I've planned to replace my stock, ripped seats since I got my Monte, and a Kirkey 55 series seat is what I'm leaning towards. The only reason I haven't gotten one yet, is mounting concernes.



This is a picture of where the rear of the seat mounts. The front has a similar rib in the floor to where the seat mounts, but the seat doesn't bolt in at the front. It "slots" in, using hooked feet. I would need to drill through the front rib, in order to bolt the seat down on all four corners. How would drilling holes and bolting the seat down be done safely?

 

The rear of the seat usually fits under the Backrest portion of the seat so it will fit in a tab of some sort.
If the seat you are planning to install is not stock to the car you could get an (L) bracket at the hardware store and mount it to the floor with bolts and then drill into the portion that is up to use a fastener to hold it in place, or you may need to have a nut welded to the rear of the bracket.
If you have a U-Pull it type salvage yard nearby go to it and look at the Various cars and see how all that is mounted. I always use my phone to take a few photo's too.

 

Just spitballing some ideas - is it possible to remove the factory rails from the stock seats and find a way to attach the new seats to them instead?

 

A majority of race seat manufacturers recommend against using stock rails. I don't quite know the reason behind the recommendation, but I'd guess its due to safety concerns. I wanted to use side mounts, that attach to the sides of the seat, then the floor. Which is why I mentioned drilling new holes through those ribs in the floor.

 

Odd, youd figure stock parts would have far more stringent requirements than any aftermarket stuff.

As for drilling / bolting through the floor, I'd suggest looking for requirements for bolting cages in using backer plate metal to spread the load out. Youd want to do something similar drilling through the floor for a seat, especially in a spot which wasn't originally reinforced for that kind of load.

One other thing to keep in mind if you intend to run it at the drag strip- they can get picky about aftermarket seats. If you've got a picky track, they may require following the NHRA rules which I believe includes requiring a connection between the roll cage and seat back on aftermarket seats. Had a buddy with a GTO locally that they wouldn't let run due to an aftermarket seat (he had no cage to even bolt it to) although swapping it with a stock seat at home was enough to satisfy them.

 

It might not be about safety requirements, more so an extra point of failure in a wreck.

Yeah, I had looked at some nhra specs regarding back plate material, thickness, etc. The thing is, i don't know what set of class regulations to follow.

 

I just really dont see the difference between bolting a seat to an aftermarket universal slider + bracket vs bolting the seat to the factory combo piece in terms of number of connection points.. Not at all trying to argue, I'm sure theyve got good reasons for suggesting against it. Just always curious to understand things.


In terms of the rule book, what is the most stringent requirement you saw for backing plates for normal steel body cars?

In the absence of having the data to be able to calculate what is needed, I'd err on the side of caution assuming it's not something absurd. I'm just thinking the cost delta due to slightly greater L/W/T is going to be almost nothing due to how little actual material we're talking about for a backer plate. It wont add any appreciable weight and no one will see it anyways.

 

I couldn't find the seat mounting specifications I read a while back, but I do know the requirements for mounting a roll cage to the floor. That requirement is .125" steel plate.
Additionally, I looked up the seat mounting instructions straight from Kirkey. Link
Theres that "We DO NOT recommend the use of stock sliders and adjusters" comment I was talking about.
Those instructions say not to bolt seats to sheet metal. Would the two "ribs" the factory seats mount to be considered sheet metal, or frame?
Also, heres the side mounts I planning on using. Link
I'm slightly worried about the seat being too low with this setup though. I wonder if I could use the appropriate thickness square tube in order to elevate the seat if it does end up being too low for my liking.

 

The entire body of a unibody car is literally stamped sheet metal.

I'd imagine their intent is for body on frame cars where the body sheet metal is thinner / weaker than a unibody car. But TBH you dont really have a choice, theres no way you're going to install a frame just to put seats in. Attaching seats to the unibody sheet metal has to be an acceptable option as all OEMs do it and their seats aren't flying out in crash tests.

 

Okay, that makes sense. I ordered the seat, and will figure out where I'm going to need to drill the holes once I get the side mounts. I'll definitely use backing material on both the inside and outside.