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Hello all - My name is Aaron Leichty and I live in Louisville, KY. I'm starting this build thread to share a little bit of my experience building a V8 Miata in hopes that it will enrich the already impressive knowledge base on this forum, and also, I hope provide some motivation for me to continue onward with this build. It often sits in the back of the shop neglected for months on end as customer vehicles take priority. In the next year, I hope to complete my initial vision of what this car was intended to be!
Backstory:
I first laid eyes on this Miata 15 years ago! It belonged to a friend who had purchased it from the original owner in Texas and brought it to Louisville, KY. He was operating an "arrive and drive" Spec Miata program at the time. He had added the Spec Miata Bilstein suspension to this car, but it was otherwise stock. He would use it to take people out on track who were not familar with Spec Miata and introduce them to these great little lightweight sports cars with the hopes they would want to build or race in SM. In short, it was a 90HP turd with shitty SM suspension... but boy did that Mariner Blue paint look good!
Fast forward 8 years and I finally managed to convince him to sell it to me. I fitted it with some Ohlins shocks, 14x7 RPF1, a VVT engine, 6spd, OS Giken, Recaro seat, roll bar and a few other small bits. For two years it was a fun little summer cruiser and occasional track day car to supplement my other two race cars at the time (we can talk about those later). Around the same time, I had convinced my father to purchase a 00' Miata for his track car. Up until then, he had a 450HP Supercharged 350Z for the track and I was getting sick of fixing it for him! He embraced the Miata right away, but would still mention how much he missed the power of the 350Z. He was the first to bring up the idea of V8 swapping the Miata, which I responded by saying, "Those cars are stupid and most are slower than their 4-cylinder counterparts on track! They are an old man's car show novelty. Heck, if you want a V8 Miata they already make them - they're called Corvettes!" That was the end of the V8 Miata discussion for the time being, but a short time later I picked up Carrol Shelby's biography... and that was a mistake. As I read about Shelby's life I was charmed by this idea that pure, blunt power-to-weight could reign supreme over the finesse and sophistication of the Ferrari and other great sports cars of the era. I began to think about the Porsche GT3 Cup Car as representative of the finesse sports car of today; could the V8 Miata be the obnoxious AC Cobra of today?
With GT3 Cup lap times as my reference, I began to sketch out on paper what it would take for a Miata to outpace them. On paper it looked bonkers, but achievable. And maybe, fun? To be completely honest, I wasn't 100% sold on the idea. The other V8 cars in existence were cool to look at, but they weren't exactly hammering out impressive lap times from what I could gather. Nevertheless, I told my father that I would do a conservative V8 conversion for him if he still wanted it. We started by purchasing an LS1 take-out engine and transmission from a Pontiac GTO and we purchased most of the major conversion bits from Shandelle at V8 Roadsters. Since the car was going to be street registered we opted to keep air conditioning, cruise control, and a full interior. We chose to forego power steering due to track reliability concerns (I loathe GM power steering pumps and prefer non-assisted steering on track). Other upgrades already on the car included Ohlins shocks, 949 Racing 15x9's, Recaro seats, StopTech BBK, and an APR GT-250 wing. Fast forward to the finished product and it was actually pretty cool. 341WHP/356TQ is enough to be fun, but nothing crazy or unmanageable. We had to rethink what we thought we knew about Miata suspension setup as the extra torque really changes the way weight is transferred in the car. Once we had it dialed in, there was no way my 4CYL Miata race car could touch this full interior, AC, cruise controlled Miata on track. That may seem obvious now, but up until that point I had seen nothing but slow *** V8 Miata conversions on track making a bunch of noise while running seconds slower than a competently driven Spec Miata!
So back to my GT3 Cup vs V8 Miata sketch: This street car, LS1 build wasn't going to knock off any Porsche Cup Cars but it was quick enough to show that there was some potential for the V8 Miata concept to break into that performance envelope. It also became apparent that it would be a VERY expensive Miata; like expensive enough that you might as well buy a Cup Car? So at this point I still think it's a stupid idea... but I've done dumber things. A few things prompted me to build the car that is the subject of this build thread. One, I had customers now wanting to build cars similar to the one we had put together for my father. I wouldn't feel comfortable building them cars without a development mule of my own. And two, I have the pleasure of working with two extremely talented mechanics whom I felt needed a project that they could really show off their full range of skills on. I thought the car would be a great challenge, but also an "experience" that we could learn a lot from. So, without further ado here she is...
Spec's as she sits:
GMPP LS3 480HP crate engine.
Aviaid 3-stage dry-sump oiling system.
Tremec TR6060 "Magnum" transmission.
Getrag G80 differential.
V8Roadsters subframe and driveline mounting kit
Ohlins DFV shocks w/ 800F/550R rates.
MiataHubs.com billet front hubs.
Stoptech STR-42 calipers.
NoPro fender flares.
Garage Hundred One front bumper.
APR GT-250 wing.
AiM MXL2 dash.
Multiple wheel/tire sets from 15x10 to 15x12; 245 to 295 tire widths.
Lap times:
Putnam Park: 1:09.11
NCM Grand Full: 2:05.44
Goals/Plans for 2019:
Top priority for this winter is to FINALLY get a proper cage in the car. I'd also like to cut some weight from the car - Currently weighing in at 2380lbs and hoping to cut that down to around 2200lbs after the addition of the cage. Lastly, with a proper cage and a durable front hub the car will be ready for a power upgrade. 414WHP used to be a lot of power for a Miata... but that's practically common place these days! Still toying with what to do on the engine front, but plenty of options out there for LS engines.
I'm reasonably pleased with the laps times the car has put down so far, but I've restricted my use of the car due to the lack of a cage and the volatility we experienced with the OE front hubs. I'd like to get out to some new tracks and also knock a few seconds off laps times at Putnam and NCM. It would be really cool to break the 2:00 barrier at NCM! We'll see... Lots to do around the shop and only so many hours in a day. Hoping this thread and more involvement in this community will keep me motivated!
This is such a gorgeous build both on and off the track, a true testament to the skilled staff at Winning Formula and I can't wait to see this year's development and see how lap times progress with a cage in it!
11-28-2018, 10:36 AM
Winning Formula LS3 Mazda Miata...
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