belt setups?

[Bruce Jibboo]

While road racing I notice way too much movement in the seat, resulting in bad driving inputs. Anyone go beyond their seat belts for greater restraint?

I think the options are attempting to use the factory seat belt "cinch", a CS lock device (center of gravity) which is a belt locking mechanism, or full 5-6 point harnesses with supporting mods.

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[10sec]

Why don't you get a nice recaro race seat? You'll always be sliding around on factory seats, you need a nice race seat to hold you in place. I instantly was able to tell I could focus much more on driving than trying to hold myself in place. The S2000 has MASSIVE amounts of grip.

 

[Dan00Hawk]

I have a Schroth 4 point in my Firehawk that I've used for autocrossing and roadracing. It keeps me in place just fine, and I just leave it on the rear floorboard when only using the OEM 3 point. For our Lemons car, we obviously have a deep race seat and a full 5 point harness, but that would be a PITA for a street car. The 4 point is more user friendly but still keeps me from sliding around on the leather factory seats.

 

[Bruce Jibboo]

Did you have to install an up top bar for the shoulder straps?

 

[Bruce Jibboo]

Why don't you get a nice recaro race seat? You'll always be sliding around on factory seats, you need a nice race seat to hold you in place. I instantly was able to tell I could focus much more on driving than trying to hold myself in place. The S2000 has MASSIVE amounts of grip.

Also some of the reading I did said racing seats were required, the 5 pt straps will wear the hell out of the factory seats

 

[sickmint79]

i was wondering what i could do in the past but if you go religiously faithful it seems the option is a binary go all out (in which case it's fucked for street) or do nothing and keep the stock stuff. anything else it seems people note all sorts of new ways you open yourself up to getting fucked.

i'd try that cs lock and see if you like it before anything else. i assume it's a simpler way to just do what i'm already doing (are you?) which is the poor man's harness:
- move the seat back all the way
- suck in your gut
- quick pull on the belt to lock it
- move forward to your normal driving position
- let that gut be free again
- mass now locked in place with your mass

it's certainly a step up from being loose if that is your current situation.

 

[Bruce Jibboo]

Agreed, I'm 99% sure I'm going to go down the seat belt lock route, they call it factory option "cinch" in the corvettes. If it holds up, I don't think the CS lock adds any value beyond that.

 

[Pressure Ratio]

I am no expert but will add a few things to think about.

I tried the CG Lock (This one) and it didn't work that great. Mainly because it would not stay tight on the seat belt buckle. I would tighten it after every session and it came off 50% of the time. My belt buckle was rounded so it didn't have much surface area to hold onto with the CG Lock's flat clamping area.

The method sickmint79 mentioned works well. A driving instructor told me that trick and I used that with no issues. The only difference was before I clipped in the buckle he had me twist the buckle twice so the belt locked the buckle in place. I suppose that was in case the shoulder locking mechanism let go, you still had the lap portion tight due to it being twisted.

An issue I have seen with stock seats is where the harness goes over the seat can cause the belts to be away from the body. As well as putting the belts in odd angles. Like the shoulder, belts are spread too far apart due to a wide seat or headrest. So you may want to see how the harness would lay over the seat and yourself. You can always modify the factory seat to have the belts pass through in the correct spots. I have seen where people cut the foam and had the cover stitched with an opening for the belts to pass through. But that has to be done properly as well. If it is under the structure and just being supported by foam the belts will not be able to work properly.

The other thing you touched on in shoulder harness mounting locations. Do not use a set up that goes to the floor behind the seat. In a roll over the seat belt will actually pull your shoulders down and compress your spine. They need to have attachment points higher than the floor. Some kits I have see attach to the factory rear baby seat mounting points. It is a better location than the floor. But I am not sure they would be strong enough to hold the harness with the weight of an adult and the forces they might see. As they were designed to hold a small child in a seat. Maybe someone has more info or experience with these set ups?

 

[Bruce Jibboo]

Here is more issues specifically with the vette, pretty sure the supporting mods and 5 pt were about $1200 (800 or so for top bar).

1. When the shoulder belts go around the side of the seat they will wear the seat at the point the belt pushes the seat fabric against the inner seat frame.

2. Since the belt is wrapped around a flexible/frangible part (the seat frame) it will collapse the frame under a hard impact thus letting your body move forward.

3. If you put pass throughs in the seat back you have issues with the path of the belt since the pass through locations may prevent it from traveling in a straight path from its mounting location to the top of your shoulder. If the belt is deflected in any manner by the pass through the seat becomes part of the belt system and you have the same situation as going around the side of the seat back. I even converted the seat backs in my 03Z06 to the Sport Seat style with the hole in the seat back that didn't work either.

4. Even after you do all of that stuff the belts don't do much more to keep your body from moving around than if you just used the stock belt in cinch mode. The reason is you are trying to use the belts for something they aren't meant to do. The seat is the item that is supposed to keep you in place in the car and the belts are meant to keep you in the seat. The belts do not provide any lateral support at all. Only the seat can do that. If the seat doesn't have lateral support the belts won't give it to you.

At a minimum you need a seat that supports your shoulders so you just let your body lay against the supports in a high G corner, deep wells that keep your legs from moving sideways, and a bucket for your butt that keeps it from sliding around. When I first went to race seats I had a little bit of a weight issue and installed a 17 inch wide Ultrashield aluminum seat. It was snug and held me in place. Last year I addressed my weight issue and lost 60 lbs. Now I can fit in a 15 inch seat. However, even with two inches to spare in the seat which allows my body to move around some the seat still holds me in the car far better than any of the stock seats did.

 

[Intel]

Another thing to think about with going the 5 or 6 point route is the need for Head and neck restraint. Once you hold your body in place the only that that can move forward is your meaty brain dome and your arms.

If it were me I wouldn't go the 4 point route as I don't trust them to keep me from submarining under others will disagree. At least the Schroth ASM seems to account for this somewhat.

I used a cg-lock in my maxima when I autocrossed with leather seats and now in my Mazda3 with cloth seats. Not saying I am hitting the G's of a vette but it works well enough for me.

I am kind of having this sort of decision making with my Datsun 510 as part of me wants to track it but given it is a 2400 pound tin can I would want at least a roll bar but then it becomes less of a street car then I would want it for most of the time. . I feel 10x safer in my Mazda3 with stock belt setup/crash safety of a newer car. It just feels dumb to not track the more capable car.

In a perfect world I would have a caged car with fire system/cutoff/fuel cell like our chump car. Then I go down the trailer/truck role and the fact that my fiance doesn't want me to have a "racecar" because it is dangerous.:rollpicard:

 

[Dan00Hawk]

Did you have to install an up top bar for the shoulder straps?

No top bar necessary for my setup. The Schroth attaches at 3 points. The two bottom points are at the rear of the front seat supports, which is where the lap belts come across. And the third point is the rear seat fold down latch bolt which is fairly high up, and it splits off into the two shoulder straps.