Okay, I am going to try this, and I don't mean to start a controversy... From the archives I see that this is a touchy subject...

My wife bought me 5-point harnesses(H-type) for our anniversary and along with that a harness bar(Awesome Gal!!). This is going into my 89 951 and will be used at DE events.

From what I know so far from everyone on the list I am going to attach the shoulder straps over the harness bar and connect them to the factory mounting points on the rear seat.

As for the lap belts I am going to use the factory mounting points right now. My question is this, since I am trying to keep the usage of the 3-point belts, how have others mounted the brackets to the mount points?

Or, is this impossible... You know, like other people, I am attempting to get my self in the position of using both. The car doesn't see daily use and I am wondering if I need to forget using the factory belts....

Pictures would be great too..

Thanks Rennlist Brethren!!!
Z

 

David
Brey Krause makes seat belt mounts just for this purpose. You will need one of each of the following:
www.bkauto.com/porsche/r9001.php
www.bkauto.com/porsche/r9003.php
you will also need four snap in plates.
All of which can be had from OG Racing. You can order directly from our website www.ogracing.com or call us at 1-800-934-9112.
If you have any questions please feel free to ask.
Dave Parker
Manager, OG Racing

 

Thanks for the information. Lori actually bought the lapbelts from you...

 

Hey Dave;

It's not really a touchy subject. There are just degrees of compromize. Everybody has to make them according to their intent and their ability to understand the parameters. Usually, you can bet that those who are "touchy" are also those who are less than fully informed.

You can go with the BK stuff. It is a decent solution. However, sometimes it "CAN" create problems like poking you in the butt, or raising the belts to a point where you run out of adjustment. In other words, it effectively moves the mount point closer to the latch, and you can sometimes not be able to tighten the belts because you have run out of travel. I don't know if this makes any sense at all. It is very tricky to describe. It is VERY dependant on what size you are.

Or... you can simply mount both on the lap belt bolts. You will trap the harness under the bolt, and allow the OE belt tab to rotate as usual. When you trap the harness, you must carefully set the angle the belt pulls at to match where you sit, then lock the bolt down. This is not perfect as it limits correct belt pull to only that size driver, but it does work out fine. You may need a slightly longer bolt for the inner mount to the seat frame.

For the average guy, the BK stuff is probably the way to go. For those with some creativity, the other works just fine too.

As for your rear belt mounting, I'm NOT in favor of it. Running belt paths that long creates a very high degree of elongation of the material if you biff. Belt paths should be as short as possible. That means mounting DIRECTLY to whatever bar you have. If that bar is not mounted to something very solid, or is not up to spec for such use, you have the wrong bar!

Mounting in that fashion is a compromize. We ALL have to make them, and you may choose to make this one, but it is NOT ideal.

 

Dave:

I will be installing a cage in my 968 and will have a Redline roll bar for sale that i think is a straight bolt in for the 944. Is that correct John?

Thanks, Mike

 

Don’t attach the shoulder belts directly to a “harness guide bar”. Only attach the shoulder belts to a bar that is designed for direct attachment and is not sold as a “guide bar”. Most bolt in harness bars are guide bars and are not tested for or strong enough for direct attachment. The paperwork that comes with the bar will be specific as to belt installation. It is true, running the belts all the way down to the rear seat lap pickups makes for a long strap and will increase elongation. A direct attachment bar is better.

 

The harness bar should be made of roll bar stock ( I think Weltmeister is) and you should fasten the belts directly to the bar. Fastening the belts to the rear seat belt mounts increases belst stretch and increases the force on the bar. This has been a matter of some debate in the past, but anyone who has taken a freshman course in statics will concur with the above. Others may not, including the PCA DE boffins.

 

Thanks for all the help and advice... I think I have I am going to go to the bolt in red line bar, not sure when, but that might be my first coarse of action... Then someday goto a new seat...

Just as a side note, I have found that the harnesses don't fall off my shoulders, which is a good thing.. The "H" type belts work fine...

