hi guys
i dont know which size downpipe should I buy, 2.5" or 3"
for the next couple of months im not planning to upgrade to a bigger turbo, and ill probably keep the stock exhaust too
let me know
pete

 

3 inches is perfect.

 

i found 2.5" on ultimate-racing.com
who sells 3" downpipes?
isnt 3" gonna cause problems with a stock turbo?
thanks
pete

 

my friend put 3 inch dwn pipe on his subi and it gave his car a huge increase. he also had all the piping and exaust 3 inches...sounds like a monster put together with a harley davidson. sounds nice.

 

RMR has a 3" downpipe for $299

 

never skimp in performance parts. If a "bigger/better" part is availible, get it. Since you will usually end up replacing the cheaper parts.

Exhaust is a big upgrade for boosted cars. the faster it can expel exhaust gasses, the more power it can make.

 

whats RMR?
No im asking because ive heard that big downpipe with stock turbo will casuse some ****
not sure though,

 

generally, 2.5" will give you good low gains that will be sacraficed with a 3" dp. however, high end the 3" rocks the 2.5"... i'm not an evo driver... my 1.8t loves the low end and kicks off around 4.5-5k... so 2.5" is perfect... you guys have the luxury of 100 more hp, and about a half litre. i dunno if your turbo's peak high or low.

 

I would go with 3" but don't stop there...also get a elbow.

 

i wish there was a website that would HONESTLY explain advantages/disadvantages of all things they sell,
pretty much every website that sells parts claims they are the ****, but then you buy them and find out that they didnt work as good as claimed.
i think im gonna wait few months and let other people try out everything, then follow the winner

 

That is incorrect, perfdrug. Unlike a NA motor, a Turbo will not lose low end power from a bigger DP (provided the Turbo doesn't over-spool). The Turbo will spool up faster and flow better. '3 is the way to go. Hell, I have a '3 on my 1.8T and it rocks.

 

Bigger is better with forced induction. You don't have to worry about losing low end with a bigger pipe, cuz it'll just help you spool up that much faster with the increased exhaust flow.

 

The evo is a new car for the US. And japanese reviewers are notoriously biased, even more so than US mags. All things come with time, but using common sense and knowing basics of mechanical engineering will never steer you wrong.

In this case, we want an exhaust/downpipe combo which yields the most power. The mechanics behind a turbo would dictate a larger hole/pipe to kick out the exhaust will allow the turbo to work more efficiently, thusly creating more power.

MANY of the exhausts you see on the market are purely rice mods. Full of bends and rediculous resonators for tips. Look at the big turbo cars and race cars. Its a big pipe, no fart can on the end.

 

If anyone has seen a picture of the Evo's engine, the turbo/wastegate dumps into an elbow before it gets to the downpipe. My question is, how much hp could be gained from replacing that? (assuming 3" turbo-back exhaust has allready been installed)

 

That would be hard to give a specific gain in numbers...not many people dyno before then right after with one-piece(small) mod. Most people do dyno testing after stage tuning. This group of mods then dyno next set of mods then dyno again. My best guessestimate would have to be anywhere from 10-15hp that being a generous estimate. PEACE