I have been looking at a cat-back exhaust from Cobb Tuning (bolt-on) for roughly $500.00 Will you really get some horsepower and torque boost from this mod? If so, how much? I have emailed Cobb with this question and haven't heard back, yet.
i asked the same thing on I-club and the concensus was that a catback exhaust was just a sound mod, comparable to that of installing a BOV. if i were to go with a catback exhaust, i would go with a scoobysport piece from http://www.rallyperformance.com since you can later on add the mid pipe and down pipe, in the process of killing a couple cats . i'm not sure if you can do that with the cobb piece, but if it's possbible i don't see why not to get a catback.
I'm not sure what the gains are, but I have to say I've gained something from my cat-back... I installed a Stromung 2.5 inch mid-pipe, with a 3" exhaust... .and it really seems to help spool up the turbo quicker.....plus stromung is making a downpipe also..... check them out... Stromung
A Cat-back exhaust is an exhaust from the end of the cats to the tip of the exhaust. So it does not touch the cats. Gains will be minimal because the set of 3 cats are the real restriction in the system -- you don't open a drain by reaming out the section after the blockage right?
A turbo back exhaust, however, would potentially remove the cats, and gains there could be substantial, particularly if one increases boost as well.
Guys, thanks for the responses. I figure the CATS were the bottleneck, but I am still learning "mechanical technology" if you know what I mean (i.e. I am lacking on the mechanical side, ha). Thanks again.