Why not just drill a hole right in front of the seat, and put in an eye bolt? An extra piece of metal could be bolted to the underside of the car for additional support if needed.

 

The 6-point harness surprisingly isn't that bad on the nads. I am not sure why -- thinking about it now it does sound painful, but I don't recall any ball trauma from wearing it. The 6-points sub straps are more narrow (2"? 1.5"? can't remember) than the other belts.

It is generally a bad idea to run shoulder straps to the floor, especially right behind the seat. As you tighten them, it will want to shorten your spine, which isn't comfortable and may cause additional injuries in a crash.

-Max

 

This was for the sub strap only, not the shoulder harness.

 

Max is right you don't want run your shoulder belts to the floor right behind your seat. At least for racing purposes. If you get into an accident running the shoulder straps that way, you will compress your spinal cord resulting in serious injury possibly paralyzation. Best place is to mount them in a FD is either where the rear strut bar is or in the trunk foor. A procart racer passed that info on to me.

 

The purpose of the anti-sub belt(s) is the keep the lap belt from riding up which tends to happen as the shoulder harness is tightened. It is not not there to apply pressure to your nads.

In case of a crash, the lap belts holds you in place and keeps your hips from moving forward which avoids trauma to your nads from the sub belt.