Exhaust Modifications.

[Bio248]

because the catback does not do anything for performance. there are plenty of guys making 350+ whp on a stock catback.

a 3" catback just makes it loud and wastes money. now a 3" downpipe, that is needed. anything past that is just fine at 2.5".

[blueguy]

In any boosted car (turbo or supercharged) you want the exhaust as free flowing as possible! Im sure the stock mufflers wont flow well. And yes the grand prix will sound really "raspy" without resonators. Maybe look into a full 3" exhaust (more flow the better! And will support more with future mods) a high flow cat and big resonator(s) to some straight through mufflers.

No point wasting money on 2.5" exhaust and wishing you went 3" down the road (then spend more $$$)

Just my 2cents.

Ha. Like Bio says the stock catback flows very well. Hell some dyno runs even show a LOSS of power with a aftermarket catback system. Only time you would need anything like that is if you are running some huge trim turbo setup where 3" is a necessity.

catback does nothing. a 3" is a waste of money.

It just looks good and sounds like poop

How exactly is 3" a waste of money? Care to elaborate?

See my post above

because the catback does not do anything for performance. there are plenty of guys making 350+ whp on a stock catback.

a 3" catback just makes it loud and wastes money. now a 3" downpipe, that is needed. anything past that is just fine at 2.5".

X2.

[SilverGT]

The bigger the exhaust, the better it flows... The better it flows, the more power you make. Simple.

And sorry, I was meaning a full 3" exhaust (including downpipe). Yes a 3" catback would be a waste.

[Bio248]

The bigger the exhaust, the better it flows... The better it flows, the more power you make. Simple.

on a turbo car maybe...bigger isnt always better..

[SilverGT]

My last comment was about boosted cars.

Even though Ive seen RSX's make more HP with a 3" exhaust vs a 2.5" exhaust. It was N/A and he still made a bit more power (10-12whp and torque).

[blueguy]

My last comment was about boosted cars.

Even though Ive seen RSX's make more HP with a 3" exhaust vs a 2.5" exhaust. It was N/A and he still made a bit more power (10-12whp and torque).

Dyno sheets on a 12 WHEEL HORSEPOWER GAIN on a 4 n/a 4 banger...maybe to the crank LOL

Stick with the stock catback. When I installed my 3" System (First big mod after CAI, T-Stat, and plugs) I straightpiped the entire thing and it was just A LOT louder and nope...no faster. Put in a 3" Downpipe/U-Bend Delete...WOW!! Seat in the pants difference.

[02BlueGT]

The bigger the exhaust, the better it flows... The better it flows, the more power you make. Simple.

And sorry, I was meaning a full 3" exhaust (including downpipe). Yes a 3" catback would be a waste.

Um, no, it is about velocity, if bigger was better, we would have 3" primary headers, and 5" cat backs, the stock cat back flows fine, on our local 600+HP whippled 3800, it ran with a stock catback for a little while, now a 3" is on there, unless you are making more than 350WHP, you might as well just burn the money.......


and the Dyno gain on the RSX, peak horsepower isn't what it is all about, sure the car could have gained 12hp at the top, but what about the losses in the middle and the bottom, I'd bet the average HP was lower......