I'm going to be building a 8.5 cage for my drag car. The NHRA rule book doesn't state anything about spec on the 4130 tubing. I've purchased some Cold Drawn 4130N tubing from the local tubing supplier. Recently I've been reading about MIL spec tubing being required by SFI for chassis cars. Is it required on an 8.5 cage?

Regards,
Justin

 

sfi foundation

 

I have the SFI 25.2 chassis spec here. I've read it over. The thing is, all SFI chassis specs are for 8.49 and faster. I'm interested in a 8.50 and slower cage. Does an 8.50 and slower cage need Mil spec 4130N?

The NHRA rule book makes no mention of the 4130 requirements so I'm a bit confused.

Regards,
Justin

 

I'm not sure if it says it, but it must be in the "n" conditon, yes.
4130 N is perfect, and as long as it's .083", you are fine.
That will get you to 8.50 and 149.9mph.

 

oh whoops, sorry about that, i thought you were talking about building a cage for 8.50 and faster.