LS1 accessory drives have the NARROWEST width of any LS engine. This is in an E36 BMW with power steering.

                          There are about a dozen different LS front drive arrangements - many trucks, GTO/CTS-V LS1, LS2 Cadillac and G8, C5 Corvette, C6 Corvette, etc. We keep coming back to the 4th gen Camaro bits because they just fit better, width wise.

                          On the FR-S we had some serious front to back space constraints, and the G8 accessory drives (above and below) fit that car the best. The engine bay is short yet VERY wide in the FR-S, so any extra width in the front accessories wouldn't be an issue. Like the LS2 Corvette bits, the G8 pulleys and accessory placement were shorter front to back - by about an inch.

                          Well the engine bay in the NB Miata is totally different, and like so many of our other swaps it is narrower but doesn't have a massive front-to-back clearance problem. It came with an inline 4 that is about as long as the V8. The FR-S has a boxer 4, which is short and CRAZY wide.

                          We actually mocked up the G8 accessories from the FR-S in this car (it was the mockup engine, actually). And while these accessories technically fit, the Camaro bits fit better. I'm just showing this in case any of you ever do a home brew V8 swap in an NB - these pictures above might give you some ideas of what fits.

                          At one point in this build I decided to switch from G8 to 4th gen Camaro accessories, but of course we already had the SFI balancer for the G8 front drive. Easily fixed - the Camaro style balancer was ordered and installed on the Miata's LS1. The 4th gen Camaro balancer has different spacing front to back, and extends farther forward to match the Camaro pulley placements.

                          Left: G8-depth Powerbond SFI balancer. Right: Camaro depth Powerbond SFI balancer (note the deeper dish).

                          I like the cost-performance benefits of the Powerbond SFI balancers, and my engine builder approves. Your engine builder might have some magic witchcraft brand of SFI balancer they want to use - which is fine. Just use a quality, SFI balancer over an OEM balancer, and everyone wins.

                          I am not a fan of the torque-to-yield OEM crank balancer bolt for the LS engines, so we always use the ARP replacement bolt when installing the balancer. Pro tip: find an old OEM LS7 balancer bolt to use for LS engine balancer installation. The LS7 bolt is considerably longer and will help "pull" the balancer onto the crank snout (its a press fit) without stripping the threads - since the longer bolt will have more thread engagement at the start. Once you have the balancer pulled onto the snout about an inch, swap in the proper length ARP crank bolt (and appropriate thread lube) and tighten to the specified ARP torque. We paint mark all critical bolts here at our shop - a good practice to quickly see if something has backed off.

                          Since this car will not have power steering (we have "de-powered" the Miata rack), that means we need to bypass the power steering pump pulley in the serpentine belt routing. A quick look on the interwebs led me to the YellowBullet forums, where some trusty drag racers had sorted out this trick ages ago with the 4th gen Camaro accessories. There is an idler pulley you change, a bushing that gets machined, and the belt routing goes as shown above at right.

                          Of course they neglect to mention that the belt gets VERY close to a bolt head near the bottom of the alternator bracket, so we are changing that one bolt out from an OEM extended flange hex head bolt to a button head bolt, for the necessary belt clearance.

                          We used the A/C compressor and tensioner + idler pulley from the 1998-02 LS1 Camaro as well. This fit with a lot more room to the frame rail than the G8 bits, giving us more clearance to make the wiring and plumbing connections.

                          I didn't have pictures from when we originally installed the compressor, so these are from much later (and after the headers were built). All of the accessories have to be in place to design the headers around, as well as the radiator and hoses. Once all of the accessories were all in place it was time to build the headers...

                          CUSTOM HEADER FABRICATION

                          Normally when we are making an "Alpha" car that we want to make a kit from we need to make a prototype exhaust header, which we build around our production header manufacturer's CNC tubing bender dies. There's a lot of other constraints we have to build around, and it is actually a giant pain in the butt. But since we had realized "nobody is going to buy this kit for what it will cost", and moved this to a "one off" build, things sped up considerably.

                          We sourced some stainless U-bends and LS1 exhaust port flanges from Magnaflow, then realized we needed more and got some more stainless bends from another source. They had two different bend radii, normally not allowed with a CNC bent production header, but since it was a one-off - didn't matter. This gave Ryan a bit more flexibility to design the header better for this car, too.

