Would it be legal to mount a driver's seat using two bolts from the floorboard and then the seatback tie to the roll cage? Just wondering if I should go ahead and make something to tie the front of the seat into the floor as well. Just wondering @ 1am after a long morning/day/night under a car.

 

Here is what the rulebook says:

The driver's seat of any car in competition must be constructed, braced, mounted, and upholstered to provide full back and shoulder support. The driver's seat must be supported on the bottom and back by the frame or crossmember. Except as noted in SFI Specifications, seats must be bolted with four bolts (and nuts and washers) on the bottom and one bolt in the rear into the crossbar; all bolts must go into frame of crossbraces.

In my race car I'm using a Poly seat from Jeg's. What I did was build a bracket that I attached the seat to. I then bolted the bracket to the floor using the factory seat studs. Then I fabricated a brace out of 1" square tubing that attached to the back of the seat and welded it that the crossbar.

 

Thank you very much. Looks like I have to do a little redesigning Monday. I hadn't tied into the front bolts and didn't plan on it unless I had to.

 

I made my frame from some thin aluminum channel. Since it's not bolted onto the factory studs I needed some way of securing it to the floor. It just happens that my SFC runs right under the seat. I welded some angle iron on both sides of the SFC in which to bolt the seat frame to. That falls into the rulebook as being bolted to the frame since the angle iron is welded to the SFC and the SFC are welded to the car. As mentioned above, if you can use the factory mounts, that will be acceptable. My seat sits back farther so the factory mounts wouldn't do.

You can't just drill holes through the sheetmetal floor and use fender washers to keep the seat from ripping off the floor in case of an accident.

 

I'm using the factory rear bolts on mine. I'm 6'4 so I enjoy the extra leg room. If I tie in using the factory bolts (which are mounted on a reinforced channel from the factory), that should be legal, correct?
Your subframe idea is really good, except that 3rd gen subframes run a lot closer to the center of the car than 4th gen. My SFC are out by the door sill.

I think if I fasten the seat to the rear bolts and make two aluminum brackets that bolt under the front lip of the seat and tie into the front bolts (along w/ the tie to the rollbar), I should be fine.

 

My SFC are custom made. They can have been positioned anywhere. Many of the aftermarkt ones, even third gens, run along the rocker panels which wouldn't work for me. Headers were in the way so I made my own.

Mounting to the factory bolts is legal since they're already reinforced.

 

Cool. Thanks a lot.