kary993

Bill, I suggest that you move the loop to the upper bar and you make sure that the loop is tight to the bar because it will slide in or out in a situation. You should also triple loop because they will slip as you have them now.

RedlineMan

Oh, that's horrendous, Bill;

Nothing personal, but this old long belt path thing is real no no, and you are quite wise to ask. Lots of people used to do this before everything was so intensely vetted as it is today. You should most definitely be using the upper bar. It appears to be an ideal distance from your seat.

This will clear up two big problems you have there. 1) it will shorten the belt path, thereby reducing elongation of the material, and better keeping you off the dashboard. 2), it will allow you to get a proper amount of belt tail past the slider bars. Your "scrap" belt tail is far too short here. You need at least 4", because these babies slide a LOT.

A third problem is you have a bit too much free area between your slider and the belt bar. You need to reduce this free slack in the loop to a minimum, but not so much that the loop will not rotate freely and seek a straight pull from the bar. If you get the loop too tight, they can cam-lock themselves and not pull straight from the bar until a large force is applied, when they then rotate around and enter unwanted slack into your belts even after you tightened them as tight as you could.

I cannot quite say about the positioning loops, as it is a bit hard to tell from the photo. They should place the belts just slightly narrower than the belt holes in the seat, down to a minimum distance apart of about 3".

Finally, Kary is right about the triple wind of the tail. You will have enough slack to do this once the belts are on the top bar. These appear to be TRW/Sabelt, and they are an absolute pain to triple wrap. I have to use a screw driver and a pair of pliers to force the tails through the third time!

fatbillybob

Uh? I'm not smart enough to do anything but regurgitate the conventional wisdom To my understanding that means to the roll cage. Now what I'd like to see is more pictures of different designs of seats and anchors mounted to cages. 99% of what I see is cages to car and seats with anchors welded/bolted to 18g tin floors.

kary993

I use some strong needle nose pliers to pull the belt through on one side and then work it through across until it is all the way through. A real pain but well worth considering some of thebelts I have seen slip!

RedlineMan

Alan;

You obviously have some very serious metalurgical expertise. All I know is that the steel used for belt hardware is some really dense and hard stuff. It is very resistant to cutting, grinding, or bending. That aint by accident, I wouldn't suppose!

RedlineMan

You're such a tease! OK, I'll take the quiz!

- Lap belts should be positioned at somewhere approaching a <60 degree angle from horizontal as they pass over the hips.

- The mounting points should be as close to the seat as possible, and allow the mount plates to rest roughly parallel to it, while still giving adequate clearance for free movement of all hardware.

- The end plates should pull straight off the mount point, and pivot freely in a range from at least the static 60 degrees + to at least 45 degrees from horizontal to allow for forward torso shift and subsequent belt rotation.

Hope I passed!

gbaker

Sorry guys, I was afraid of making public something someone may have in a pending patent application, i.e. of spilling someone else's beans. After a phone call this morning we learned the idea has been around for a long time. The racing industry just doesn't get it (sound familiar? ).

These are all very good, as far as I know--don't forget that the harness thing is not our specialty. But John, if it were a snake it would have bitten you when you said, "The mounting points should be as close to the seat as possible..."

Almost: The mounting points should be the seat.

This is not our idea, but when we heard it, it was one of those flat-forehead moments. The seat manufacturer installs the belt anchors on the outside of the seat before it ships, as close to the belt ports as possible. This means:

- the position is correct
- the angle is correct
- the belt length is minimized
- the belt can be sown in at the anchor (no aduster/slip)
- relative motion between the belts and the seat is minimized...

From the safety perspective there are no negatives. As a customer I'm all over it just knowing that the set up is professionally designed and installed at the factory and I don't have to do any car mods. The manufacturer will charge a premium--which I am happy to pay given my savings--and any distributor/dealer will now be selling a higher priced product and probably belts to match.

Is that sweet or what?

(BTW, the military has been doing this since the 1940s.)

Bill Verburg

Thanks for the advice guys, the bar has onlly been trial fit into the car, I was fiddling w/ the possible methods of running the webbing, upper bar it is, the slider as close as possible to the bar,

Now the triple loop part has me puzzled. Does the tail go in the side it first entered again, or ????

then how to deal w/ the rest of the tail, roll it up?/

Larry Herman

We guessed that, honest we did. Now all you have to do is make damn certain that the seat stays put during impact.

RedlineMan

Thanks, Teaser!

That is very interesting, as I have been doing just that in certain situations for some time.

