Mounting Race Seats
 

Folks, I need suggestions on mounting race seats. I expected this would be a problem but until a week ago I didn't have seats to actually try to fit. I played around a bit this weekend and am looking for suggestions on lowering them. I've got one Sparco Evo seat and one Sparco QRT-R. I intended for the QRT-R to be the driver's seat. Dimensionally they are similar. Both seats, when mounted to Planted seat bases using standard sliders with Sparco side brackets, sit too tall, as expected.

I've got a few options as I see it, but am looking for other suggestions.

1) Ditch the sliders. I'd like to keep them if possible, since one of the people who will drive this car is significantly shorter of leg than I am.
2) Notch the seat - currently the limiting factor to lowering the seat on the side mounts is that the edge of the lower portion of the seat contacts the slider. If I remove some material from the seat, I could lower it maybe 20mm.
3) Cut, re-shape and weld the rail that spans the door sill and the trans tunnel. This is the main limiting factor to lowering the bracket in the chassis

What have you guys done to get your seats lower?

When I installed a Corbeau FX1 Pro I used sliders and custom fabbed a bracket that tied into the OE mounting holes.
I also did a bit of creative fine adjustment with a hammer and a pipe to make some room in the trans/sill brace for the sliders.

The rear OEM mount locations are raised a bit off the floor. My bracket steps down from there to be flush with the floor and that's where the sliders attach in the rear.
The front attachment points end up being elevated a few inches relative to the rear but that sort of makes sense since the trend in human height is that longer legs are generally correlated with longer torsos. This also gives a few extra degrees of angle to the back for extra comfort driving to/from events (though I expect this won't apply to you).

For reference, I'm just shy of 69" tall with a 33" inseam. I pretty much lucked into it being the perfect height for me at the best distance from the pedal.

Thanks. That's kind of what I suspected. I don't suppose you have pictures of what you did?

Nothing handy. I can probably get some tomorrow.

No big deal.

So I pulled back the carpet and performed some surgery on the driver's side part of the transverse brace under the seat and that let me drop the front of the seat mount an inch after re-drilling the holes on the bracket. I cut the rear mounts off of the bracket and I'll just modify those to be lower and re-mount them. I may end up running the Evo seat on the driver's side (with a slider) and use the QRT-R on the passenger's side (no slider) since the QRT-R is a little bit taller of a seat.

If this doesn't get me enough I may need to cut out the rear floor mounts and lower them. Really don't want to do that as it's pretty invasive surgery.

Thanks for the tips. I have so much else to do with this car I was really hoping seats would just be a bolt in and go kind of thing. Annoying.

JV

i've seen serious folks just go ahead and cut out the OEM seat mounting structures, both front and rear, entirely. Either cut the spot welds if you're patient or break out an angle grinder and cut away. This let's you get stupid mounts of head room (seen 6'5" guys that you can barely see their heads through the side window). Search "ARCA time attack build", he's got some good pictures. You'll need to run back-up plates under the floor at minimum; the better way is to weld in some new low profile reinforcement plates.

I literally had the spot weld cutting bit in my drill and was plugging in the drill when I took a step back and thought, "I don't have time for this." I realized that if I really had to, I could just run the stock seats for a period of time and be fine while I finish the other stuff on the car that needs to get done like aero, engine management tuning, alignment, bump steer and the thousand other little things that need to get done.

An effective way of lowering the seat while keeping sliders is to get Buddy Club Super Low seat rails:

https://www.soloperformance.com/Budd...-_p_11494.html

I've got these and it puts me about as low as the stock seat with a Corbeau FX1 Pro with the bottom cushion, and removing the cushion gets me lower still.
It took forever to get them, since I think it needs to be special ordered from Japan. I needed to bend the side brackets to match the taper of the seat, which was a minor annoyance. I guess they're not particularly light either, if that matters to you.

I tried to order those twice and twice my order was cancelled for "no stock." I gave up.

I ended up getting the seat low enough. I cut the rear mounts off of the Planted seat base, reshaped them and re-welded them to the base so it dropped the rear an inch to match the inch I dropped it in front by re-drilling the holes. I was also able to modify the side mounts for the seats and drill new holes in the rear to lower the rear another inch plus a bit. I can comfortably fit with a helmet on at this point so I'm good.

That's too bad about the Buddy Club seat rails. I'll keep your solution in mind in case I want to put a passenger seat in eventually.

I finally just ended up making custom brackets. None of the aftermarket ones work if you are more than about 5'6"

since I'm the only driver I set them up for me and didn't add a slider 🙂

Planted also makes a real low-profile race seat mount for the RX-8. I have Wedge Engineering mounts in mine. They were on the car when I bought it.

I've had a bitch of a time mounting a passenger seat in my car. I think what I'm likely to do in the future, if I get around to it, is welding in mounting points behind the side impact beam, so the seat is sitting in the foot well for the rear seat. Right now my car has a shelf there for a coolshirt box.

this probably wont help you much but this is how my car is done. im 5'4" so the seat is very forward. had extra set of holes on the bracket to move the seat 2" back and 1" lower if someone else taller needs to drive my car.

https://cimg4.ibsrv.net/gimg/www.rx8...747b85cdcd.jpg

https://cimg5.ibsrv.net/gimg/www.rx8...4402e33a92.jpg

Those mounts aren't tied in to your cage, though? I mean, my seats are bolted to the floor, too. But if I go the custom route you have, I expect I'll tie it into the cage somehow.

not tied to the cage but still stronger than just a bracket with 4 bolts with stock mount.

Looks like a good way to do it, but yeah, doesn't work for my class rules.

Modifying the planted mount was easy enough and seems like it's plenty low enough for me. I've got enough range with the sliders that my ~ 5'3" co-driver should be able to drive the car as well.

Understand that I don't know what the hell I'm talking about. I've never built a cage myself. My experience includes having a roll bar welded into my last RX-8, and buying another that already had a very skookum cage built into it already.

When I refer to 'tying the seat mount into the cage,' I mean adding structural elements that extend to the cage itself. That may be totally unnecessary. My race car just shows signs of the seat having torn out of the floor in an accident and having been subsequently repaired.

https://cimg8.ibsrv.net/gimg/www.rx8...10d0e7f3b1.jpg
I'll see if I can find a better picture of after the install too. I don't take many pictures of the car.

https://cimg1.ibsrv.net/gimg/www.rx8...18e73d9b2a.jpg

Old pic, interior is all gone, wheel changed out and door panels gone too. But with the stock interior these fit and allowed me to slide a fair amount. Car will eventually have a full cage, not a roll bar. To my understanding this is enough for what I need for safety minus the halo around the head area for the NASA ST class.

I know its too late for you but I ordered a Driver's-Side Buddy Club slider from a place called Evasive Motorsports and they had it in stock. Got here in about a week. Now I just need to find a seat that I like and hope it'll put me a bit lower. I'm tired of my helmet up against the headliner.

https://www.evasivemotorsports.com/s...-8-04-11-left/

Good stuff, thanks for posting.

Not to disappoint at all but the Buddy Club rails aren't really that low, at least with my REV it sat higher than stock because I couldn't use the lowest holes in the buddy club rail. I'm hard mounting with Planted rails now just so I can get that low.

Do you have any pictures of how you modified the mount and/or the front crossmember? I'm looking to do something similar, I just got a planted mount in the mail and it's not low enough for me.

I too had that same issue. that's why I went the route above by removing the entire mounting system and welding in new floor mounts. Then rails directly to the floor in a way. Planted was not low enough in any way.. waste a money for my seat combination.