Does any one what diameter the door sill bars need to be 1 1/4 0r 1 5/8?

 

First of all, if you're building a 25.5 cert chassis, you should have a copy of the blueprints with all the required specifications. www.sfifoundation.com

My car is not 25.5 spec'd but my sill bars are 1-5/8". According to the NHRA/IHRA rulebooks, the sill bar is 1-5/8". A 25.5 chassis "might" be smaller because of all the extra tubing X'd under the floor but I doubt it.

You don't need a 25.5 certification to run as quick as 8.50. From 7.50 to 8.50 it needs a 25.5 cert. Below 7.50 it needs to be made from CM tubing, TIG welded etc.

 

Thanks I am looking at buying a car to run a 10.5 outlaw class. The guy told me that it would cert to 7.50, but the cill bars are only 1 1/4. You have to run a 5.30 in the 1/8 to be completive.

I find it humors that the whole world keeps the SFI specs so secretive. You should be able to find the basics of the specs without purchasing them. I agree if you are building a car you need a copy.

 

Don't buy a car that "will cert" especially if you need the certification. Buy a car with a current certification. The cost of selling a car can greatly increase if it has a current and valid certification. If it's not certified, the car will be cheaper but there's also a high possibility that it won't pass a cert.

The cost of modifying a car to pass certification can be a lot more than the increased cost of buying a car that already has a certification.