Seat Considerations
Racing seats are another one of those things where there are a lot of things to think about. Fortunately, if you stick with a major name, seats are all pretty well built, and you can come down to comfort as one of your major deciding factors.
Here are a few things you'll want to decide on:
- fixed 'bucket' versus reclinable
- tube-frame versus fiberglass shell
- allowance for 5th belt or not
- side mounts versus bottom mounts
First you have to decide if you want your seat to be fixed or not. I think we'd all prefer to have a reclinable seat, but the issue becomes weight. Fixed seats like the OMP RS can weigh as little as 15lbs and not sacrifice strength, whereas the reclining mechanism makes nonfixed seats much heavier - 25-40 pounds.
After that's decided, if you go with a fixed back seat, you'll have to decide if you want to put up with a tube-frame seat (which are generally cheaper) like the Momo t-frame or Corbeau Forza, or if you want a full fiberglass, aluminum (or if you're rich, carbon-fiber) shelled seat. Seats are very much a personal preference, but I found tube-frame seats highly uncomfortable.
You'll also have to decide if you want to run a 5-point harness or not. The 5th hole allowance is not found on all seats, so you'll have to make sure the seat you like has this. Lower priced Sparcos and some Corbeaus tend not to have the sub-strap hole, but you should be able to find a seat that fits your needs here.
The last note is pretty trivial. Some seats are made to mount on bottom, some on the side so that they can sit lower in the car. Some will mount either way.
Installation Notes
Update 2003.01.15
[I installed a Corbeau Forza on the passenger side, just to get a bit more weight off, and enable the 5th point to be installed. I didn't want to have to re-make these brackets, so I bought Corbeau's brackets. In hindsight, I wish I hadn't. The put the seat quite high up, and too far outboard. However, the adjustability is nice. Further, the brackets did not fit right, and I had to re-drill the holes for the mounting hardware. However, the seat fulfils its one goal: to be light.]
Update 2003.01.06
[I decided to re-do the brackets as I initially did in this VFAQ. I had a bit of trouble with the brackets coming loose and separating on me. I replaced the lower "open" metal piece with another tube of 1x1 square steel, and the (now 2) pieces of square steel rest atop a 2x1/8" piece of barstock, with holes cut for the exact spot that they fit into the stock mounting holes. See the new pictures below. The basic problems and such of DSM seat installation still exist, so I decided to leave the rest of this text.]
I can't emphasize this enough - seats are a very personal choice. As such, you'll have to find a shop around you that carries a pretty good stock, and go plant your ass in a bunch of them. I walked out with a completely different seat in mind than when I walked in.
So, the seat I ended up going with was an OMP RS. OMP isn't as well known since they don't advertise much, but they make awesome, high quality race parts. The RS is a 15ish lb side-mount fixed seat made of fiberglass. It has an allowance for the sub-belt passthrough, and fit me like a glove. I'm 5'7 and about 170#.
Installation was a bitch.
It also ended up more costly than I had expected. The Sparco aluminum sidemounts were the lion's share of that cost, but for my side-mounted seat, they were a lifesaver. The other costs are about what you should expect - $100 or so on top of the cost of your seat to mount it.
There are two difficulties when installing a seat in DSM's. First is the fact that there isn't squat for headroom, even when you're a munchkin like me. The other problem is that the floorboard isn't flat due to the bump of the driveshaft tunnel. The brackets you have to make have to be quite wonky just to get the seat mounted correctly.
If you examine the stock seat, you will notice that the seat is offset about 5" inboard on its brackets. The brackets bolt to the floorboard, but the inboard-most edge of the seat is about 5" over that bracket, while the outboard bracket more-or-less sits over the left edge of the seat. So, we have to duplicate this so we can get the seat as low as possible, and not have the steering wheel be offset to the right. You will end up mounting the seat as far to the right as you possibly can.
The first thing to do is to start on the base. The Sparco "Universal" (*snort*) kit that I have had two square pieces of steel that turned out to be *just* long enough to run front-to-back the length of the stock mounting points. A third piece with curved ends I could turn over, and it ended up standing just high enough to make the four mounting points more or less coplanar. (fig 1, fig 2).
(these are the parts I substituted with 1x1 steel in brackets 2.0 ;-)One side of the two square pieces was slotted along the length, so I was able to install the nuts (front) and bolts (rear) into the floorboard, and then slide the brackets over them. In the future, this may enable me to gain back some fore/aft adjustment. (fig 3)
After test-fitting the seat, here is when I noticed that you must offset it quite far to the inboard side of the car to have the seat be centered on the steering wheel. That is easy enough to accomplish, but the second problem is that the angle of the driveshaft tunnel prevented me from doing so on my side-mounted seat (perhaps it would be less problematic on bottom mount seats? I don't know). So, I had to build my bracket higher to allow myself to move the seat further inboard.
To do this, I used a piece of 1" square steel on top of my original square pieces. (figs 4,5,6)
From here, I needed a flat surface on which to mount the bottom of the Sparco aluminum side brackets. For this, I used some 2x1/8" "L" steel, bolted to the top of my 1" square steel. Ultimately I'll have all these welded into one piece, but for now, I used my 14mm bolts. On the driver's side, I was able to mount the L right on top, as indicated in figs 7 and 8.
For the inboard bracket, since we require the offset on this side, I mounted the L to the outside (inboard) side of that bracket. If you do this, don't forget to offset the L upward the width of your steel so it is the same height as your driver's side. IN my case it was 1/8".
That's about as much specific help as I can offer. From here it's a lot of phenagling and tweaking to get the seat exactly where you want it to be. As of this writing, I've taken about 15 hours getting these brackets made and tweaked so the seat is in just the right spot. I've got a few positions now for me, and for drivers that would be a bit taller than me. I think now I just need to tweak it so the seat leans forward just a bit more, which, fortunately, I can do with the Sparco brackets that I bought.
Take a gander at the rest of the final installed photos (figs 9-13) - they provide a bit of illustration to the things I mentioned above.
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