yep, i was just going to say the 60-70mm test pipe/ resonated test pipe. i believe asura offers it and possibly berk.

 

like someone mentioned earlier........has anyone ever compared 60mm-->70mm and 70mm-->70mm???

because the collector of the header is NOT going to be anywhere near 60mm for the stock exh manifold, so would 47mm(ish?)-->70mm flow more air than 47mm(ish?)-->60mm-->70mm??

also keep in mind that the temperature of the exhaust pulses will be getting cooler as they get further from the engine, so the exhaust pulses will decrease in volume.

just throwing that out there, im curious on the actual results. but bigger is not always better...

 

If I am using stock header and stock exhaust, is there benefit to use 70mm HFC versus the 63.5mm HFC ? I don't know what the stock header and exhaust pipes are and curious if there is fitting issue with 70mm.

Thanks.
Frank

 

thinking of ordering the Tanabe Medalian Exhaust...would it be a problem using a 70mm test pipe? thining of ordering this pipe



http://www.ebay.com/itm/Honda-S2000-...RZm&vxp=mtring

 

2009 bruh...






always try to match the diameter. but search a newer thread, might answer your question.

 

Very bad idea, always always want to keep the same diameter, just order a 60mm test pipe, they're cheep

 

I'm convinced -- but can't adequately articulate why -- a large diameter catalytic converter or (wink, nudge) test pipe is detrimental to exhaust performance in other than a completely engineered system stretching from the engine to rear bumper.

In the case of my '06 S2000 with a stock exhaust manifold I'm using the 63.5mm Berk high flow catalytic converter and Tanabe Medalion Touring dual exhaust. Pretty much constant diameter system. Dynoed at 221 wheel horsepower on a conservative (?) Mustang dyno after a tune. (But no "before" data.)

-- Chuck

 

Match the collector, not the cat back.

 

The test pipe size will make absolutely zero difference unless the outlet of the exhaust manifold is larger than 60mm. Period.

 

Its not long enough then. You need to add another extension to pull the sensor further out of the stream. Ebay sells these for like $10. Just make sure its for Honda/1.5mm thread pitch. I had to double stack mine because the Birk one with built in extension it came with was not designed very effective.