Mounting a harness - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Mike_Yi · 11-11-2009, 03:56 PM

I've read a bunch of stuff on how to best mount a harness in a Boxster. Lots of people are vehement about bolting everything you can to the floor rather than to the seat brackets. That makes sense. However, EVERYBODY just wraps the shoulder harnesses around the lower bar of the roll-bar. I'm 6'4" and if I did that, the shoulder harnesses will be sloping up from my shoulders to the roll-bar. If I remove the sliders on my seats (I plan to do this for track days), the upward slope will be more pronounced.

Every installation manual I've seen for harnesses says to mount the shoulder harnesses level with the top of the shoulders, or slightly lower (downward slope).

So if everybody's so insistant on mounting the lap and sub belts correctly, why do are they so careless with the shoulder harness? Has anybody seen a harness guide to ensure the shoulder harnesses are at the correct level? Has anybody bolted them to the firewall (if so, I'd like to see pictures)?

ChrisZang · 11-11-2009, 04:17 PM

Quote:

Originally Posted by Mike_Yi

I've read a bunch of stuff on how to best mount a harness in a Boxster. Lots of people are vehement about bolting everything you can to the floor rather than to the seat brackets. That makes sense. However, EVERYBODY just wraps the shoulder harnesses around the lower bar of the roll-bar. I'm 6'4" and if I did that, the shoulder harnesses will be sloping up from my shoulders to the roll-bar. If I remove the sliders on my seats (I plan to do this for track days), the upward slope will be more pronounced.

Every installation manual I've seen for harnesses says to mount the shoulder harnesses level with the top of the shoulders, or slightly lower (downward slope).

So if everybody's so insistant on mounting the lap and sub belts correctly, why do are they so careless with the shoulder harness? Has anybody seen a harness guide to ensure the shoulder harnesses are at the correct level? Has anybody bolted them to the firewall (if so, I'd like to see pictures)?

Well,

unless you install some SERIOUS hardware you won't find any mount points higher than the roll bar. so the only thing you can do is to lower your seat as much as possible.
If you're 6.4 you must mount your seat directly to the floor (no sliders) otherwise you'll never pass broomstick.
I did that with my seats and I "dropped" around 2 ~ 3 inches

stephen wilson · 11-12-2009, 05:05 AM

Well, it depends on how important safety is to you! How "competitive" are you while tracking the car?

As you've mentioned, the proper installation is spelled out by the manufacturers and racing rule books such as SCCA.

Does the seat you are using have holes for the shoulder belts? Running them to either side of a stock seat is a no-no. The best solution would involve welding sturdy mounts to the roll bar at the proper height. I prefer bolt-in belts over wrap-arounds, which can slide laterally if not restrained, and slip off your shoulder.
Mounts to the firewall would need a sturdy base-plate to prevent pulling thru the sheet metal. The same is tru of mounting the lap and sub belts. Have you checked the Boxster spec site?

Steve

Mike_Yi · 11-12-2009, 08:21 AM

Chris,

The problem I am talking about is the rollbar being too high, not too low. It looks like I need lower mounting points, not higher. A shorter driver would need them even lower.

Steven,

I've looked at the Boxster Spec sites and it's not a problem for them. They remove the factory roll-bar and replace it with a full roll-cage. The can have the cross-brace mounted wherever they want so it will work. I do know that FIA specs prohibit welding or drilling the factory roll-bar. That's why I was thinking about mounting to the firewall. Getting plates welded on would be a huge job though because of where they are. Not sure what I am going to do.

I am using a Recaro Profi SPG XL so that the belts will come out of the seat at shoulder height.

I am only using the car for HPDE, but personally, I don't think that makes a difference. An accident at speed is going to be just as dangerous in an HPDE than in a race. I've got enough back problems that I don't want them made worse in the event of a crash by improperly mounted harnesses. I guess some people can say, "It's just HPDE. It's not that big a deal." But if that's the case, why bother with harnesses at all?

stephen wilson · 11-12-2009, 08:54 AM

You've got a point about modifying the factory roll bar, I'm not sure what type and thickness tubing they use. I'm not sure what structure is in the firewall area you need to mount to, but you may be able to avoid welding by using bolt-in in doubler plates.

I agree, people like to kid themselves that you won't get hurt because it's "just" a DE. Ask the guy on Cornercarvers.com that knocked his wife unconscious when he crashed his Vette!