I know it's 11.49 in the quarter mile, but what about the 1/8 mile? I don't recall seeing any mention of 1/8 mile in the rule book. What conversion factor (1/8-1/4) does the NHRA use? Different sources seem to use slightly different numbers for converting.

thanks
codfish

IIRC 7.35 in the 1/8.

I think you right 7.35 in the 1/8th.

havent they changed it to faster than 11.00?
That would be around 7.0 in the 1/8

you might be right..

10.99 and 6.99 are the when you are required to have a cage versus the bar.

7.50 for the roll bar in the 1/8th.

I can tell you my last time out I ran 11.55 with a 1.59 sixty and the 1/8 was a 7.30. Ron

My best so far, at the airport races here, was 7.31@96 MPH. Hoping to better that a little next weekend.

But in 4 weeks I'm going to a real track. With the last combo (360/904 and 4.57s), I picked up three tenths by going to a track versus the airport. NO changes what so ever.

With the new combo (stroked RB, 727, and dana with 3.73s), I hope to pick up at least the same.

thanks
codfish

rulebook says 9.99 and quicker you need a cage.
Tech here in sweden says 10.99 and quicker you need a bar.

Rulebook actually states cage must be certified at 9.99 or quicker. Cage required at 10.99 unless all the original floor and firewall is in place excluding wheel tubs.
Here is the actual verbage and the answer to the original question is 7.49

4.5 ROLL BAR

Roll bar mandatory in all cars running 11.00 (*7.00) to 11.99 (*7.49) and in convertibles running 11.00 (*7.00) to 13.99 (*8.59), and in dune-buggy type vehicles running 12.00 (*7.50) seconds and slower. Permitted in all cars. See General Regulations 4.10, 10.6.

4.6 ROLL CAGE

Roll cage mandatory in cars running 10.99 (*6.99) or quicker, or any car exceeding 135 mph (217.2 km/h). Full bodied cars, with unaltered firewall, floor and body (from firewall rearward, wheeltubs permitted), running between 10.00 (*6.40) and 10.99 (*6.99) roll bar permitted in place of roll cage. Cars running between 7.50 (*4.50) and 9.99 (*6.39) must have chassis inspected every three-years by the ASN and have a serialised sticker affixed to cage before participation. Must conform to specs for body style used, as listed in General Regulations 4.11, 10.6.

Darn it Eric, I liked the sound of 7.35 better! Was it maybe 7.35 a couple years ago?

Full bodied cars, with unaltered firewall, floor and body (from firewall rearward, wheeltubs permitted), running between 10.00 (*6.40) and 10.99 (*6.99) roll bar permitted in place of roll cage.

Does that meen that you dont need anything running slower than 10.99 or 6.99?