Right now on my GSR im running the JDM ITR 4-1 with carsound high flow 2.5 to 60mm Apexi N1 cat back. My Cat back is now leaking at the axle back connection and the back of the muffler is corroided and leaking also. Oddly threw all this the car seems to perform alot better. Can this mean that before the exhaust started leaking that the bottle neck effect of the 2.5 to 2.3 was holding back power potential?. Would it be wise to just go ahead now and upgrade to a 2.5 cat back to maybe expect better gains than the 2.3?

 

bump

 

Well the 2 1/2 in to 60 mm would cause a slight bottleneck. But are you sure that is actually performing better, or is it just the additional (horrid) sound of the leaking exhaust making you think it's faster? It's like everyone throwing hot-air intakes on saying their cars are a LOT faster, when really it added little if no power and the sound is all they're "feeling".

Anyway, back on topic, if you have a 2.5" header and cat, why not upgrade to 2.5" cat-back? Seems logical to me.

 

i agree with 91tegls. i doubt you are getting any kind of performance difference. besides, the butt dyno is hardly reliable. as far as getting a new exhaust goes, what were you thinking of dong besides getting a 2.5 exhaust? another thing, jdm itr exhaust is 2.36", not 2.5

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BuyImports2 &raquo;</TD></TR><TR><TD CLASS="quote">i agree with 91tegls. i doubt you are getting any kind of performance difference. besides, the butt dyno is hardly reliable. as far as getting a new exhaust goes, what were you thinking of dong besides getting a 2.5 exhaust? another thing, jdm itr exhaust is 2.36", not 2.5</TD></TR></TABLE>

I was going to go wit a 2.5 cat back from KTeller

 

bump

 

why did you bump? what hasn't been answered?

 

Yes, you will feel a difference. Your topend will feel slightly sufficated. I went from Apex N1 to a Spoon n1 and the Spoon N1 has a bottle neck and I did feel it. Since then I've had it cut out, the resonator removed from the b pipe and it sounds AWESOME and power is like it was before... Soon, Ill get a catsound and call it good.

 

well I went to the trackyesterday,. The car didnt run any faster than my normal fatest time, but there was little improvement in my MPH which means that there is a little more flow in my top end. So now im going to go ahead and prepare to order a resenatorless 2.5 cat back and see what that does.