Shoulder Harness Attachment, Need help where they should be attached. Options

[tac27]

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.

[SirAndy]

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 ...

(IMG:style_emoticons/default/bye1.gif) Andy

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

[tac27]

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

[DanT]

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.

[jhadler]

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

[spunone]

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 (IMG:style_emoticons/default/beer.gif)

[race914]

The Firewall Access thread in the Garage has some pics of the harness 'eye bolts' attached to the firewall

Here's one from Brant

[LS6/914]

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

[John]

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

Harness Systems: If the participant chooses to install a 5 or 6 point driving harness (four point systems are not safe and therefore not allowed) several changes to the automobile must be made to create a safe occupant restraint system. Harnesses must include an antisubmarine strap and be mounted in an approved manner consistent the manufacturer's instructions. The Harness system must be used in conjunction with a seat which has the supplied routing holes for the shoulder and anti-submarine belts. All pieces of the restraint system must be installed in accordance with the manufacturer's instructions.

This means that a seat is required to have the proper routing holes for the harness as supplied by the seat manufacturer for the shoulder and anti-submarine straps. The shoulder straps should be mounted at 90 degrees to the axis of your spine or at most 40 degrees down from horizontal. Because the addition of the harness system means that the occupants are fastened upright in the vehicle, a properly padded roll bar or roll cage is strongly encouraged to complete the SYSTEM. The use of one without the other may result in an unsafe environment and is not a COMPLETE SYSTEM. Due to UV degradation and wear, the harness webbing must be replaced every five years.

To me, it looks like PCA requires the shoulder harness to be mounted 90 degrees to your spine or at most 40 degrees DOWN from horizontal.

It seems to make no mention of routing the webbing around a guide bar (which I will be doing).

[degreeoff]

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

[drew365]

Here's the backside of mine.

[stownsen914]

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

[J P Stein]

Though it's OK to use the firewall to mount harnesses, it is arguably not the best way.

Scott

Granted, but it fulfills the KISS precept....a rule to live by, me thinks. (IMG:style_emoticons/default/biggrin.gif)

[914forme]

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.