                          Ryan got to work on the header mock-up. The exhaust flanges were bolted to the heads and the collectors were placed down at the bottom of the engine bay where he wanted to end up. He started on the "hard side", which is almost always the driver's side, using our ICE Engine Works plastic header modeling kit - which you've seen us use in all of our past custom header builds.

                          Working around the steering shaft is always tricky. At this point the steering shaft had the correct lower U-joint and a piece of 3/4" Double D shaft, but the top was just mocked up in place (we've since received the upper U-joint and built a 2-piece collapsible shaft). After the 4 tubes were completed in the snap-together plastic bends, he takes a tube out and copies it in mandrel bent stainless steel tubing... cutting, splicing, tack welding it together.

                          Making the tubular front crossmember opened up a LOT of room to run a proper full length header, and even though this is not destined for a kit, it IS the right way to do this V8 install. Not the most economical decision for us (since we ate tons of "kit development" time making these), but at least the header design was not too compromised trying to work around a hacked up OEM stamped steel subframe.

                          It takes a lot of hours to make a set of headers, but that's what it take to make them right.

                          The completed driver's side header has some funky bends, but those are to clear the steering shaft - which passes through the middle of the 4 tubes. We don't needlessly add tortured bends to try to meet a perfect "equal length" design standard, as we and our engine builder have seen - this almost doesn't matter at all on a long tube, street car header design. We design around the theory of using the LEAST number of bends and the smoothest path to the collector, with a long-ish primary length in a "big enough" primary size. These are built with 1.75" dia primaries and a 3.0" dia collector.

                          continued below
                          Last edited by Fair!; 05-12-2016, 11:49 AM.
                          Terry Fair -
                          2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                          EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev


                          • #14
                            Re: Vorshlag Miata LS1 Alpha Project

                            continued from above

                            The above two pictures show the short gear reduction starer and why it was needed. This side's header was constrained and had to snake between the starter and the motor mount shown above right (which was shot later after it was final welded). You might notice that one of the header tubes changed from left to right, too.

                            These show even more constraints on the passenger side - the frame rail and the lower motor mount platform at the subframe. This side ended up being much harder than the driver's side on this car. Ryan designed and built the entire driver's side header and 3 of the 4 tubes on the passenger side.

                            Unfortunately Ryan got buried on the tube framed 69 Camaro build so one of my other techs finished that last tube and final welded both headers. The headers were sealed off and back purged with Argon during final welding. This is a multi-step process where each tube is welded as much as can be reached while assembled, then each tube is cut away from the flange and collector. Then the inaccessible areas are welded, the tubes go BACK into the flange and collector, and they are welded at the ends. In that together-apart-together welding things can shift so you have to test fit the header into the car before it is final FINAL welded.

                            Well... things didn't go exactly to plan and months later when we were putting the car together, the one header tube Ryan didn't make was hitting a motor mount in several places. I probably shouldn't show this, but its the reality of switching between fabricators on a complex job. I don't blame the other tech, as he jumped into the middle of a project and tried to finish it. Its my fault for pulling Ryan off of a fabrication I should have let him do from start to finish.

                            When Ryan was free he cut out the tube with clearance issue and made a new one from scratch, on my dime (not the customer's). In the end the completed long tube headers came out great and will make a nice bump in power over the little super short "block hugger" headers so many swaps use. There's good reasons why we go to all of this trouble: HORSEPOWER.

                            Here's a good example: The bone stock but 100% rebuilt 4th gen Camaro 5.7L LS1 V8 engine in the FR-S swap (above - and yes, I need to update that build thread) made 372 whp with headers we built, through emissions legal cats and a BRZ-spec Magnaflow rear exhaust (which that customer insisted on re-using). This engine uses a stock 1998-02 Camaro cam/head/bottom end which we changed to an LS2 intake + throttle body and our full length 1.75" dia headers. Normally a 5.7L Camaro makes 300 whp through stock manifolds / LS1 intake. So between the LS2 intake and our headers it picked up over 70 wheel... not too shabby. We'll see soon enough what this BUILT 5.7L LS1 makes in the Miata with the same headers and LS2 intake. It has forged internals, big cam, CNC ported headers... should be fun.

                            The headers are finally fitted, fully welded, and installed for the last time. Ground clearance looks excellent and we have started building the after-header exhaust (see pic at bottom).

