Miata Do A Seat Conversion (get it?)

In order to pass tech for my track day at Thunderhill I had to make a modification to the driver's seat in my MX-5. Track day companies stipulate that cars and drivers meet several safety requirements before being allowed on a racetrack. For convertibles, an approved roll bar is required. Additionally, the vehicle's occupants must not be taller than the roll bar and the top of the windshield frame while wearing helmets.

Taller than the roll bar. My head could hit the ground if my car flipped.

I didn't have time to get racing seats. Plus they're expensive. Some people recommend cutting out part of the seat cushion as a workaround, but I decided to replace it completely so that I can put it back the way it was if I ever want to.

It only takes 4 bolts to remove the seat. And I got to sweep out the carpet beneath the seat.

 The seat disassembles into two pieces. I removed the cushion from the seat pan and put in a thinner piece of foam that wrapped around the front of the pan. Then I used fabric adhesive to wrap the whole thing in some suede fabric that had been laying around. I punched some small holes in the suede and reused the seat's hog rings to secure the fabric to the pan.

I was concerned about rubbing against the metal pan, particularly during hard cornering, so I cut up some foam flip flops (black) and stuck them between the foam and the pan to add some cushion on the sides.

Reassembled seat and the original cushion.

It's not very pretty, but it works. (I swear I vacuumed out the car after I took this picture.)

After reassembling and reinstalling the seat I did the broom test (placing a broom across the windshield and roll bar above the driver's seat) to make sure I was sitting low enough, hence the helmet that's visible in the last picture. A few days later I was off to the races! (But not really. It was just a track day.)

With the new cushion I sit just low enough to pass tech.