Can the sub belts be properly installed in an E30?

[Earendil]

The pieces for my Roll Bar + Harness + Seats are coming together, and I'm noticing a potential problem, there is not room to properly mount the submarine belts with my setup.

The documentation (page 16) states that the submarine belts for a 6 point harness should be mounted between the points:
directly below the seat hole
rear of the seat hole, with the angle not exceeding 20 degrees.

My issue is that the OMP belts (804s) I have require 3.5 inches of room given the default tiedown mechanisms, but the distance between the E30 floor pan and the Sparco Pro 2000 is only 2.5 inches.









I figure my options are either:

1. Mount it about 8-12 inches behind the seat hole. Way steeper angle on the belts, but mounting is easy enough.
2. Raise the seat - to keep a proper sitting angle with the current side mounted brackets, I don't think I can buy myself an entire inch.
3. Get a different seat adapting bracket, one that sits up off the floor further - will be a little bit of a crap shoot, since the non-branded bracket I have came with the seat. I also already feel like I'm at the same height I was with the stock seats.

How does everyone else solve this? Is it not a problem for the majority of seat/mount/harness combinations, or is it a problem for most and there is an acceptable work-around?

[Axxe]

We mounted ours further back on the floor so the latch would angle nicely in our ChumpCar, and Tech blessed it. Keep in mind that the opening in the seat will dictate the angle. If you want something lower profile you can swap your clip in end for a bolt in.

[Earendil]

Thanks for the reply, Axxe!

I keep reading more and more, and it seems that most people don't do what Scroth suggests, and will mount them pretty far back, but still under the seat.

In my case with the Pro 2000, the hole for the sub bets puts the belts going through the hole perpendicular to the seat bottom. That means that any further back than where gravity would have them land is going to put an angle on it. Due to where the seat bracket is, I have to go back from the hole about 10 inches, which some really back-of-the-napkin-math looks like approximately a 70 degree angle. I have to think this hardly matters though, as any angle at the seat hole has no bearing on how the belts sit on my legs and groin.

I put both lap belts under the car 10 inches back and pulled them taught to see what the routing around the seat adapter should be. One is under (bad) and one is over the top, which looks okay. That sort of shows you the 70 degree angle I'm working with. Picture is taken from the floor, looking rear.


(doesn't everyone install harnesses with a hammer?)

Axxe, is that more extreme than what you have?

[GillesBigCowboy]

I wouldn't want the belt rubbing and significantly deflected by the silver metal seat adapter cross brace thingy so much. Our two racecar seat mounts don't have anything like that going across the path of the sub belts.

[FredK]

I wouldn't want the belt rubbing and significantly deflected by the silver metal seat adapter cross brace thingy so much. Our two racecar seat mounts don't have anything like that going across the path of the sub belts.

Me neither.

One solution for low profile applications is to swap the sub strap to bolt-in hardware rather than the snap/eyelet style you have right now.

[Earendil]

I wouldn't want the belt rubbing and significantly deflected by the silver metal seat adapter cross brace thingy so much. Our two racecar seat mounts don't have anything like that going across the path of the sub belts.

when you say "significantly" deflected, do you mean the bottom belt (which I agree is terrible) or the top belt? The top one is sort of hard to see, especially with the slack of the belt is pointing back at the camera. It does have a slight deflection, but only a couple degrees. I'm hoping I can resolve that by adjusting the seat or bolt location.

Me neither.

One solution for low profile applications is to swap the sub strap to bolt-in hardware rather than the snap/eyelet style you have right now.

So go with something like this?



I thought these were only to be used in instances where the force was parallel with the mounting surface? Maybe for sub belts it's not as big a deal? I do want to pass HPDE inspection, and would rather not do anything that I'll have to undo if the car ends up racing in the future.

[YosemiteSam]

Where are you getting 3.5" from? I'm looking ant the eyelet (which has to be be vertical) and it only appears to measure about 1.5". I can only assume you are including the belt clip thing in this measurement as well, but the clip thing would be fairly horizontal if you mounted the eyelet a few inches behind the hole.

Edit: Only now clicked on the link and now I see how the 20 degrees comes in to play. That being said, I concur with everyone else, mount the straps farther back. I work in a shop and that's how all our belts are mounted in our race cars. I guess we've just not really read the directions all that carefully.

[Earendil]

Where are you getting 3.5" from? I'm looking ant the eyelet (which has to be be vertical) and it only appears to measure about 1.5". I can only assume you are including the belt clip thing in this measurement as well, but the clip thing would be fairly horizontal if you mounted the eyelet a few inches behind the hole.

Edit: Only now clicked on the link and now I see how the 20 degrees comes in to play. That being said, I concur with everyone else, mount the straps farther back. I work in a shop and that's how all our belts are mounted in our race cars. I guess we've just not really read the directions all that carefully.

