Performance Exhaust

[Sidewinder]

Well recently I've been looking into a performance exhaust and I have a question. Is there any point to getting bigger 2.5" piping? I'm pretty sure the stock size is 2 1/4" which really isn't that much smaller, but is it enough to make a difference?

I'm worried that by going to bigger piping that I will loose low end power, which I don't want. So what do you guys think?

I'm going for dual mufflers, high flow cat, custom downpipe, and should I toast the resonator?

[Azrael]

Go with 2.5" if your plans will take you over 200BHP in the future. You'll have to lose the resonator if you want to benefit from a highflow cat and downpipe. No sense going back to stock diameter inlet/outlet of the oem resonator after those. However, going without a resonator might irritate you with the "highway drone". If you find it's too much you can always throw on a bullet-style muffler in it's place. Avoid using cherrybomb-type glasspacks for this as they're usually restrictive. I had a 2.5" one that actually closed down to 1.9" internally.

[IsaacHayes]

Ditch the resonator. The way they are made it's a big disruption in flow. I didn't notice any extra loudness when I got rid of mine like I was expecting, just some welcomed power actually! They open up big, then has a flat washer with a hole that the exhaust will slam into and have to go out. It's not tapered or smooth at all.

Also speaking of that if you want power go with a straight through muffler not one like flowmaster.

I only had drone with my ultraflo when it didn't have a tail pipe on it and opened up under the trunk. Now that I have my tail pipe and Z26 tips back on, there is no drone.

[Sidewinder]

I also hear that there is a U-Bend in the exhaust (not sure if this applies to my car) that causes a restriction, and that I should remove it. I was told to look at the zzp website and that they have downpipes. Edit: I went and looked at them, and it will cost me $179.99US from them to remove these restrictions, assuming their downpipe would actually work in my car and with the 3100.

As for the piping size, I've heard that 2.5" will cause me to loose low end power, but I've also heard that getting the bigger piping will help increase performance. I do mostly city driving, so for me low end power is where its at so I don't want to loose that.

As for the brand, I'm going with Magnaflow for the mufflers and the cat.

[IsaacHayes]

Not sure if you have the U-bend or not. The U-bend is where your 2nd O2 sensor is that reads to make sure your cat is working for emissions. So look there and see what you have. If you are getting down pipe back then it'll be replaced anyways.

Not sure if 2.5" will cause you to loose any low end.