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Posted by: tac27 Mar 8 2008, 03:41 AM

My Dad and I are rebuilding a '72 4 cyl from the 1.7L to 2l; we would like to use the car for both autocross and road course. I've purhcased and installed an Autopower Industries roll cage. For the last PCA driver's education event we simply looped each of the harnesses to the horizontal bar running from one side of the car to the other just in front of the firewall. Unfortunately, I've bee told that the angle from my shoulder up to that bar is too high. So I've thought about getting a harness bar and installing it lower, but I've also been told that the SCCA won't allow looping the harnesses on to any bar for higher speed events, like club racing. My goal is to earn an SCCA licences, so I need the car to pass the '08 GCR. I've been told to attache them to the firewall using large washers, but my impression is that the firewall wouldn't provide much support. Can anyone provide pictures showing where the harnesses should be mounted to meet SCCA club racing rules? Any additional tips and tricks also very much appreciated. A suggestion has already been made to raise the seat mount, but I then have a problem fitting legs under the wheel and dash.

I've included a few pics.



Thanks in advance.

Posted by: SirAndy Mar 8 2008, 07:55 PM

from the pics, i can't really tell, it looks like the straps go around the bar and then down somewhere?

you should be able to just loop them around the bar making the bar the attachment point. as long as the bar is close to the hight of your shoulders.
you should also add something that prevents the straps to slide left/right on the bar.

i don't have the diagram with me, but my 5 point harness came with instructions that showed the range of height allowed in regards to the mounting and the top of your shoulders ...

Andy

PCA, PRC, POC all allow the straps to be mounted on the rollbar ...

Posted by: tac27 Mar 8 2008, 11:03 PM

Thanks SirAndy...
The harnesses loop only around the horizontal bar; the extra length of strap for the right harness is just hanging loose.

My problems it that bar is too high above my shoulder height (according to a couple of fellas at the last PCA DE). I'm 5' 10" so I'm wondering if their advice is a bit off. But in case they aren't I've considered purchasing a harness bar; I would leave them looped to the horizontal bar to which they are now and then down and under a harness guide bar. I stumbled with this idea though from an email from Ken Myers of www.ioportracing.com. He claimes that the harness straps must be secured for SCCA to something other than the roll cage bar and for the 914 to attach them to the firewall (using large washers). It seemed a bit different than what I've seen at POC races, where most were just looped onto that same horizontal roll cage bar. I also just don't trust that the firewall would provide enough strength in the event of a crash.

I plan to add some home fabircated 'guides' to keep the harnesses from sliding along the bar.

Thanks also for the last bit that PCA, POC etc allow them to be looped to the rollbar; everything I've researched in the 2008 SCCA GCR seems to support that too.

Regards,
Tim

Posted by: Dan (Almaden Valley) Mar 9 2008, 12:04 AM

according to Schroth, the shoulder harnesses need to be attached no higher than the level of the shoulders, and can be mounted 20degrees below the level of the shoulders.
take into account the angle of the seat back.
so from what I see in your pictures your belts are currently mounted too high.
I would either weld in another bar under your present one or mount with reinforcements to the firewall. According to Schroth belts may be wrapped. They have alway been designed to be used in this way.

IN checking on the G-Force website they say shoulder harnesses should be mounted form 30degrees above the shoulder to 5 degrees below the shoulder. So even the belt manufacturers don't agree. SFI also uses the 30 degree above and 5 degree below.
You should go directly to the SCCA rules and guidelines since that is going to be your ultimate goal.
In your application you should have harness guides to keep the webbing from moving left and right on the bar.
Hope this helps.

Posted by: jhadler Mar 10 2008, 11:58 AM

SCCA requires that the belts be no steeper than a 20 degree angle from horizontal off your shoulder. A harness guide bar may be used, but the harness must anchor to a structural component of the chassis. A bolt-on harness bar is good for a guide, but not a mount. If the bar is an integral part of the cage, then it's structural.

-Josh2

Posted by: spunone Mar 10 2008, 01:32 PM

ok so you run the belts through the harness bar guide after it's bolted to the firewall is this the way ? anyone with pics? I thought they just wrapped the Harness onto the bar my Bad

Posted by: race914 Mar 13 2008, 09:53 AM

The http://www.914world.com/bbs2/index.php?showtopic=81727 thread in the Garage has some pics of the harness 'eye bolts' attached to the firewall

Here's one from Brant

Posted by: LS6/914 Mar 14 2008, 09:43 PM

It looks like the shoulder harness anchor bar is mounted to high to meet SCCA spec. If the seat is raised then your helmet clearance will be off. Is there a cross bar for the upper windshield brace? Through the years I have run into a lot of PCA inspectors and thier "application" of SCCA specs. My advice is to join SCCA and get the proper info

Posted by: John Mar 27 2008, 01:53 PM

It is going to be subject to individual interpretation, but it seems to be clear:

Posted by: degreeoff Mar 30 2008, 07:18 PM

here is what I did....1/8" plate steel as a reinforcment point that overlaps the top crossmember to add support.

Posted by: drew365 Mar 30 2008, 10:31 PM

Here's the backside of mine.

Posted by: stownsen914 Jun 11 2008, 07:17 AM

Though it's OK to use the firewall to mount harnesses, it is arguably not the best way. Another way to do it would be to modify the cross bar that your straps are currently wrapped around to allow you to attach two eye bolts from the bottom. You would attach your shoulder straps to the eye bolts. You could probably buy yourself a couple inches this way.

If you do go with the firewall solution, make sure to use sufficient backing material. It is best to use something like 4" x 4" x 1/8" steel plates.

Have fun with the new car!

Scott

Posted by: J P Stein Jun 11 2008, 12:53 PM

QUOTE(stownsen914 @ Jun 11 2008, 06:17 AM)

Posted by: 914forme Jun 12 2008, 02:31 PM

4x4 1/8" backing plates are required by SCCA and NASA for anchors of harness attachment points where they go through the body. Does not apply to stock seat belt mounts.

BTW, 5'10" only tells us your overall height, but the critical measurement is in the seated position height to your shoulders.

I added a harness bar to my roll bar. Works great strong as DOM tubing can be.

BTW, my roll bar is upside down in the picture. It was being painted.


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