i installed my strup test pipes, with nismo y pipe and stillen exhaust and it seems like after 3k i have a rasp.

Went thru the whole thing again and put in new gaskets and sealed them and i still have it...

what could your thought be?

 

Rasp is common with test pipes. If you're set on the setup you have, then the only option is to get some good resonated test pipes. Tony @ Motordyne is currently working on a set of resonated test pipes that should be out in a couple weeks. If you simply can't wait that long, then go with Fast Intentions' resonated test pipes.

 

Thats completely normal.

Your best bet is to get some properly resonated test pipes (as stated above) or just go with some high-flow cats.

I have a similar set-up using Stillen Gen2 exhaust and am running Fast Intentions HFCs with excellent results. No rasp. Also my car is dynoeing at 416rwhp now and i don't think using Test pipes would really improve on this.