bruinbro

I figured I would re-hash this topic one more time as i need to figure out what to do with my harnesses.

A little background: I have a 2000 Boxster S with Sparco Evo2 seats mounted to Brey-Krause steel brackets which in turn are mounted to Porsche GT3 sliders.





The harnesses are TeamTech 6-point RamPac belts.



The Stable Energies cage provides a built in harness bar for the shoulder harnesses.



The B-K seat mount provides a built in threaded boss for mountin the stock belt receptacle and a B-K lap belt anchor. The Sparco seat has a slot cut into the seat bottom to accomodate what I believe is a single sub-belt as the width of the slot does not allow a big enough spread for 2 sub-belts. The sub-belts are not very long.

My car is a daily driver and although it will see a lot of DE track time, it might not see any TT events and most likely will not be converted into a race car. How should the sub-belts (and lap belts for that matter) be mounted? I would like to be able to accomodate different drivers from large to small.

Thanks,

Bro

RedlineMan

Of course, Bro;

You're on the slope, and grip is going away fast!

Point - Since you won't likely race it, you don't have to worry that most race groups will not allow a belt to mount to a seat bracket. They have to mount to the chassis directly.

- If you want a sub to always be in proper adjustment for many size drivers, it needs to mount to the seat. Again, most race groups don't allow this, but for DE it makes a lot of sense to me. I do it regularly. The Schroth subs (both Hybrid & Profi) are the only ones I know with slide adjusters, but even they are not long enough for extremes of adjustment. They probably will work for most driver combos, though.

- The easiest and most comfortable way to mount your "V" sub will be at a single point, utilizing it like a single sub strap. Mounting them as a double down under the seat offers no advantage over a single sub.

- You can create a cradle setup by mounting the sub to the lap belt points and sitting on it. This is the least comfortable way to wear a sub, as it must be worn fairly snuggly to be most effective, but also the most effective in terms of hip control and safety. But, if you hit something, you will go castrati quite quickly.

- If you can find a "T" sub (where is space between the straps for "the kids") that will properly clip into your latch, then I would cut the dual seat holes in the base, and mount the sub to the seat bottom so as to configure the "split" sub properly. This can be very effective in both safety AND comfort.

All very tricky.

Larry Herman

Bro, I had this setup in my GT3. What I did was to use the BK sub bracket that bolts under the seat. I drilled holes as wide as possible and installed eye bolts and clipped the sub belts to that. It didn't leave a whole lot of room for the "boys" but it does mount them at the right angle to work properly.

BTW John, I bought the Team Tech Jet Pilot 7 point setup for the race car. That is a system that you'd approve of. It mounts in the traditional 5 places and then it has 2 slings that wrap around both legs in the crotch area, and a belt that wraps around your lower back, just like a parachute. When it is buckled properly, it prevents any forward motion, and you cannot even feel the "sub belt" that runs down through the seat. I love that way you feel locked in place.

onasled

Larry Herman

I'll beat John to the punch here. If the sub belt runs forward from where it buckles down through the seat, then you will definitely slide forward in to the sub belt in a frontal impact. Not the best setup.

onasled

Not sure you are addressing my photos ...
If so, that slot was custom made for my fit in that seat. Its just slightly under manlyness...

bruinbro

Thanks for the thoughts so far, keep 'em coming!

Would it make sense to run the sub belts out the lap belt hole as John had mentioned and then bolt them to the seat bracket? Or, what about widening the slot in the seat? Or creating new slots in the seat? I like the idea of utilizing the subs as a cradle, it's just that the seat openings don't work well with that idea.

Bro

38D

Looks to me like this will put major stress on the hole where the sub passes thru the seat.

onasled

Remember, this is DE we are discussing, so in no way would I recommend this for racing, not to mention it's not legal.
The stress issue was discussed and we came away feeling that for DEs this would be fine.

onasled

IMHO, No, it would not be a good idea to run the sub straps under your thighs to the lap belt slots. Bad idea. Just use your sub slot that came on the seat and run them like in my picture, IF this is just for DEs.

Capt. Carrera

Your best option is to mount them to the same points as the lap belts as mentioned earlier. This setup is hardly a bad idea. It's simple, and it's safe. In fact, sitting on the sub belts is detailed in the SCCA GCR as a proper way to mount the subs. (you can download the GCR for free at ww.scca.org. Just do a search for 'GCR' at the main page.)

Your choice is really quite simple. You can either copy one of the plethora of kludged-up installs readably available on the Internet, or you can use an install that will pass SCCA race tech. Which do you think would be a better?

Capt. Carrera

Onasled,

Is it possible to get those adjuster plates closer to the mounting tabs on your subs? In an accident, the plates usually slide until they hit the mounts. In other words, your subs will lengthen to whatever gap you have, plus 15% to 20% for belt stretch, provided the seat does not cut the belts, or the belts don't tear the seat.

It's always a good practice test-mount belts at the stretched length. Simply measure all your belts, add 20%, and reinstall. Belting in at the stretched lengths can be quite revealing.

RedlineMan

Yes Larry, good point, and mind well read.
--------------------------------------------------
As onasled said;

DE is a bit different. Gives you a bit of latitude because speeds and chances taken reduce the likelihood of a crash. Dual purpose/multi driver use requires more compromise. The stress-on-the-seat idea is not to be dismissed, but is probably not that great from a sub strap. I mounted a single sub to the bottom of an alloy seat that a buddy crashed at approximately 40-50mph at the Glen (t-boned a car that lost it in front of him). The seat did bend around the hole, but not to a significant degree. The car was an ENTIRELY different matter!!!

I'm not sure if I would worry more about the seat, or the belt. This type of mounting does create a stress point for the belt. To mitigate that, I recently came up with this setup for Schroth Hybrids in a Club Race 944. The belt bends more gradually over the tube apparatus instead of sharply over the seat base.



The onasled setup puzzles me in that running the belt through a single hole completely eliminates the comfort advantage of the t-bar sub. That sub does not look like it offers a lot of seperation in the belts to begin with, but it would have to offer some ball room over a single or V sub. ????

RedlineMan

Hmmm....

I must respectfully decline to agree, as this in incorrect.

The sub does one thing; controls the hips. Any single does this by keeping the lap belt low. The lower the lap belt, the less mass below it to project forward. This is passive hip control.

A double sub can be arranged as a cradle, tails mounted rearward, to provide active direct hip control. If you are talking a V sub, this is the best arrangement. It must be worn tight for quick take up. This is not comfortable, but it provides the best hip control, directly. Otherwise, it is no different than a single sub.

Comfort is the reasoning behind the T sub. The subsequent Schroth Hybrid gives the best comfort and hip control in one.

RedlineMan

This is a good general point;

3-bar sliders will indeed do just that until all the slack in the loop around the mount point is taken up. I have never seen any numbers on the difference in stress levels between the main belts and sub. Lap belts see 25-2800lbs in an "average" 30-40g hit, while shoulders see 1500-ish each. The sub sees far less stress, and I don't think it will see enough to slip the 3-bar sliders, but there is also no sense taking any chance, as it is easy to adjust them with no loop at the mount.

The adjustment at 10-20% is also an interesting idea to illustrate for folks how there are things they WILL be hitting with their heads even if strapped in. Most people simply have no clue.