Submarine Belt Mounting

[Rambhagwan]

Hey all. I've looked and looked for an answer to this but haven't been able to find it anywhere. Then I looked some more and still got nothing.

I'm doing a Cobra racing seat + 5 point harness install for both driver and passenger sides. The shoulder belts have wrapped around where they're supposed to wrap around no problem. For the lap belts, I bought eye bolts and backing plates. To my pleasant surprise, one eye bolt per seat just fit right into the stock seatbelt mount. For the other side, I drilled a hole into the transmission tunnel and with some large washers and a nut, I was in business.

Then I got to the submarine belt. I thought it would be as straightforward as the other belts, but this tiny little belt is slowly, but surely, killing me.

Right under the central point in the seat where the hole for the submarine belt should go (According to Simpson's specifications), there is a large chassis frame structure underneath the floor. This makes it difficult, if not impossible, to drill a hole in that area and place a backing plate where the eye bolt would come out from the bottom. It would involve cutting a significant portion of that frame structure. I can take a picture if you don't know what I'm referring to, but you should be able to easily see it right next to the set of 6 or so lines that run to the back of the car.

I'm thinking to myself...this is a very commonly tracked car and, surely, there should be thread upon thread of how people have solved this inherent problem with the sub belt mounting location. But in my searches, I've found that people either use the Takata/Schroth 4-point belt with ASM or don't discuss the issue of the sub belt mounting at all. Since the chassis of my car shouldn't be any different than any of yours, I'm hoping someone can give me a simple, "No, you idiot, just do this" and then I give you a high-five and go have fun at Road Atlanta.


I've since come up with some alternate options should this drilling thing remain an impossibility. One was to build some sort of cross beam that goes from the front left seat mounting point to the rear right seat mounting point. Then just drill through and attach the eye bolt there.

Another is to buy something like this https://www.harrisonmotorsports.com/...ent-plate.html and weld (jb weld maybe?) it to the right location on the floor. I could then cut the eye bolt shorter and screw it in there and not have to worry about drilling through the floor.

Either way, I've been losing hair for this and I'm quickly running out. So please, O tracking Gods of ft86club, please shine some light on this issue for me.

[TRAKRAVN]

Why not try a 6 point harness? The two sub straps give more room for the boys and can mount on either side of the crossmember.

[Rambhagwan]

Yes absolutely a good idea. Unfortunately I thought of that only after running into the problem of not being able to mount the 5 point :/ I ordered the 5 points quite some time ago, so returning isn't an option anymore. And 5 points are very common so I figured it would be easy enough to install


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[Code Monkey]

Sell the 5-point and buy a 6-point, totally worth it.

[mav1178]

Not the safest idea but at least this is an option?

http://www.ft86club.com/forums/showthread.php?p=2893396

[redlined600]

Originally Posted by Rambhagwan

.

Another is to buy something like this https://www.harrisonmotorsports.com/...ent-plate.html and weld (jb weld maybe?) it to the right location on the floor. I could then cut the eye bolt shorter and screw it in there and not have to worry about drilling through the floor.

Absolutely no jb weld. Not to pry but what do you have the shoulder straps mounted to?

Imo, sell 5pt, buy 6pt. It's better in every way. Bottom end certified 6pts start at like $150.

[Rambhagwan]

The soulder straps are mounted to a gspeed roll bar.

I see so it seems that most people get around the issue of the cross member by using a 6 point. Alright I'll hold off a few days to see if any 5 pointers see this post and have some fix. If not then perhaps thatll be the way to go.

Yeah the JB weld was more out of curiosity since it has a good PSI rating (~4000 lbs?) and I think I can get some good coverage area on the floor. Thought it could hold quite well if applied properly


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[zdr93523]

I'm not sure what the issue is. You should be able to drill a hole (or 2 preferably for a 6 point) and install the eyelet and backing plate. If you're an inch or so forward or back to avoid a braced or thicker section of the floor, you won't have any problems. Just make sure your mounting hole(s) is directly below or behind the hole in the seat, not forward of it.

[Rambhagwan]

Yup that's exactly what I thought but the thick underbody frame part extends from the front of the car to the rear. So moving forward or backward still puts it right on top of it.

Perhaps someone who has installed a 5 point can be so kind to post a picture or two of their install. Like I originally said, I would love for the problem to be something stupid I just overlooked


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[bcj]

Glues and tapes only ever perform up to the load specs in tension. Straight up and down.
If you apply shear loading - across the plate - the load to break the stickum is significantly less.

There was a commercial for some glue a few years ago that had a guy hanging from a hard hat on a lift of some sort.
A straight lift across the join section is fine. Give him a kick in the nads and he'd go flying.

[SpartaEvolution]

Could you drill and install the bolts on either side of the frame rail, then triangulate the belt with a locking carabiner or something? Probably not strictly legal?