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mod/classing question

Old Oct 31, 2005 | 05:02 PM
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mod/classing question

I'm thinking about installing some kind of bar to hook up a harness to (using my stock seats, since I don't want to remove them) and also to use as a camera mount too. Here is a rough sketch of what I'm talking about...would mount to the floor behind the front seats.

Would this affect classing (i.e. would it qualify as as frame bracing or anything), or would I be ok with this in STX/STU?

here's a drawing:

Old Oct 31, 2005 | 07:58 PM
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depending on the inspectgor, it could be construed as a chassis brace.

but, IIRC, there are specific rules listed about harness bars and their mounting and use. see the sections on that and see what they have to say.

FYI, the pic you're showing isn't exactly structurally sound. your left shoulder harness will be able to bend the bar under hard braking or other high tension on the shoulder strap. it needs to be attached to the B pillar somewhere for some stability at the top.
Old Nov 1, 2005 | 05:20 AM
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It's been a while, but I believe Autopower makes a bar that allows the REAR down tubes to be removed to allow the rear seats to be used as needed. I remember seeing one being installed in an M3 a few years back.
Old Nov 1, 2005 | 11:25 AM
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Try asking Sparco what they offer. Their bars are a very clean design.
http://www.sparcousa.com/harness_bars.asp

Or you might try AutoWeld south of you. The apparently have a design on file for a full A31 bar/cage already.
http://autoweldchassis.com

Usually these are fine for tech. Except that one "could" argue it's offering structural bracing. The only altenative in that case is a b-pillar camera mount bar but those need to be really strong to support the weight.
Old Nov 1, 2005 | 12:08 PM
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just FYI, I got this email back from Doug, the national SCCA tech guru:

Hi, Josh,



The last part of 13.2.H says: “A horizontal “harness bar” may be used as part of the installation hardware for allowed driver restraints. It may serve no other purpose (e.g., structural enhancement).”



I believe the component in questions would not be compliant because it would have another purpose, structural enhancement. It may not have been intended to create structural enhancement, but it would.



A few years ago the SEB ruled on a roll bar in a Stock car that was not built to the specs in Appendix C. Even though it was marketed as a roll bar and had data to support it’s effectiveness, the SEB basically said that it wasn’t a roll bar according to Appendix C and as such was not allowed by the Stock category rules. It was allowed by 13.2.A “C&C” either because it added structural enhancement to the car.



I believe the answer would be the same today – if it’s not an Appendix C compliant roll bar, it serves another purpose as structural enhancement. Even if a harness bar is attached to the standard shoulder belt points on the B-pillar, there are some who believe its adding structural enhancement. So attachment needs to be carefully thought out.



Another thing I noticed in the thread is the idea of an “SCCA–approved roll bar.” SCCA doesn’t approve anything – it meets the SCCA rules or it doesn’t.



I’ve seen some harness bars that used heim-joints to prevent the dreaded structural enhancement.
It appears that SCCA rules are vague as ever on this subject....what construes "structural enhancement"?? Only God knows. I wonder if leaving my roof rack on would be "structural enhancement"

good thing I have all winter to think of something!
Old Nov 1, 2005 | 12:16 PM
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the other point is that I would want this to be bolt-in....don't want it in the car except at events....questionable how much any bolt-in bar would brace the frame at all.
Old Nov 1, 2005 | 12:18 PM
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Originally Posted by Matt93SE
FYI, the pic you're showing isn't exactly structurally sound. your left shoulder harness will be able to bend the bar under hard braking or other high tension on the shoulder strap. it needs to be attached to the B pillar somewhere for some stability at the top.
it was just a sketch to question the legality of using a bar with a back brace....I would have it made at Piper Motorsport locally here, and they have decades of experience at this kind of stuff....I'm sure they'd make whatever design was strong enough (not necessarily what I drew)
Old Nov 1, 2005 | 04:28 PM
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Originally Posted by irish44j
the other point is that I would want this to be bolt-in....don't want it in the car except at events....questionable how much any bolt-in bar would brace the frame at all.
Kinda like bolt-in strut tower bars don't brace at all
Old Nov 1, 2005 | 05:13 PM
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Originally Posted by irish44j
It appears that SCCA rules are vague as ever on this subject....what construes "structural enhancement"?? Only God knows. I wonder if leaving my roof rack on would be "structural enhancement"
Well the all knowing SCCA rulebood puts Mini-S's against maxima's, why do woud you expect anything different?

Originally Posted by irish44j
good thing I have all winter to think of something!
Old Nov 1, 2005 | 08:21 PM
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Originally Posted by BEJAY1
Kinda like bolt-in strut tower bars don't brace at all
they are bolted directly to suspension components (strut towers) - i.e they have a direct effect on the stiffness of the frame at one of its "most stressed" areas. Anyways, the FSTB has a minimal effect at best IMO. I ran one event without it on there (lost a bolt) and felt no difference at all.

What I am referring to would not link any subframe sections, but would just bolt through the floor. In any case I don't run points series anyhow so might just do whatever I want and have a good time in the basement of some higher class....I autocross for fun. If I wanted to "win" I would do it in a different car than a maxima...

I'm sure the guys at Piper (who are all long-time SCCA guys) will know how to make a setup that will be STX-legal though, so I'm not too worried about it at this point.
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