bigger exhaust?

i-wagon

i-wagon

Well-known member
before I spend the money building another catback... is it worth going to a larger diameter exhaust pipe on a n/a? at the moment all I have is a dynomax ultra-flow welded onto the piping from a stock wrx muffler. I was thinking 2.5 inch all the way from the mid-pipe back with dynomax bullet for resonator and ultraflow muffler... input?

 
I've heard that you can lose power by going with too big an exhaust, but I haven't heard anything to back that up (at least not that I understood when I read it).

 
yeah... that's why I figured I'd ask the guru's before I built a $300 exhaust that's worse for the car than what I already had

 
He is right, depending on your mods going bigger then a 2.5"-3" will acctually cause you to lose power.

 
You will lose back pressure. But Most Subaru factory exhaust is very restrictive, so if you go with something like 2.5" you'll be good. There was a huge difference between my RS and other stock RS's. I had headers, and a cat-back on mine, and it was at least 2.5". If you go too big, yes you'll lose power but going a little bigger will be good.

 
I was thinking 2.25 might be good, I have the means to acquire a larger diameter midpipe, and vip has all the stuff i need to build an axleback, and the dynomax I have is 2.25 in the first place, just lots of weld filling the gap;)

i realize larger diameter also means a bit deeper sound. now if only i could find unequal length headers to fit my car.....

 
"ish" that's the problem. headers were made by borla and cheapo companys for rs's till 05. then they changed how the cats mount to the oe headers. so i'd need rs headers and cats and to lengthen my 02 sensor wires. at least, that's the best inski and i could come up with earlier when i harassed him

nate, unequal length makes them sound.....idk boxery. that's why wrx's sound like the secks and mine sounds like honda

 
Right right. Subarus already have unequal length headers, he just wants bigger ones. It's in large part why Subarus have that nice rumble

 
I thought 07s on had equal length headers. I have 2.5in all the way back on my car, there wasnt a huge hp gain, but the butt dyno was off the chart:D

 
I'm pretty sure ALL Subarus have unequal length. Every one I've seen does. But I certainly haven't seen them all.

 
What about my 2.2?
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