Originally Posted by prostcelica
Hello guys. Can I run a 5 point harness with this style of seat? Car will probably run low to mid 11's. I don't want to get to the track and have the tech inspector to say.
I also want it to be safe.
Down to and including 11.50 seconds E.T. in the quarter mile (about 7.37 in the eighth mile), a racer can run with a stock lap belt/shoulder belt system and any kind of OEM or aftermarket seat, bench or bucket, that is secured to the car. This assumes that the racer has enough sense not to use an unreinforced plastic/poly kitchen chair.
At 11.49, the racer must install a minimum 1 3/4" diameter, minimum 5-point rollbar (not to be confused with rollcage, which becomes necessary at 9.99 and can use smaller 1 5/8" tubing). He can still use any OEM or aftermarket seat that he wants to, as long as it is properly secured to the car. At 11.49 and quicker, the racer must install an SFI-approved 16.1 seat/shoulder/crotch belt arrangement. If the racer uses a stock OEM seat, the crotch belt may be routed around the front of the seat. If using an aftermarket seat, the belt must come up through the seat bottom in the vacinity of the driver's gonads. In either event, the belt must be anchored behind the center of the driver's chestline.
I have gigged several thousand racers for this violation, anchoring the crotch belt out if front of the seat where it will do absolutely no good from a protection standpoint. When installing the belts, driver should sit in the seat and mark a place directly under the driver's gonads as the anchor point for the crotch strap. Do not install the crotch strap any further forward than this point.
If you are anchoring the crotch belt through sheet metal, install a large (like 3" diameter), thick flat washer on the bottom of the floor to prevent the connection from pulling through the sheet metal. If the tech inspector is worth a damn, he will be looking for this large flat washer.
Reading through this wiki tutorial that I wrote several years ago will help you to understand the geometry involved.....
Scroll down here to Section 20, page 18, where the section 4:10, Rollbar begins and read through the section thoroughly. Some of the verbage may have changed between the time I wrote the wiki article and this 2012 NHRA Rulebook link......
Here's an 1/8 mile to 1/4 mile E.T. conversion that may help some.....
Eighth-to-Quarter Drag Racing Times