I want to get a magnaflow aftermarket muffler w/no piping changes but I can't make up my mind to go with the 2.0 or 2.25. I was wondering if there is even going to be some sort of performance increase with both? I'm also replacing the cat.

 

Won't make a difference if all you're replacing is the muffler.

 

2.25 and change ur piping

 

I just bought the cat-back at 2.25". You wont lose as much backpressure as say a 2.5" but 2.25 can still be used for turbo (which I plan on).

As Amby said. If all your chaning is the muffler it doesnt really matter. You wont notice any gain. With sri and 2.25" cat-back I have a wincy incy bit more pull in top end but thats it. Lot more noise is what you will get.

 

Well i'm also replacing the cat w/a high flow one so ill have a bit more air coming through and im doing sri. But since the magnaflow muffler is a lot more high flow than the stock and it's 1/8 bigger than I would think that would be enough, especially to keep backpressure. But I'm not sure. I want a deep tone. No rice and as much performance. If 2.25 will give that to me than that's cool. I don't want a cat back though. I just want some sound.

 

You never fail to contradict yourself.

 

? Ok so all you want is sound? If that's the case just buy whichever muffler is cheaper and call it a day. If you want performance, you'll have to go catback, just doing a muffler is useless performance wise. All you're doing is opening up the exhaust at the most distal end, all the gas still has to squeeze through the tiny stock piping.

 

ok im convinced, b/c all the small piping it wont make a diff. but let me ask a question does anyone believe http://www.magnaflow.com/02product/dynos/15805.jpg b/c if it's true i think im gonna wait awhile longer and get that catback with a high flow cat. but it's still gonna be 420 bucks. Has anyone felt gains that somewhat resemble that dyno? Thanks

 

well the piping isnt tiny, but all the bends and cats and carbon buildup is what restricts it, but you might as well go with the 2.25 cuz thats what the stock piping is, my muffler is 2.5, i just have a weld on, im waiting to turbo it then im making a custom full exhaust

 

Stock piping isn't 2.25", it's maybe 2" at the very most, I've heard it's as little as 1 3/8". If you actually look at the stock exhaust there aren't a lot of bends, it's almost straight back from the cat except for a hump to go over the sway bar. That dyno is crap, there is no way an exhaust gave a 10 hp increase on a stock engine. Most people don't even notice any difference with an exhaust, just more noise and, in some cases like mine, better gas mileage.

 

how much better gas milege did you get? so basically its not worth 400 bucks. so i should go w/a 2.0 muffler and a high flow cat. are you sure it wont give that kind of dyno?

 

Buschur Racing's 2.5"(no longer in production) catback with only one muffler only added peak 2whp and 3wtq with gains of 7-8whp on parts of the graph. magnaflow is BS. it was probably the lightest, straightest mandrel-bent catback that was made for our car.

 

My gas mileage went from about 450 km to a tank to over 600 km to a tank. I never said it wasn't worth it, I simply said you won't get 10 hp on a stock engine. It all depends on what you want. If you want performance and plan on modding the car further (maybe turbo down the road) go for a catback system, either the magnaflow or the greddy. If all you want is sound and looks, save your money and just get a nice muffler.

 

well since we are talking about exhaust.. i know someone who has header with 2.25 piping.. he saids he feels a loss of power and doesnt recommend it. He told me to put the headers and kill the cat , stock exhaust and put the raliiart muffler. he said i should have better gains. I was doing research about this but i would like to know ur guys opinion. I told him bout me putting 2 inch piping but he suggested to stay with stock exhaust.

 

If you open the exhaust up too much too early, you'll experience a loss of low end power due to the loss of backpressure. The best plan in my opinion is for every exhaust mod you do do an intake side mod. The exact route I went is intake, header, throttle body, intake manifold, fuel rail and then catback exhaust and I haven't noticed any loss, only gains. Unless you're turbo I wouldn't recommend changing out the cat, in the recent Import Tuner they did a comparison between stock cat, two forms of a high flow cat and a test pipe and they gained maybe 3 hp out of changing out the cat, and this was on a 160 hp engine. On our engine you'd be lucky to gain 2 hp.