Getting the Super Touring 6 Miata down another 130 pounds is no simple task. In part 1, I laid out a plan of attack that I started at the most recent Nashville Superspeedway event. I brought my scales to document the weights, and although I may have looked like a maniac with a Sawzall in the paddock, the result so far is 55 pounds and counting. Here is the progress so far.
The Easy Items
Even in its current state, there are still a few ‘easy’ pounds to remove from the racecar. Starting with a weight of 1977 without a driver, I removed the wiper and wiper motor, along with the hardtop window gaskets and mounts. This was a quick and easy 7 pounds.
Of course, I kept the wiper motor assembly to go back in on a rainy day.
Removing Side-View Mirrors and Cutting the Doors
The following two areas would net 12 more pounds. First, the side view mirrors are pointless in the Miata and worth a couple of pounds each. I have roll cage-mounted side view mirrors that do a much better job of letting me see my blind spots. So out they go.
I have very high and beefy door bars on the cage, so I removed the top support from the driver’s side. From the passenger’s side, I removed the quarter window, support, and top support. All it took was a quick session with the Sawzall.
Seat Belt Mounts and Trunk Firewall
Cutting the seatbelt mounts and the trunk firewall removed an additional 14 pounds. Once again, the Sawzall came out, as did my full complement of safety gear: a respirator and face shield.
Modifying Rear Bumper
I cut the lower edge of the rear bumper skin to improve aerodynamics. It opens at the bottom and acts as an air scoop, but in the wrong direction. I didn’t realize before starting, though, that mostly gutting the bumper would save significant weight—almost 11 pounds.
One other note about modifying the rear bumper: This is another area in which I can be more aggressive with material removal, especially around the wheel wells. However, as this car had to pass tech and race the following day, I wanted to ensure I didn’t go too far. I suspect another 5-10 lbs from the surrounding areas, though.
Hardtop Rear Window
The rear glass in the hardtop weighs another 11 lbs, bringing the grand total to 55 lbs. This is a relatively easy removal. Someone in the paddock claimed the glass was worth $500, so after removing the nuts from the inside, I used a heat gun and gently pried the glass off. I also managed to get it home in one piece.
There is a conflicting opinion on how the rear glass affects performance. I will discuss that next time. (Link incoming.) Occam’s Racer has a good article on the subject, but it is geared towards cars running wings and splitters. When dealing solely with mechanical grip, the story is a bit different.
More Weight Reduction Opportunites
That is it for this installment, but it is not the end of this process. I am trying to get as much weight (at least another 50 lbs) off of the Super Touring 6 Miata as inexpensive as possible. There are at least 20 more lbs through creative trimming, and I was shocked that the rear trunk is 30 lbs. I plan to shave another 50 off the car by focusing on these areas. And with around 20 lbs in driver adjustment, the ST6 Miata will be at the pointy end of its capability in the power-to-weight department.
