When I first started racing a friend told me to go where the competition is. Simple advice really but as someone that likes to build it was definitely something I needed to hear. That is exactly what I did when I entered 944 spec with NASA Midsouth. A class with large fields at home as well in the Southeast and Great Lakes regions.
I’ve enjoyed several successful seasons in 944 spec and my skillset has grown immensely as a result. Although I will continue to support and race the pink #901, it is also time to expand my opportunities.
Spec MX-5 or Spec 46
(I considered a lot of factors during this decision and may expand on that at a later date.)
I initially started this journey looking to enter spec 46 as both 944 spec and spec e30 are slowly feeding into it. However, after racing a car that is almost older than myself, availability is high on my list and I quickly found the manual transmission 330ci that spec 46 is based off surprisingly hard to come by. And due to the likelihood of having to start with an automatic car, I shifted my focus to spec MX-5. To summarize, at this point in my career I am focused on the pursuit of speed and not parts.
Immediately I found an abundance of quality donor cars for spec MX-5. It is a quickly growing spec class with nationwide racing and crossover potential with both NASA and the SCCA. And as I dug into the rule book it became apparent I was going this route.
Donor and Baseline
Finding a donor was ridiculously easy using Facebook marketplace and craigslist. I’m gonna sound like a broken record about this but I immediately found several choice candidates very close to home.
The choice donor car for spec MX-5 is a six-speed chassis with limited slip. I settled on a red 2006 grand touring model properly equipped with 100k miles. I picked this one up for 7k which is on the high side for a donor but it was too nice to pass up and honestly probably too nice to convert. The only thing I compromised on with this chassis is the suspension. Ideally I would start with a completely unmodified car but this one had seen an autocross or two and the owner installed a Flyin’ Miata stage 1 kit that I am not too impressed with. Given that it could be 10 plus years old though, it most likely is well passed it’s service life and leaves the car feeling twitchy.
![](https://i0.wp.com/www.driftopia.com/blog/wp-content/uploads/2020/10/IMG_20200820_121615_797-scaled.jpg?resize=720%2C601&ssl=1)
Starting with a car that has been very well maintained has been great. I’ve been able to enjoy it around town and I dare say I enjoy this car more than the Lotus on public roads. The extra creature comforts are nice but mainly I don’t feel like I have a target on my back in the MX-5.
Now to the baselines. Before touching or changing the car I documented the weight of the car fully loaded as well as compression testing the engine. Then I wanted to take the car somewhere I could explore it’s limit.
Weight
Weight with a full tank of gas is 2505lbs. Minimum race weight is 2500 lbs which means I need to remove a few hundred pounds from the car as the roll cage and my own weight will add a bit back. I like to set my racecars at minimum weight with 2 gallons in the tank to account for scale fluctuations, avoid any fuel starve issues and account for miscellaneous weight changes.
For consistency purposes, I will weigh the car on a full tank during the weight removal phase.
![The NC MX-5 on longacre scales to calculate the overall weight of the car without driver and a full tank of gas.](https://i0.wp.com/www.driftopia.com/blog/wp-content/uploads/2020/10/20200908_094405-scaled.jpg?resize=720%2C405&ssl=1)
![Closeup image of the weights at each corner on the longacre scale display.](https://i0.wp.com/www.driftopia.com/blog/wp-content/uploads/2020/10/20200908_094342-scaled.jpg?resize=720%2C405&ssl=1)
Compression
Just like the rest of the car the motor is healthy. Yielding a 210 psi average across all four cylinders with only a few psi variance. Since 180psi appears to be the rebuild zone on these motors, I will be able to do an ‘everything but’ approach to the build. Freshening up the motor and adding the spec cylinder head last. Allowing me to test the car in a progressive manner.
![](https://i0.wp.com/www.driftopia.com/blog/wp-content/uploads/2020/10/20201002_141259-scaled-e1602517140648-1024x905.jpg?resize=720%2C636&ssl=1)
Track Testing
It’s been years since I’ve driven what is effectively a street car on the track and I immediately discovered I’m a pansy without a full safety complement. However, I was able to push through and give the car a thorough ‘testing’ of sorts during a local track day with NASA Midsouth.
Testing consisted of 4 sessions. Here is a summary:
Session 1:
Traction control (TC) was intentionally left on. It’s pretty easy to activate during street driving and I wanted to see what it would do on the track. It is aggressive and activates on any turn with tight transitions. Also, I quickly lost confidence in the brakes and pulled off the track after lap 2. I knew this would be an issue but didn’t think it would happen almost immediately.
Session 2:
Brake fluid and brakes were swapped with race fluid and a set of Hawk DTC 60’s. These aren’t the spec MX-5 pads but I have access to Hawk pads through 944 spec contingency programs. The MX-5 brakes quite different from the 944 and my initial impression is that the 60’s are probably too aggressive albeit fade proof. With the brakes in order session 2 was run with the TC off.
I started feeling the car out during this session and building pace. Soon discovering the limit is absurdly low with the aftermarket suspension and old tires. The chassis had a tendency to snap to the right. Nothing uncontrollable but the chassis did not have the planted feel I expect from an MX-5.
Session 3:
More of the same except I forgot to turn the TC off. Thought this was funny in the video. Nothing looks out of place but my ass could feel it. Trying to balance a car with the throttle and activating TC simply doesn’t work. I quickly turned it off on the straight and got back to driving.
I realized the ‘birds’ chirping every time I passed the wall section at turn 7 was actually the tires screaming in protest and not in fact birds.
Session 4:
Full lap for reference. This car isn’t going to go any faster in it’s current state.
Audio is pretty much useless due to the wind noise at speed.