[eggman51]

Originally Posted by Vanne

My take on the whole thing is regardless of the rules, youd have to ask yourself a question. Is it a good idea to run 4/6 points with out a roll bar, pretty sure the answer to that is a definite no.

This is where I am sot sure I understand all the safety related issues. If it's OK to run a convertible with factory roll hoops (as some groups have determined) - then I don't understand how 6 point harnesses or fixed back seats make it any less safe.

It seems to me that if you are going over, the type of seat or seat belt has nothing to do with safety, it's over to physics and geometry that would be constant regardless of seat or harness type.

Originally Posted by Vanne

Eamonn, if needed mate, I can send you pics of how I went about it, I'll need to dig em up or take some new ones. Car is under 3 tarps ATM, hiding from the heat/sunlight.

Don't put yourself out, but if you have some pics handy that are not already posted, they would likely be helpful. I am pretty sure I will end up mounting my harness the same way you did yours - strongly reinforced into the bulkhead, at the correct height, but not directly mounted onto a roll bar.

I will probably end up putting a roll bar into this car, but I need to do more research on a roll bar configuration that preserves the soft top. Based on the earlier post in this thread it can be done! Have reached out to that owner through the interwebz, but no response just yet.

Originally Posted by 3002 tii

This thread has got me thinking if our factory roll hoops could serve as a roll bar that's required for harnesses but maybe the trick is to run non-fixed back seats. In that case maybe I can run a Profi II ASM FE's (DOT legal, anti-submarining tech, HANS compatible) with seats similar to this owner.

Still not sure I understand the relationship between seat type and safety - I must be missing something (not being sarcastic there) - I just don't understand how fixed back vs reclining has anything to do with safety?

In the linked thread above, the angle on the shoulder straps would not conform to best practices for mounting a harness. The shoulder straps should be flat, or angled down up to 25 degrees, but not angled up.

The seats in the M - lovely for spirited road driving - are not usable with a harness because of the fixed headrest (and they do not have a hole for anti-sub straps, so afaik can only be used safely with the Schroth ASM capable 4 point belts). However, they should still follow the guidelines for mounting positions and angles.

I notice the owner of that car said he would use the 4 point harness for Autocross, and the 3 point belt for track and daily driving. Not sure I understand why unless it's a governing body / approval issue.

Originally Posted by 3002 tii

And then use eyebolt back plates welded to bulkhead, nice and clean like this. Entire setup is basically 95% reversible, not too crazy of hit on wallet doesn't appear to compromise safety. I may reach out to HMS to get their take...

This is what I am planning to do, and appears to be how Vanne mounted his shoulder straps behind the fixed back racing seat. I just ordered the parts for this from HMS.

I am going to use a "proper" race seat - a Sparco QRT Performance - and a Schroth 6 point harness with Brey Krause mounting hardware and mount the shoulder straps into the rear bulkhead with Schroth FIA approved re-enforcing plates on the back side. I will mount these in a way that conforms to harness mounting guidelines.

I believe this should be as safe as any roadster with factory roll hoops, and should provide a much better seating arrangement for track driving (which I could argue improves safety).

Totally open to the idea that I may be missing something, this is safety so I am not wanting to mess about, but I can't get a roll bar into the car yet. However, I don't see the relationship between racing seats, 6 point harnesses, and factory roll hoops being less safe than factory seats, 3 point belts, and factory roll hoops.

Cheers,
Eamonn