Ok i am just wondering what diameters i will need for my headers and cats w/e. I have the Topspeed exhaust on my car right now and want to put on Strup headers and have a local exhaust shop sell me some pipes to put instead of my cats (they want like 25$ per pipe so 50$ for testpipes basically i guess). My question is what diameter headers do i need and how big do the cats have to be? I noticed alot of the test pipes for sale online are like downpipes, will what this exhaust shop is trying to sell me work? i think they just want to sell me a basic piece of tube lol.




Thanks,

Dan

 

If you are looking to fab your own test pipes, then you will need more than just a couple of pieces of tubing. You'll need 4 flanges and someone who can mandrel (preferred) bend tubing. You will just want to match the piping size to whatever the headers and exhaust are.

 

For headers I don't know how much choice you are going to have. Headers, test pipes and exhaust are within 10mm of one another. If you are shopping forced-induction, and looking for 500 HP plus, then size and matching is important. But for naturally-aspirated, a mismatch is no big deal.

 

well im not going to fab my own test pipes but i just was gonna take the cats off and put a straight pipe there instead. i dont think it needs to be bent or anything does it? just maybe welded to teh Y-pipe and downpipe right?

 

If you want the test pipes to fit then a proper bend is critical. Just buy some decent test pipes for $200.

 

I would also buy a good set of ear plugs.......