We DE folks need quite a bit of flexibility because we like to hop around and drive different cars, test people's setups, check for mechanical problems for friends/customers, swap rides, etc. This reeks havoc with belt adjustment, PARTICULARLY sub straps.

I usually mount customer DE seats on sliders to maximize their flexibility, and I have ALWAYS mounted my customer and personal subs to the bottom of the seat because this allows the use of sliders and you still then have a sub that is more or less properly adjusted for everyone. You can't do that with a floor mounted sub.

I did a 6-point cradle sub setup in a friend's 996 a couple years ago, and ran the subs out through the lap belt holes and mounted the plates to the side of the seat. I did not quite have enough belt to go to the lap belt mounts, and it made things too busy and cluttered anyway. Guess I've been on the cutting edge all along!

Now, I was thinking EXACTLY the same thing as Larry when I read your post, Greg. I think with a seat on sliders... I want those belts mounted elsewhere! Especially with my bulk in that seat. Now, if you had a Fort Knox seat like FBB is thinking about building...

fatbillybob

John, GBaker, Larry,

I slapped my forehead so hard I gave myself whiplash! This has morphed into a really great thread. The harness system on the seat you speak is really the CART/F1 monocoque. I hear and believe what you guys are saying. However, here is a real life problem to this very advanced idea one that is theory and one that is reality. First, I own a 348 Ferrari. It had part of the harness system mounted to the seat. The real life problem is while the design is a forehead slapper great idea, they mounted the seat to 18G sheet cross member on the floor and with 8.8 class 8mmx1.25 bolts with no grip so that the threads were in direct shear! The seat is 45lb and the 200lb drive make for some serious G loads on the seat anchors. It that really within the design need? I can't do this math. This leads to Larry's short comment about keeping the seat in the car. IMO the seat (in a tintop car) even an ultrashied would need a severe redesign to be used in this most ideal manner. Finally, could your pass tech with such a design? I guess they just say 5 or 6 pts securely mounted?? I even question John's use of the subs mounted to the seat as now you have two less anchors to the roll cage should the seat anchor fail. 6 Seat belt anchors have a 1/2" hole in them for 1/2" hardware . Typically, people use small hardware like 8mm for seats in four places. We would need a major seat redesign and the new problem would be mounting the seat with its new factory reinforced anchor points to a specific ergonomic position in the car which may or maynot be possible without the FBB Fort knox seat frame. However, what a great design for turning and aluminium Acura NSXor a 360 Ferrari into a race car. You could take an aluminium Ultrashield and weld it to a fixture welded to the aluminium frame of the car. Then....O.K. I'm thinking too much again...

Larry Herman

The factory mounting of the seat is certainly the weak point. 8mm bolts? My snow blower uses 8mm bolts as shear pins for the auger! LOL.

RedlineMan

No Bob...

I don't think you are over thinking THIS aspect of the project. Obviously, it is a very important one. I like mounting alloy seats using flat stock alloy or steel side panel that place everything in shear over a very large surface, and use 3-4 equi-distant bolts per side. I am moderately dubios about the available aftermarket side panels, as I feel they do not quite offer enough lateral resistance to folding sideways. If they were webbed and/or triangulated, I would feel better.

I would build something like this;



The laterals here, made of round steel tube for strength, would be welded to whatever exisiting structure was there. The longitudinals, made of steel square stock for a flat mounting surface, would be placed directly where your side panels fall.

Now, if you chose to tube the existing rocker and tunnel areas, you could weld this entire assembly to that tube structure. As I mentioned before, I think that tubing the exisiting longitudinals is a bit of overkill. You can web and weld into the existing structure quite effectively.

As for bolts, nothing wrong with 8mm, but I would not be relying on only 4 of them. I would be using 4-per side mount flange to the base, and 4 into the side panel of the seat. Spreading the load across a wide area between sixteen 8mm bolts would be quite stout!

gbaker

Agreed, but that problem will eventually be solved for another reason.

A lot of attention is being paid to lateral loads. As seats are improved to provide increased side support designers will face the problem of anchoring the seat to take these higher loads, regardless of where the belts are anchored. Once the seat mounting is designed to take the full body mass in a large lateral hit, it will necessarily be strong enough (roughly) to take the full body mass in a large frontal hit. Problem solved.

As an interim step one can see the seat manufacturers putting anchor holes in the seat so the user has the option of anchoring the belts there or going the conventional (for racing) route of anchoring elsewhere.

Bill Verburg

OK, let me rephrase that, iathis what you man by triple loop?