370Z Harness Bar

BGTV8

I had quite a discussion with Brenton (the principal of Meridian Motorsport) who by the way is a mechanical engineer by trade and a long time racer in Sports/1300 (C and D Sports Racing is the clostest US equivalent) and a guy whose professional opinion I respect.

His view is that the shock loads in an accident imply a 100kg load (eg: me and my fat arse) at 8G (on the basis that a greater than 8g load will rupture my aorta or spleen which is a bit terminal ) is sufficient to bend anything that is indirectly attached, or attached in a manner that permits a bending load moment - either as a straight pull or as a twisting/rotational moment). If you exploit one of the options shown in the website reference, you will certainly have a bending or twisting moment of some kind.

The only option I can now see (having pondered on this some overnight) is that it might be possible to fabricate something out of RHS (rectangular hollow section if you are not familair with the term) that can be bolted to the floor using the two bolts that fix the rear of the seat runners to the floor, and then to fix a pair of eye-bolts to the RHS. The minimum requirement would be 3mm wall-thickness mild steel and I suspect that you would need at least 40mm RHS to get sufficient clearance.

I have roughed up a "drawing" (I am not a draughtsman, so it is "Very" rough) to try to convey what I mean. This would certainly permit you to avoid drilling the bodywork or plastic trim, and could be an option.

My drawing shows the eye-bolts mounted inboard of the seat rail mounting bolts, and option would be to mount them outboard, but you would want to ensure that there was space betwen the tunnel and the drivers door sill to make the mounting wide enough to provide sufficient material to generate the required strength to resist the loads implied in an accident, and that is not my forte.

If you have a local machine shop (or maybe one of the suppliers on the forum may pick this up), you should be able to get some calculations done on the amount of material around the eye-bolt that is required and then determine whether the approach I've outlined might work. For me, I'd be a tad concerned that the options shown on the website reference could resist the sorts of twisting/bending loads implied in a big shunt .... and having been thru a 130mph hit into an armco barrier in my race car 10 years ago, having belts that are solid and secure is for me, a priority. I have even re-engineered my race car to make the should belts as short as I can to avoid belt stretch providing too much freedom in an accident ..... a "big shunt" certainly gives you motivation in this regard !!!

Rgds

RB

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