3" with 2.5" exit OR 2.5"
 

I was thinking about purchasing a header and downpipe combo. More than likely I'll go with ZZP's combo.

With a 3" downpipe and 2.5" exit, what will the benefits be with a 2.5" exhaust?
What would the benefits be of having a full 2.5" exhaust?

What setup are you running?

yea im also interested.. i wanna get the zzp downpipe witht the high-flow cat on it.. would this bolt right up with the megan cat-back and to the stock headers???

It probably would be best to go with the combo. You get more for your money, you know?

3" with 2.5!! trust me. i did that with the zzp so it would bolt up to my corsa. and guess what? i started making more power and i was like, hey, i want a bigger exhaust for more flow. so i bought the 3" hahn and i could use the 3" dp. all you have to do is go the the muffler shop and for 50 bucks they will cut off the 2.5 and put the full 3" in its place. plan ahead buddy

yes, if you get the long dp. only get the short dp if your running midlengths or long tubes

Your exhaust will only flow as well as the most restrictive part. IE: the 2.5" catback will limit the flow of the 3" downpipe to it's level.

The Megan catback is very nice. It's what I use, along with a Clear Image Header and downpipe.

Oh yes, and the style header you get will effect what it helps.

Shorty = High RPM gains, with some low end loss
Long tubes = Low RPM gains
Mid Length = Low & Middle RPM gains (mostly middle)
Tri-Y & other staggered designs = Full range gains (not as high as the other three styles, but across the board. $$$ compared to others due to fab difficulty)

So if you want to get more low end, you get a long tube. Want help at the top of your rpm band, get a shorty. Want something decent all around, a mid length. Want better then a Mid length and got the money to pay for it? Tri-Y or another of the staggered designs. I would suggest getting at least your head and downpipe ceramic coated as well.

Okay, now that that's answered, is a shorty header better or midlength. What are your preferences over high flow cats or no cats. Please tell me your reasoning. Also, what model would you suggest? 1.5" or 1 3/4?

What does this mean also? :lol: I'm kind of new to modding cars.

1 3/4 more flow. you will want it once you start getting more power. but you have a 2.4 so im not sure

I'm afraid I'll be running too lean?

2.5" on a basically stock 2.4? A little bit of an overkill don't you think?

What the hell are you talking about?

hes talking dp im sure. but your not making enough power to be running even a 3"!!! your losing power once you start going big like that. especially on a car that doesnt even touch 190

go with the 2.5 full back. the rule of thumb is 1" for every 100hp will be the most efficient.

right now i just ran a mustang dyno and put down 237/211 with a 2.5 zzp header/dp with corsa touring 2.5.

my brother with the same mods but with a smaller pulley (im stg2 hes 2.9) and running the vibrant 3" dp to a 2.5 corsa put down 237/214. So he has a smaller puller and a bigger dp, yet i put down the same power. also both cars have identical mods with the same stg 2 tune

^proves what i just said

yep lol. exhaust size is a bitch because you have to change it constanly if your planning on more power

yea im a noob on the exhaust mods.. but can someone help me out... the megan has the 2.5 inch piping correct?? so what options do i need for everything to work out right?? http://www.zzperformance.com/cobalt_...=540&catid=155

So you're wating to put the same DP and exhaust piping that most LSJs with stage 2 and other bolts ons use in your maybe 140 WHP car?:lol: By all means, go for it.

megan is 3" if im not mistaken

lol i agree, bigger is not better. your hanging out with honda guys to much lol

to the thread maker = if you want to make the most power pick an exhaust size in your hp range or your hp range that you plan on being in in the near future.

for example, i was hoping to be in at 300hp, but that fell on its face and im only making about 240 on a mustang dyno. i was losing power running a 3" header/dp, so i dropped to a 2.5. I might be keeping to header/dp therefore if i do get that high, i can upgrade and utilize the new power to its full extient

now if you plan on making anywhere from 220-250 go with a 2.5, other wise a 2.25 maybe a good choice for you if you plan on being fairly stock

ah so is the megan a 2.5 or 3 inch?

2.5 .

2.5"

Has it, I have. :D