I just picked up a set of anti-submarine belts to upgrade my setup from 4 point to 6 point. Where/how do you guys have the belts hooked to the car?

Non-stock seats... they are recaros.

Thanks
-paul

 

Through the floor backed by very large fender washers.

 

I had a set of extra steel plates from an Autopower roll bar. I drilled a centre hole in each of the 4 plates and used one for each mounting point for the driver and passenger sub straps. Drilled through the floor, bolted through the floor and plate on the outside.

 

I zip-tied it to the wiring harness.


Seriously, I have a metal cross bar bolted cross-wise under the seat rails.

 

The sub belt does not see the forces the main harness does, so you don't have to go overly crazy on it's mounting. It's purpose is to keep your main lap belt low, and on the boney part of your hips during an accident. If the lap belt slides up off your iliums, then the belt gets into the soft tissue of your body and can cause serious internal injury (ie, spleen, liver, etc). Just make sure it has a good size backing washer or plate, and that the sub belt is nice and tight when clipped in. Also, it's mounting point should be behind the slot where it goes through the seat, and not in front of it.

 

pics of the said recaros

 

The sub strap harness ends are bolted to the vertical plane of a length of angle iron, which is bolted through the floor to a very large backing plate. I made seat mounting reinforcements out of angle iron as well. Heavy but extremely solid, I think my seat would break before the mounting points would fail.

 

Bolted through the floor.

I used a set of 2"x 3" heavy plates with "captive" bolts, but also installed a larger (12" x 9") thinner sheet of steel as a washer's-washer between the plates and the floor. The floor material on the 944 is paper thin and extremely mild. It is not hard to imagine even a large washer ripping through the floor.

As noted, the sub-belt may not be the highest-stressed point. I used existing seat belt anchors everywhere else EXCEPT the inboard lap which had to be relocated. I found a solid frame member to bolt through for that one.

 

Don't underestimate the forces on the sub straps.

Belt forces during a 31mph frontal 90* head-on impact with a 165# dummy:

Lap belts 3100# each side
Shoulder belts 1550# each side
Sub straps 1320# each

 

Same attachment point as the lap belts - using longer bolts than stock, but in the stock 3-pt belt mounting point. "Used" this arrangement a number of times, most recently at Road Atlanta in Nov...

 

Best shot I have at the moment. The front part by the crotch is adjustable and slides forward so the sub straps would go behind that. Not ideal and it won't pass a "true" tech but I have to deal with what I've got. I also was reading one of the many .pdf files about harnesses and I have decided to route my shoulder belts through the headrest posts instead of on the side of them. I think there is enough room on the outside but it doesn't hurt to put them on the inside (according to what I've gathered)





How far behind does it need to be? I would prefer to run a metal bar across the front seat mounting bolts and hook into that. Being short my seat is forward some so I should be fine. The passenger's seat (or just taller drivers) may have issues.

I may end up making a "H" bar for under the seat to push the mount point back farther. I just want to get this done before May 23rd. (lapping day!)

 

they came with the car? nice and comfy

me = fixed-back seats

 

I'm not trying to be mean here... but those seats were NOT designed for use with a harness.

I guess this falls under the: if-you-have-a-$10-head-get-a-$10-helmet category...

 

+1

Looks sketchy

 

Well aware of it. That is why I'm not even going to try to do any real racing etc with it. The harnesses just hold me in better. I really need the anti-sub belt to keep the lap from walking up into my gut.

The real racing guys here are missing my intended purpose. The car came with the lap belts and harness bar in back, so for the cost of shoulder belts and now the antisub belts I get to worry less about me* in the autox and more about the car. I currently envision this car to be 90% summer fun car, 10% auto-x lapping day etc. That puts different seats in the not-worth-it category.

*not crash wise, being thrown around while turning wise.