Nissan 370Z Forum - View Single Post - RobiSpec Harness Bar

1slow370 · 11-13-2014, 04:21 PM

Let me just put it this way, a harness bar needs to be able to support at least 24000 joules of impact force in a low speed collision or the equivalent of tying a rope attached the bar to 260kg weight and dropping it 9.4 meters. That would do for street duty.

in a racing situation we can increase that to 66,250 joules or the same weight dropped from 260Meters.

Edit: another thing to remember is that the factory belt location is designed to work with pretensioning belts so the impact force at the mount point is lower due to the longer time of impact as your body move against the belt, rigid belts will transfer more force to the mount bolts due to the decreased transfer time. Also the energy figures I posted are somewhat exaggerated as they assume a dead stop like if the car hit a wall head on and there is more that goes into it than that because if you hit side ways there will be less force on the bar but it would all be on one mount.

11-13-2014, 04:21 PM	#37 (permalink)
1slow370 A True Z Fanatic Join Date: Aug 2009 Location: In the D Posts: 3,732 Drives: v8 74 260z ;) Rep Power: 7251	Let me just put it this way, a harness bar needs to be able to support at least 24000 joules of impact force in a low speed collision or the equivalent of tying a rope attached the bar to 260kg weight and dropping it 9.4 meters. That would do for street duty. in a racing situation we can increase that to 66,250 joules or the same weight dropped from 260Meters. Edit: another thing to remember is that the factory belt location is designed to work with pretensioning belts so the impact force at the mount point is lower due to the longer time of impact as your body move against the belt, rigid belts will transfer more force to the mount bolts due to the decreased transfer time. Also the energy figures I posted are somewhat exaggerated as they assume a dead stop like if the car hit a wall head on and there is more that goes into it than that because if you hit side ways there will be less force on the bar but it would all be on one mount. __________________ ANSWER PRICE LIST Answers - - - - - - - - - - - - - - - - $0.75 Answers (requiring thought) - - - - $1.25 Answers (correct) - - - - - - - - - - $12.50 Last edited by 1slow370; 11-13-2014 at 04:32 PM.