So the Jdm itr has the 4-1 header with a 2.5 collector that connects to a 2.5in-2.25out cat with 2.25 exhaust piping. Wouldn't that create backpressure or whatever? Would that affect performance at all? The reason why I'm asking is because that is how my exhaust is setup right now.

 

Just wondering if the setup with 2.5 header, 2.5in-2.25out cat, and 2.25 exhaust piping create any problem performance wise.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by djtony5 &raquo;</TD></TR><TR><TD CLASS="quote">Just wondering if the setup with 2.5 header, 2.5in-2.25out cat, and 2.25 exhaust piping create any problem performance wise.</TD></TR></TABLE>


Didn't for me, although I subbed a Spoon header for the JDM and ran OEM catback.

In all honesty, even when I subbed a 60mm OD catback and N1 muff for the stock catback I didn't really notice anything till about 7,800 rpm. On track where you're always above 5k I noticed a more free feeling, and didn't feel as stifled at redline, as in it felt like it would keep pulling as opposed to the stock setup. But this is "Feel" with No data to back it up. It could be totally placebo.

There are limitations to the USDM and JDM stock setups besides just shrinking diameter as it moves aft, IE bottleneck at second resonator.