i have an apexi n1 muffler and i was wondering if i should do 2.5 or 3 inch piping and take out the cat or leave it on its no good anyways it smells bad and the car also has headers and its goin in the shop on fri. so your guys input will help thanks

 

3" will be all gains, but the 2.5 will be a lot quieter with possibly *no* performance difference (some find a better top end with a 3, but there`s a chance that your midrange will flow better with the 2.5. it`s alot easier to run a 3 below 3000 after you`ve got an intake.) the headers are gonna help to make the car a serious attention magnet. Whichever system you get, look for the biggest resonator you can get with it, keeps th sound down significantly and hurts flow none.

So in the end, it`s down to whether the extra noise is worth the possibly 1-5 hp difference (up top, identical below) for you.

 

Dc sport header has a 3" outlet, then get a random tecnology 3" in and 3" out catylitc, then get a 2.5" exhaust.......

 

2.5 inch if you are staying na... 3 inch if you are going turbo... 3 inch on a na motor will drop low and midrange power and torque... but yes you will have some small gain in top end... but the gain is not worth the loss of power in the lower end... just as a 2.5 inch exhaust on a turbo car would get you some small gain in lower rpm range of torque and hp but the loss of top end power is not wrth the lower rpm gains...

 

3 inch won`t lose anything significant to a 2.5
iWish iCould remember the different dynos out there that have proven it. the greatest drawback to the 3" exhaust KA is that it becomes audible for miles.

 

This is true, so use a silencer and it will help some.

 

It doesnt help much sometimes....And half the time it sounds horrible

 

i'd go with 3", but u run a higher chance of gettin pulled over.

 

Not to flame, but i think you're an idiot. There will be noticible torque loss in the low rpm ranges, and little gain as far as ponies go. I gould give a damn less about what dynos say, none register exactly the same any time. I go by the seat dyno... the further you get thrown back the better. My freind has a 95 240, and he had his stock exhaust on and when he switched to a 3", i could definately tell the difference. Plus, like you said, it will be audible for miles. But not only that, but it will sound like a farty civic. RESIST THE RICE go 3" for NA vehicles. Bigger is not always better, only ricers think that way. Look at their wings and bodykits, I rest my case.

 

if you are staying na 2.25 to 2.5

if FI then 3 to 3.25

it's the best for daily driving. hands down.

 

FI? You mean any fuel injected car? I hope not, or you deserve a nice slap. The 240 has breathing problems as it is... giving a non turbo 240 anything bigger than 2.5" exhaust is like blowing smoke in some kid with asthma's face! IMO...really... if you want to turbo the car eventually, go 3" otherwise youre gonna sound like a riced out civic and lose that precious valuable torque...

Just my 2 cents

 

Why spend more money on like 2 or 3 horses? Three inch could cost the same money initially. However, it will cost in the long run! Damn cops...

 

HAHA sucks for you guys. Cops in louisiana wouldnt care if you had NO exhaust on your car...

 

FI= Forced Induction.

3" doesn't sound ricey... it depends what exhaust you get. Mine doesn't get a very high bumble bee sound, and it's just 3" straight through... get a nice muffler and a resonator.

You guys and your huge anti-ricer ways... it's funny sometimes.

 

Oh, well with a resonator it does quiet it down a lot. Thats what i look for when i go to look for catback exhausts. Not only that, but instead of replacing my cat with straight pipe, i replaced it with a resonator. It sounds pretty good with stock exhaust and a bigger muffler, But i still want a catback, just lookin for the right one