Kyushin

I have an AP2 CT exhaust and was wondering what TP or Cat would be best, I really wanna go with a highflow cat. Would the Asura or Berk 70MM highflowcat give some gains? Im also supercharged!

Swiftoy

I don't think the Comptech is a 70mm exhaust so I would look into matching your HFC or TP size to your exhaust at either 60mm or 63mm. If you live in California the HFC is still illegal. I thought about doing the HFC after the TP I had, it made my exhaust sound terribly raspy. I just recently put on the T1R resonated TP since Im in California they are both illegal an no raspy exhaust anymore. Some have said the T1R sits a little low if you are lowered it MAY scrape espacially if your slammed.

Kyushin

The CT exhaust is definitely a 63.5mm pipe diameter which I confirmed with CT Engineering this morning.

it'S2klean

Test pipe or HFC will really make your exhaust gains shines. Gernby has a mega thread on it, but in general, they perform the same (TP or HFC) its the sizing that matters. In general test pipes are more raspy than HFC

I would get berk HFC

Swiftoy

If you have a tuning solution such as flashpro or an AEM ems you WILL see better gains with a standard non resonated TP over the HFC. It is very hard to get VTEC down below 5400rpms with the HFC or resonated TP. I was running the toda refalsh with the standard TP and the gains were significant(vtec 4100). I am in the process of an E-Tune right now and the only thing I changed was going to a resonated TP and my VTEC engagement point is now at 5400. Car doesnt like it.

it'S2klean

Really.... im glad you braught that up, because i am actually running a TP right now with AEM and my vtec is set at 4,100 around there, and i was planning to get the q300 with HFC since it picks up rasp with a TP so it looks like ill have to wait until an exhaust i have my eye on is gunna be released.

Swiftoy

Actually if you keep with what you are planning to do and add a header this will allow to drop the vtec engagement down lower possibly even lower than 4100 rpm,s. Go back through and read Gernby's post the whole thing if you can find the time. The resonance created by the CAT, HFC or resonated TP is the limiting factor in lowering VTEC it is not necessarily flow that is the issue.

I attached Gernby's thread.

https://www.s2ki.com/s2000/topic/842...test+pipe+test

Kyushin

Looks like the berk HFC is the way to go, then header will be the last bolt on. The header is already decided on, I love the looks and numbers of the FF headers.