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Unread 12-17-2014, 11:16 AM
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Join Date: Jul 2004
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Default 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,
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