                            COOLING SYSTEM PARTS

                            The cooling system for this car was always planned to have a "rolled" radiator, for clearance issues up front and potentially for use with a ducted hood down the road - if the customer so chooses. We needed to also put the radiator as low as possible to allow for an "over the top" cold air intake tube. Specifically the LS3/LS7 Corvette factory inlet tube used on many Miata swaps (hey, if it works...). Once we got the engine and radiator in place it made sense why this air tube routing was popular - but I'll show that work in another post.

                            When the top of the radiator is lower than the highest cooling passages inside the engine you HAVE to use a remote coolant reservoir placed higher than any point in the cooling system. Otherwise the cooling system will have an air bubble inside the engine that is impossible to bleed - which will make for all sorts of trouble. Unlike on the E36 LS swaps we've done, we skipped the custom aluminum reservoir tank for an OEM plastic unit with a built in pressure cap, shown above. It was more cost effective and we've used this exact tank in harsh conditions many times - I know it works.

                            See how high in the engine bay the reservoir is placed? To make this fit inside the NB Miata engine bay at the highest point, Ryan fabricated a few brackets and mounts. The bottom of this particular tank needs a "spade" mounting socket, so Ryan built a tower (above right) with a slot in it. The left side of the tank mounts via two bolt holes, which he made on a bracket with a pair of nut-serts added (see above left). When we add the heater hoses from the water pump to the firewall, there will be a "T" in one of them that feeds into this reservoir... which will tie it into the cooling system.

                            I showed this picture last time when going over the driveshaft, but now I'm showing the Griffin radiator. This company has a massive catalog of aluminum radiators shown in CAD drawings that they can make to order. Ryan spec'd out one from their drawings that had an unusual shape at the bottom and a core size that fit our unique front crossmember. It also had a dual-pass design that kept both the inlet and outlet on the right side, which is easier to package for LS engines. We placed the order and a few weeks later it arrived, complete with aluminum shroud and fan.

                            The drawing Griffin provided was spot on and the oddly shaped radiator fit perfectly into the front subframe extensions that were built.

                            Ryan built a sheet metal lower radiator bracket with some dimple dies to give it some strength. This bolts to some some radiator mounts that attach to the subframe tubing, as shown above. There are rubber bushings between the lower bracket and the aluminum radiator - which has a very thick core for better cooling capacity and efficiency.

                            The radiator is canted forward at the top and tucks under the stock upper radiator support. Again - a quick hole added in the hood would allow for excellent venting of hot radiator air, if the owner ever wants to go that route. A splitter added to this setup would work much better with the vented hood, too.

                            The aluminum shroud and fan help with cooling in hot Texas summers with the air conditioning cranked. The aluminum shroud bolts to the radiator, and it has enough structure to also be a good place to bolt some upper radiator brackets to. These attache with stainless button head bolts into nut-serts added to the factory upper radiator support. A straight Canton billet aluminum upper coolant "water neck" holds the thermostat and points the upper hose to the radiator neck. The OEM water neck is cast aluminum and angles differently.

                            The rest of the cooling system shown in this post has to do with the radiator hoses (we'll tackle the heater hoses in another post). The picture above left shows the proposed routing for the upper and lower radiator hoses, color coded to show the hot and cold water paths. The upper hose was made from some straight aluminum sections and 90 degree silicone hose bends.

                            The lower radiator hose routing proved tighter than the silicone hose bends could handle, so Ryan customized the lower neck at the radiator instead.

                            A tighter aluminum tubing bend was added to the lower outlet of the radiator, which had a better fit than the straight outlet had. Since the bottom of the radiator is closer to the engine than the top this was just the best way we could think of to make it fit and still have good coolant flow. The lower hose was then built and buttoned up the bulk of the cooling system.

                            WHAT'S NEXT?

                            There's still plenty of completed work to cover in the next post. In real time we're wrapping up wiring and fuel system plumbing, and very close to bumping the starter. We've also got a roll bar installed, drop floor pan installed, several frame bracing mods added, racing seats and harnesses, and the suspension is wrapped up.

                            Today the custom stainless exhaust is being tack welded together and should be coming off for final welding this afternoon. We are "ones of days" away from firing up this beast.

                            More next time,
                            Terry Fair -
                            2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                            EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev