Details

<<< Could you give us more details Steve. I have a Kirkey seat that I was planning to put in the car. How much did you cutout and what did you do for padding? >>>

Sure. The first seat I did this with was a fiberglass shell made by a company (no longer in business) Leslie. The shell used a vinyl cover with thin foam backing much like the current aluminum seats from Kirky and Ultrashield. This was in my '77 autocross X. I removed the seat tracks that were spot welded to the floor. This allowed the seat to sit flat on the floor and allow adequate headroom. I bolted the seat to the floor and rear bulkhead using a simple fabricated bracket.

When I built my '74 DSP X, an interpretation of the seat rule was that welded in seat tracks couldn't be removed so I had to work around them. I used the same fiberglass seat and set in on the tracks. I marked the location of the tracks on the bottom of the seat and cut the area between them out. I left several inches of the front of the seat bottom in place and cut all the way back to the transition to the sat back.

I bolted the seat to the floor by drilling holes through the center of the seat tracks and to the rear bulkhead with the same bracket I had used previously. After refitting the cover, you couldn't tell the seat didn't have a bottom. Sitting in the seat, my but fit right between the seat rails which acted like additional bolstering. It worked exceptionally well.

The final version was in my '80 DSP X. The Leslie fiberglass seat wasn't SFI legal so, while legal for autocross, wasn't legal for most track days. So I bought an Ultrashield aluminum seat like the one currently in my MR2.

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This is the MR2, not the X.

The nice thing about aluminum is it is easily formed where fiberglass isn't. For installation in the '80 X, I followed the same proceedure. Place seat on tracks, mark position of tracks on seat, cut seat bottom away, leaving about six inches from the leading edge in place for structure, all the way to the bottom of the seat back. This time I left an extra inch of material inboard of the seat rail marks.

I drilled and fitted the seat in the car, again bolting through the seat rails (a very sturdy mounting point). The inch of extra seat bottom material between the seat rails I then formed to blend with the floor. I did this by notching the seat bottom about an inch so that I had was was effectively tabs or flaps toward each side and the front. I then used a 2 lbs hammer to bend the flaps downward to meet the floor. This contoured the edges of the seat bottom to the floor of the car and removed the hard edges the fiberglass seat had. As before, once the cover was fitted you couldn't tell the seat didn't have a bottom.

This final version worked very well and made for a very comfortable bottom. Since you are now sitting on the actual floor of the car you get maximum headroom. I like to sit very low in the car anyway so this works out well for me. Also, I found I sat so low that I had to shim the steering wheel slightly lower for an ideal position. I also used a Momo Prototio steering wheel that was about 12.5" diameter. I had no clearance issues with the wheel or console.

This arrangement works very well for autocross however, I would warn you of a potential safty issue for track and/or highway use. Because you are sitting on the actual sheetmetal floor of the car, any impact to the floor there is transmitted right into your butt/back. I was always very carefull at track days to not take the FIA curbing too agressively. I figured that were I to jump the curbing and come down hard on the floor under my butt I could injure my back. Nor did I ever drive this car on the street.

In these pictures, if you look closely you can see how low I am sitting in the car. Note also that my helmet is completely under the targa bar.

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Steve
1x5