'84 2+2 test pipe?

[FreeLanceBum]

http://www.certifiedmuffler.com

[EEMz31]

just out of curiosity is there any power difference between the test pipe and a high flow cat.

[Dan-TSS]

I don't recall seeing anyone posting back to back runs showing the gains/losses on a z31.
*It is fact, that the gains are very small when swapping from a std. cat to a high flow cat. converter.
**It is also fact, that cars in modified trim, typically see a gain of ONLY 4-5% in Hp. from using a test pipe instead of any cat. converter.

Dan

[Jason84NA2T]

A long time ago someone dynoed an 8hp difference on a NA car with an existing aftermarket cat-back exhaust.

The cat is the same length on 2 seat and 2+2 models. Only the length of the piping behind the cat is different, by about 8 inches. You can either extend your test pipe or put another small section of pipe with two MORE flanges behind it.

[Gritt]

i agree the flow-ness of a stock cat is probably not that restrictive, however a "22 year old" stock cat is not going to be flowing like it used`ta could.