Preface
This page was written to be a central point of information for everything related to the CU Boulder Racing Team #719 Ecotec Miata competing in the ChampCar Endurance Series. I’m going to try my best to cover every little detail I can remember about build decisions, costs, and what I would do differently if I could start from scratch.
This car gave us a lot of headaches but was a ton of fun to build and put together. I would even argue that it was one of the fastest Miatas in ChampCar throughout 2021 and 2022 – and definitely one of the lowest budget cars on the grid at any race.
The Death of 303
We never really planned on building a new car, let alone an ecotec swapped Miata, but we wanted a new challenge when our first Miata, a green NB labelled 303, overheated badly and lost all compression at a 24 Hours of LeMons race at our local High Plains Raceway. That was an interesting race – our other car at the time, the white, black, and gold 720 NA Miata, blew a diff and its transmission at the same time. On the other hand, 303 blew its motor. Only logical Lemons answer? Pull the transmission and diff from 303 and put it into 720 to take the chequered flag.
With basically a clean slate, and the start of the school year budget, we decided it would be a good time to give 303 the attention it deserved. In my three years with the team, it had only been raced twice. It was slow, the seat was uncomfortable, and the cage design was terrible, basically making half the windshield a blind spot.
Aside from the mechanical problems, we just were not very fast. Not compared to the other Miatas, and especially not compared to Max and Susan’s (who helped us a ton over the last couple of years) purple monster of a Miata named Scrappy, bearing its own ecotec swap.
Building a New Car
With how bad (at least we thought) of a chassis 303 was, we decided we would start fresh with a new shell. It took about a month to find a decently clean donor car for cheap. We purchased a black 2001 NB2 Miata with hideous 17″ rims, no engine, MegaSquirt DIYPNP2, torsen differential, and a “working” 6-speed transmission for $1300. While a low number for a Miata at the time, this was probably the most expensive individual item we purchased for the car when we first built it.
Suspension
Current Suspension Components:
- Springs: 700/325 Eibach
- Shocks: Penske
- Bumpstops: Mazda Comp
- Tophats: OEM
- Swaybars: OEM
- Bushings: Energy Suspension Poly Bushings
Like everything else associated with this car, we chose the cheapest option we could. A donated set of blown Bilstein coilovers off of an old Spec Miata car. I don’t actually know where they came from, other than “Shawn gave them to us” when the team purchased its first Miata in 2017. Since then, they were sitting underneath an old team member’s back porch. We paired the required Spec Miata Eibach springs with the 700 and 325 spring rates along with the Fat Cat Motorsports bump stop kit. It was by no means the ideal solution, but it was cheap and it worked.
For sway bars, we lucked out and bought a pair of the Eibach sway bars used in Spec Miata for stupid cheap from a Boulder local who had to move out of his shop and was getting out of Miata stuff. I think we paid $50 for the sway bars and endlinks. After a few races we ended up removing the Eibach sway bars and reinstalled the OEM bars and endlinks, giving us an extra 40 points that we could use towards aero and an aluminum radiator.
Control arm bushings were sourced from Amazon. I have no idea if they were even legit or a knock-off. But we purchased a set of “Energy Suspension” poly bushings for $220. Looking back we should have done some more research and looked into other options, as I always noticed a lot of noise from the bushings when moving the car on and off the lift in addition to a full corner getting “stuck” when off the ground.
Since the car was first built, it has been upgraded to the new Penske Spec Miata coilovers with new Eibach Springs and the Mazda Motorsports bump stops. This was all purchased from Miatacage.com along with the roll cage for a different car. I never drove the Penskes, but I’ve heard it is a night and day difference in ride quality and feedback compared to the Bilsteins we were running before. The car also bottomed out noticeable less, which was an issue we had often with the splitter hanging off the front.
Alignment
This is a tricky one to talk about. It feels like we have always had issues getting the car aligned nicely and to the specs we wanted. A lot of this was probably on us as we would rarely use the same alignment shop more than once as it was always a last minute thing. Going off of the Rugged Badger build post and suggestions from local Miata teams, we ran with a 1/2″ rake to our ride height. I don’t remember exactly but I believe it was originally 4.5″ in the front and 5″ in the rear from ground to crushed pinch weld.
Again a last minute solution, but we had our car aligned on the Friday morning of a Road America weekend at a small shop in Wisconsin that was about 20 minutes from the track. It was one of those, “leave it to me and I’ll get you sorted” situations. But honestly, they did a great job, and we kept that alignment for a few races until we bent a tie rod and had to redo it. We have not been able to find anything that is as fast and as comfortable to drive.
The car was always on stock control arms with OEM style lower ball joints. I’m pretty sure something was bent at some point as we could never get equal amounts of camber on the front of the car. In late 2022 the car was upgraded with extended lower ball joints in an attempt to increase the range of camber possible.
Favourite Alignment Specs:
- Ride Height: 4.5″ front, 5″ rear (not confirmed)
- Camber: -2.8 degrees front, -3 degrees rear
- Caster: 6 degrees
- Front Toe: 1/16″ toe out
- Rear Toe: 5/64″ toe out
These alignment specs are by no means a recommendation, they are just what we have liked best so far without much testing. We tried a few other alignments but never liked anything as much as we did that alignment from Wisconsin.
Wheels, Tires & Hubs
- Tires: 225/45r15 Maxxis VR-1
- Wheels: 15×9 Advanti Storm S1 or 15×9 TRMotorsport C3M wheels
- Wheel Bearings: O’Reilly branded OEM hubs, now Mazda Motorsports hubs
Tires
Early on in the team’s history our choice of tire came entirely down to how much money we had left to spend. Often times, it would be a two or three race old set of 400 treadwear “performance” summer tire that we found on clearance or used on the local Lemons Facebook group. Starting at Sebring in 2019, we used Maxxis VR-1s due to the discount provided by ChampCar. We’ve stuck with the tire since. They’re affordable, seem decently quick, and wear nicely. We have had some issues with flat-spotting but every occasion was more down to driver experience levels rather than the tire itself.
Due to shipping delays from a winter storm, we ran a set of Falken tires at Harris Hill. They seemed slightly quicker (not much), but felt a lot less consistent and struggled to last 8 hours on track. We also had two go flat…
Wheels
Like most decisions we made with this car, wheel choice came down to price. When we originally purchased parts for this project (more to come later), a set of 15×9 TRMotorsports C3M wheels were included with the bundle. We needed a second set of wheels for the car so I found a matching pair for sale in Orlando, FL. I sent the seller a deposit and we collected them a few weeks later before the annual ChampCar race at Daytona. We paid $300 for the second set of wheels.
Bearings
We have always used whatever hubs and bearings the local O’Reilly or Autozone had due to the low costs. Before building the Ecotec we never had any issues with bearing longevity, and could usually go two or three races on a set. That was not the case with this car, the added power meant we were going through front hubs and bearings a lot quicker. We would replace them before every race and always bring at least one set of spares.
We had a hub fail at a Lemons race at High Plains. It was preventable as a team member had said it was good enough for the day. Should’ve changed it… Luckily we had no damage aside from the bearing as the wheel stayed attached. We also came really close to losing the wheel at a test day before Daytona when an ABS style hub (from Oreilly) cracked almost entirely around which could have caused a lot of damage.
Leading up to the team’s race at AMP in 2022, they upgraded to the Mazda Motorsports front hubs – purchased from Flyin’ Miata. I will have to update this post in the future with how they compare to OEM hubs.