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Can I put one seat stud extender set on top of another?
I have a '18 GS M7. I currently have Sparco QRT-R seat with seat rails from Vetteworks. The seat fits fine and the sits very low to the floor when using the supplied stud extenders (set of 4).
The problem I have is that the seat is too upright/forward-tilted. I'd like it a bit more leaned back, esp. when I'm wearing a helmet on the track. On the front uprights of the seat rails, I'm using the top most holes. On the rear uprights, using the top most hole is the only option. If I use any other lower hole, the seat bottom sits too low and rails don't sit flush on the stud extenders (thanks to the wiring harness plastic casing).
Generally, one leans the seat back by going higher on the front uprights (I'm already at the highest hole) or going lower on the rear (I'm at the lowest possible hole in my case, which turns out to be the top most one).
If the entire rails setup was higher, then I can go one hole lower on the rear! In terms of safety and sturdiness, can I put another stud extender kit over what I already have? Is that even possible?
I want to make sure I exhaust all options before I buy rails from another vendor.
I took a look at the side view of your seat on the Sparco web site. How are you using the Vetteworks seat mount? I had the original hardbar version of this mount that I used in my C5Z and C6Z with an aluminum seat. Here is a picture of how I had the seat fastened to the mount:
The Sparco side view is here:
Notice on mine how I have the upright set so it doesn't obstruct the belt and the belt doesn't rub against it when the belt is fastened. I am trying to figure out how to achieve the same thing with your mounting point while getting the seat lower in the bracket. I don't know how you currently have the brackets assembled but if they are like mine is there enough adjustment to lie the rear bracket on its side so the belt misses it and permits the seat to drop a little lower? Do you have the uprights to the inside of the floor mounts or to the outside, which way do you have your floor mounts put together with the L portion on the floor under the seat or outside of the seat?
I had the luxury of being able to drill the holes in the seat any place I wanted and to have multiple holes drilled if I wanted to change angles, having the seat mounting hole directly under the belt pass through makes it a little more of a challenge. You definitely need to keep the lap belt from rubbing on the vertical pieces of the seat mount as they will abrade it over time. How do you plan on mounting the lap belts in the car? To the Vetteworks mount? If so make sure you get a lap belt mount that permits the end of the lap belt to swivel. At an antique car online shopping site I found an old 60s/70s era Chrysler seat belt bolt that let me hard mount the belt to the Hardbar bracket but still let the lap belt swivel on the bolt end. The the longest part of the bolt was a smaller diameter while the part near the head was a larger diameter. That let me torque the bolt to the Hardbar bracket while I still had a half inch of bolt sticking out the lap belt hard end could be fitted to.
Bill
Last edited by Bill Dearborn; 03-08-2019 at 06:01 PM.
@Bill Dearborn , The L on the rails is towards the underside of the seat, NOT outside. My uprights are on the outside on the left side (and I don't remember about the right side of the drivers seat). I've mounted my lap belts using the bolt-in brackets from Schroth (just the bracket, didn't use the bolts), mounting them on the rear studs. So, the lap belt ends do swivel. Normally, there doesn't seem any rubbing, but based on the positioning of the center clamp, there could be a tiny bit of rubbing (see pics). I use the harness only for track days, about once a month at most. For street, I use the stock seat belts.
Even in this configuration, I'm as low as I can get on the rear uprights. If I go any lower, the seat bottom is too low and starts hitting the plastic casing for the wiring harness under the seat.The carpet is sufficiently trimmed and there is no interference with the carpet.
Bolt in brackets from Schroth for the lap belts.
Mounted the lap belts to the rear studs using the bolt-in brackets. The ends can swivel.
It doesn't seem to rub most of the time!
Very little overlap possible, a couple of mm at most.
I would absolutely not stack stud extenders. For my setup, I used the bolt-in B24 bracket on the lap belts mounted to the seat rails. This allowed all options for my Sparco Circuit II.
I would absolutely not stack stud extenders. For my setup, I used the bolt-in B24 bracket on the lap belts mounted to the seat rails. This allowed all options for my Sparco Circuit II.
I agree, there is no way that stacking the extenders is workable.
@Bill Dearborn , The L on the rails is towards the underside of the seat, NOT outside. My uprights are on the outside on the left side (and I don't remember about the right side of the drivers seat). I've mounted my lap belts using the bolt-in brackets from Schroth (just the bracket, didn't use the bolts), mounting them on the rear studs. So, the lap belt ends do swivel. Normally, there doesn't seem any rubbing, but based on the positioning of the center clamp, there could be a tiny bit of rubbing (see pics). I use the harness only for track days, about once a month at most. For street, I use the stock seat belts.
Even in this configuration, I'm as low as I can get on the rear uprights. If I go any lower, the seat bottom is too low and starts hitting the plastic casing for the wiring harness under the seat.The carpet is sufficiently trimmed and there is no interference with the carpet.
Bolt in brackets from Schroth for the lap belts.
It doesn't seem to rub most of the time!
I believe you should change the set up so it doesn't rub at all. This is something that should be discussed with somebody that has more credibility than I have. Joe Marko the owner of HMS Motorsports (the national distributor for Schroth) is a recognized track safety and restraint expert. His company provides the restraints used by most of the top NASCAR teams. He isn't always available but it wouldn't hurt to call the Mooresville, NC store and see if he could provide some advice. I have sat through a number of his safety presentations and he has constantly advised against having anything touching a harness that can or might abrade it. If he is willing to advise you it might be worthwhile to send him some pictures of your installation.
Very little overlap possible, a couple of mm at most. I am not quite sure of what I am looking at with this shot but the angle of the belt worries me. It may be just an optical illusion but it looks like it is bent laterally where it goes through the pass through (traveling straight from the mount to the pass through then making a turn to the right). When I read some of the studies that came out of the Dale Earnhardt incident one of the things they found is his lap belt had torn. He liked his seat very low in the race car and from the point where the belt was fastened to the cage to where it went through the seat and over his pelvis there was a kink which weakens the belt. That kink was due to the angle the belt had to take from the mount to his pelvis. If his seat had been higher it wouldn't have been a problem. In the wall impact that kink let the belt tear in two which was why his face contacted the steering wheel. Not sure that is what I am seeing in your picture but thought I would mention it so you can check for yourself.
As for getting the seat any lower on the rails it seems the only way to gain any space is to see if you can move the wiring harness and its enclosure. Is there enough slack to permit that movement?
Bill
Last edited by Bill Dearborn; 03-09-2019 at 03:13 PM.
Below is the picture of the wiring harness I'm talking about. This is NOT FROM MY CAR, I just looked these up on the forum. Ignore the heat/sound non-stock heat/sound shielding. The black plastic casing surrounding the wiring harness is stock.
Yes, mine are from Marrad. I didn’t have wiring obstructions on the floor of my 2017 Z06; the floor on both driver and passenger side was essentially flat.
In my '18 GS, it was flat with the carpet in place. The carpet foam is molded to be flush with wiring harness. Was it flat in your Z06 even after the carpet was trimmed?
I wouldn't stack the extenders! AMT makes great seat mounts and they are a forum sponsor. I'd call them and tell them what you're dealing with. Mark, the owner, will get it sorted out for you.
03-07-2019, 12:14 PM
Can I put one seat stud extender set on top of another?