Z

 

For my track car, I use the Redline roll bar - no affiliation - plus Corbeau CR1 seats with shoulder harness holes, and BK seat belt mounts. The Corbeau seat slider comes with an integrated seat belt mount on the tunnel side, so you can mount both the stock belts and the 5-point there with the BK adapter. For the sub-strap, I had an upholsterer make some proper holes in the seat bottom, although I ran for a number of years with the sub-strap around the front of the seat. This is not a full-race set up, but I find it a good compromise for a DE car that is driven to and from the track - sometimes a long way. For me, the stock seats did not hold the shoulder straps securely enough. All of this can be removed, and the car returned to stock. It worked ok last year when I hit the wall at Mosport and wrote off my car. My new car had a roll cage, but I removed it and am putting in the Redline roll bar. Personal preference, but life is too short to pretzel in and out from a full roll cage on the street, and it wasn't safe without a helmet on the street anyway.

 

David;

Sled testing has shown that it is fairly important how close together the belts are at their mounting point. If you pull on a belt, it will try and straighten itself out, even if it is bending around some object, like a stock seat back. Even though it cannot straighten, the forces in the material are trying to do this. This consequently helps the belts stay up on your shoulders - closer to your neck - instead of sliding off.

Therefore, it is important to mount them fairly close together, and the longer the belt behind the seat, the closer they should be. If that distance is 12", set them, no more than 5" apart. If it exceeds 16-18", they should be CROSSED. Considering you have "H" belts, I would do everything but cross them.

And let me know when you're ready for that roll bar!

 

Hmmmm....I am not too sure on the roll bar just yet... After the harnesses and bar, I have to somehow break that to the miss's

Thanks!!

 

Dave Z. Lots of debate on these issues. There is a real lack of credible test data on all the various setups you see at the track. Not trying to scare you, but it is something that is worth significant thought.

Just for the record, I think there is a "soft" concensus over the following.... Full race setup (Roll Cage, 5-Points and one-piece FIA seat) is a proven system.... factory belts/bags/seats are a proven system. Mix and match (5-points with factory seat for example) is unproven system and may or may not be safer than using the 3-points.

For example, in a collision, your body tends to compress the factory seat. If you are wearing 5-points the lap belt will tend to ride up over the hips onto your abdomen. If the sub-belt is looped over the front of the stock seat it will do nothing to position the lap belt. This is potentially dangerous.

Also most folks believe that a "sternum strap" holding the shoulder harnesses together at your chest is not the optimum and could be dangerous. The acid test is not how the harnesses fit when you are just driving around, but how they will react in a high-G impact. Harnesses should be located by the roll bar or failing that, a harness bar. Any other approach is probably not going to be reliable when you need it.

All of this is theory. There are opinions either way (and you can read most of them on this forum). The best you can do is educate yourself and make your own decisions, but it is good to think about this.

Personally I am very leery of 5-Points with stock seats. I have done it in the past, and fortunately had not opportuinity to test their performance but now, I would not do it, but that is purely my own belief... I have no hard test evidence to prove that the 3-points are "safer". If you are going to do this, however, I would highly recommend the suggestion to have a sub-belt opening put in the seat.

BTW. You should mount and use the harness bar based on the manufacturer's instructions. "Stretching" of the belts is still preferable to complete failure.

 

John (redline) - What kind of tubing bender is that? I'm thinking about getting a Model 3 from Van Sant.

 

Actually...

There is data out there. It is just exceedingly hard to come by.

In my considered opinion, you are probably safer in more situations with a harness than without. This assumes proper installation, which is another sticky wicket. There are certain areas that harnesses with stock seats are indeed a real compromise, and so I don't recommend doing it unless you absolutely "must." If you DO have to, drive accordingly!

The largest deficiency of this setup is lap belt control. I think it is IMPERITIVE that you use a "Formula" or "D-ring" style rear mounted sub because you will not get quick take-up or lap belt positioning - and hence hip rotation control - with a sub mounted over the front of the seat cushion.

IF you can get good lap belt control and quick take up, the chances of the seat pulling the belts of the shoulders is greatly reduced because the torso will not transition down as far, the point JCP made about sinking in stock seats notwithstanding.

Again... not an ideal setup, but I feel it can be done to reasonable effect.