Yep, you figured it out. With a max of 20 degrees the belts basically have to attach to the floor someplace that is visible by looking down through the hole, leaving no room for the buckles. Maybe if it were a 5 point I'd be okay, but with a 6 point both buckles will be crammed in there, touching, and likely cockeyed.

It sounds more and more like mounting further back is the way to go. Perhaps I end up changing seat brackets to make sure it doesn't touch the belts on their way back if I can't find a way to comfortably adjust the bolt location and seat.

Thanks for all the tips, guys!

[FredK]

I thought these were only to be used in instances where the force was parallel with the mounting surface? Maybe for sub belts it's not as big a deal? I do want to pass HPDE inspection, and would rather not do anything that I'll have to undo if the car ends up racing in the future.

You are correct, you can't use a part like the one pictured. There is a bent-style bracket that can be used in this case, but you will have to bend it further to get it to the proper angle.

What brand seat mount do you have? It appears you might be able to install a sub strap bar to it somewhere.

[Beej '86 325es]

Refer to my reply in your other post with photos. The E30 is difficult with the ribbed floorpan.

Note the difference in sub-belt mounting between the Schroth and Willans. Schroth says 4" apart at a 20 degrees off vertical, and Willans says 10" apart at 20 degrees off horizontal. It's all in what they tested, yet a very similar harness.

http://www.schrothracing.com/docs/Sc..._Checklist.pdf

http://www.willans.com/download-docu...ilverstone-ld6

[Earendil]

Refer to my reply in your other post with photos. The E30 is difficult with the ribbed floorpan.

Note the difference in sub-belt mounting between the Schroth and Willans. Schroth says 4" apart at a 20 degrees off vertical, and Willans says 10" apart at 20 degrees off horizontal. It's all in what they tested, yet a very similar harness.

http://www.schrothracing.com/docs/Sc..._Checklist.pdf

http://www.willans.com/download-docu...ilverstone-ld6

This makes me feel a lot better, not just about my easily feasible options, but about the way everyone else seems to be doing it :)

Of potential interest, the OMP belts I have (also similar design) say that they should only be mounted to manufacturer belt points, and if that's not possible, to consult the manufacturer. Thanks a lot, OMP :)

[TobyB]

swap the sub strap to bolt-in hardware

Yup- I bolt mine right to the floor with a right- angled strap end. Points pretty much
straight down, since that's the force you're most worried about.

t

[Earendil]

You are correct, you can't use a part like the one pictured. There is a bent-style bracket that can be used in this case, but you will have to bend it further to get it to the proper angle.

I'm not sure what the bent style bracket is. The ones I've seen are either eye bolts (which it seems most installs use), and the 2/3 bar bolt down like I had pictured.

What brand seat mount do you have? It appears you might be able to install a sub strap bar to it somewhere.

Part of my problem in researching solutions was that I don't know the brand. It came with the seat, and was a great deal. For the passenger seat I'm getting a PLANTED seat mount, so I'll have something to compare it to as far as angles and fitment.

AFAIK the belts can't be mounted to the seat if you want to pass most racing tech inspections. Not that I'm racing yet, but I want to be prepared if that happens,a nd not have to go back and "fix" things that I did :)
Not a bad suggestion for an HPDE car though!

[FredK]

You may be able to bolt something like this:

http://store.vacmotorsports.com/vac---harness-anti-sub-mounting-bracket-p2106.aspx

to your existing seat bracket.

I would also check the position of your existing slide bars. They should not be bottomed out against the snap hooks.

Bent plates look like this:

https://www.pegasusautoracing.com/productselection.asp?Product=2388

I bolted seat brackets directly to the floor. My sub straps are snap hook style, with the eyelets placed identically to Beej's setup.

[Earendil]

You may be able to bolt something like this:

http://store.vacmotorsports.com/vac---harness-anti-sub-mounting-bracket-p2106.aspx

to your existing seat bracket.

I would also check the position of your existing slide bars. They should not be bottomed out against the snap hooks.

Bent plates look like this:

https://www.pegasusautoracing.com/productselection.asp?Product=2388

I bolted seat brackets directly to the floor. My sub straps are snap hook style, with the eyelets placed identically to Beej's setup.

Ah, great, thank you for the links! The 3 bar bolt in I posted does have a 15 degree bend in it (which I realize now was not obvious from the picture), so I suspect it would serve the same purpose that the one you linked to does? Perhaps it would depend on if my application results in closer to a 45 or 15 degree angle off the floor :)

I'm still sort of digging the eye bolts + snaphooks, partly because the ability to remove the belts when the car is stored outside is appealing, and partly because all that hardware came with my belts :)