924Board.org

[CorsePerVita]

I opted to go with a Schroth 6 pt profi ii. I went through and looked at what seemed safest to me and I figured that was a good choice.

However, I'm struggling with conflicting info about what is "safe", what is a "compromise" and what seems to be the "best" way about mounting it.

Obviously the sub straps need to be mounted 100mm apart (4") and back a hair under the seat. That I think will be fairly easy to do. I need to measure and remove it.

But what I am actually struggling with is the conflicting info I get about the lap belt.

http://www.schrothracing.com/store/Competition/profi/profi-II

Now, it says the angle for the lap belt should be about the same as the sub straps. I see, however, through a lot of 944 and 924 posts that people use the stock belt locations. But for me, since I'm fairly short in reaching the pedals and prefer to be up closer, is that my lap belt does not stay flush with the provisions made for them.

Here's an example. Basically, where I slide my seat, at the angle it ends up meeting the provisions, it would end up bolting about where the ebrake handle bolts up. (I put a 13mm bolt in there just to see if the angle was right) and it looks like this.



If, however, I bolt the lap belt where the stock belts are and slide my seat where things "feel right"... it scrunches, and ends up at an angle. Example.



So here's the thing is that I could definitely drill in underneath and everything, but already having the substraps under me under the sheet metal EVEN WITH the backed plates I realize is "fine" but since the stock locations are well reinforced, it would be hard it seems to drill in and make another "reinforced" spot. I don't want to mess with the integrity.

Is the angle of the stock belts indeed "ok?" and within an angle that is still acceptable? Or is it definitely unacceptable? I'm trying to understand this and find the SAFE way to do it.
_________________
- 1977 Porsche 924 2.0 N/A (Trackday Project)
- 1979 Porsche 924 2.0 N/A (The other daily)
- 1980 Porsche 931 (Daily)
- 1987 Lamborghini Jalpa
- 1999 Ducati 900SS

[Rasta Monsta]

Lap belt mounting points are fine. . .everyone uses them.
_________________
Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[Andrew NZ]

[CorsePerVita]

Statistically it's been shown that a lot of drivers install their harnesses incorrectly and make even simple mistakes with angles and safety of their stuff. Not everyone's body is the same and the way that everyone sits is not within the same proximity to things that you may be. So that doesn't address my concern.

Would my proximity in being as short as I am in comparison to proximity of "feeling comfortable" be safe to consider using those. Just because everyone uses the same points does not mean that it is safe for everyone.

That's why I wanted to bring this entire thread up, to address that... what is safe? What isn't safe? What will prevent injury? You can cause more harm with an improperly installed harness than if you just used the standard lap belts. So what is the safest way, and the best way of ensuring that safety, via angles, mounting points, in our cars varied from person to person?

I got in contact with a few people over on rennlist and one fellow had an entire article for PCA regulations that completely changed how I looked at harness installations which is what made me question how I was even considering installing mine in the first place.
_________________
- 1977 Porsche 924 2.0 N/A (Trackday Project)
- 1979 Porsche 924 2.0 N/A (The other daily)
- 1980 Porsche 931 (Daily)
- 1987 Lamborghini Jalpa
- 1999 Ducati 900SS

[Rasta Monsta]

Assuming the seat is mounted properly, the lap belt can use factory mountings. If you can get them tight, you are fine. Subs will be mounted through the bottom of the tub with supplied backing plates, and are not really loaded up. The critical ones are the shoulders.

Do they come straight through the mounting holes from the bar? If they have to go UP to get to the holes, you have a problem in a frontal impact, as the seat can buckle from the shoulder harnesses wanting to be in a straight line from the force. Another concern with a short driver is the distance from the bar to the seat back. If you don't have an FIA-approved seat, the seat can fail in a rear impact unless a seat back brace is installed.
_________________
Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[CorsePerVita]

The shoulder straps are just about dead on even with my seat, they do not have to come up at all. Thanks for the clarification on things James. I do have an FIA rated seat. Is it true that I have to replace it every x years (the seat)?
_________________
- 1977 Porsche 924 2.0 N/A (Trackday Project)
- 1979 Porsche 924 2.0 N/A (The other daily)
- 1980 Porsche 931 (Daily)
- 1987 Lamborghini Jalpa
- 1999 Ducati 900SS

[924RACR]

Due to the strength factor, the only way I'd recommend using anything other than the stock belt point for the lap and sub belts is if you have a serious component of the cage structure built down to the floor to accept the mounting of the seat and belts.

If your seat is bolted to the stock mounts - then you have nothing down there as strong as the stock belt mounting points, so use them.

I had a little trouble figuring out what your sketch depicted, I wasn't sure if the rectangle was intended to be the opening in the seat or the adjusters on the belts. If the former, no big deal. If the latter, you need to fix that. I'm guessing the former?

Regarding seat replacement - read your rulebook. The answers are in there. I don't know what rules you're racing under...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[CorsePerVita]