i want to know:

1. what piping diameter the greddy evo is and the apexi n1 is.

2. which would would yield better gains on a turbo'ed GSR?

please dont tell me to go 3inch because i think it would be too loud.

3. i know the n1 is straight through design, but is the greddy evo straight through too?

i am not going 3inch because i will be n/a for a while before i go turbo so 3inch will be too loud, too much. so 3inch is just out of the question, because this will be a daily driver anyways.

 

2.5 and 3" piping aren't going to has much difference between how loud one another is, what determines the decible level is more a function of your use or lack of muffler, resonator(s), and cat, and of course the engine set-up.

I'd go with 3" mandrel bent piping, and an Apex N1.

 

bump

 

come on man, no ones trying to help me out here?

 

All three of those questions could easily be answered by the manufacturers...its as easy as calling and asking them.

 

First off, to what I know, both APEX'i and Greddy use mandrel bends in all there exhaust bolt-on systems. So either will have smooth bends.

As for piping size on the exhaust, here are a few guidelines you can use:

1500cc~1600cc SOHC (NA) ----> 2" to 2.25"
1500cc~1600cc SOHC (NA w/NO2) ----> 2.5" to 3"
1600cc~1800cc DOHC (NA) ----> 2.25"
1600cc~1800cc DOHC (NA w/NO2) ----> 2.5" to 3"

1500cc~1600cc SOHC (Turbo) ----> 2.5"
1600cc~1800cc DOHC (Turbo) ----> 2.5" to 3"

With turbocharged engines, try to get mandrel bends on the exhaust piping, it will prevent backpressure onto the exhaust side turbine. The downpipe should also be the same diameter as the rest of the exhaust piping to maintain a consistent flow rate of exhaust.

If you can, try to pick up some of GReddy's or APEX'i pre-made "intended for a turbo setup" exhaust systems. For example, I think Greddy has something like the "PE - Power Extreme" for cars with turbos. Picking up an exhaust like this will ensure that you have smooth bends in piping after the cat, possibly best flow characteristics (optimized) for that motor size, and will gain more benefits when compared to crush bent or custom piping.

 

thanks for the answers

 

you live in MD...im almost sure they dont have emmissions...straight 2.5" from the turbo is my suggestion...if you do have emmissions...any 2.5" exhaust will do if you keep your boost under lets say 12 psi...

 

I know the Evo is a 2 1/4 which is flared to a 2 1/2 straight thru muffler

I know because I was thinking about doing that for my setup and called them.

 

i still don't understand why so many people stick with 2.5 whe boosting. 3" has been proven to net more power. the more boost, the more power you'll make over 2.5, with 3".

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by untensadude &raquo;</TD></TR><TR><TD CLASS="quote">i still don't understand why so many people stick with 2.5 whe boosting. 3" has been proven to net more power. the more boost, the more power you'll make over 2.5, with 3".</TD></TR></TABLE>

what I would like to know is how much tq will be lost going with a 3" exhaust and low boost. I hear so many people say, "don't go with 3" because u will loose low end tq and hp while out of boost", but would like to know about how much 5, 10, 30, etc....

I was thinking about trying to get the best of both worlds but still undecided
2 1/2 dp + high flow cat + 2 1/2 or 3" catback


anyone!!!

 

nobody?

 

It can also depend if the wastegate will be dumped into the exhaust. I'm having a time deciding on an exhaust setup. Don't know whether to go 2.5" or 3" The dp is 3 and the wastegate will be routed back into the exhaust so I might just go 3".

 

if you take a 5th gen prelude w/ a turbo kit (t3/t4) and you dyno it w/ a stock exhaust...and then you put a 3in exhaust on from the stock cat all the way back...wouldn't you gain tq??

 

why stick w/ a 2.5" over 3"...thats simple...its harder to run a 3" exhaust over a 2.5" exhaust...why put yourself through hell when you only want 250whp?

im sure there is a better more scientific answer...but i dont know it...all i know is 3" w/ 11psi will add about 5whp over a 2.5"...

 

yeah that is true. i will be running about 7-9 lbs of boost on stock internals. i will not start upgrading until later that is why i am not too interested in the 3inch. also this will be my daily driver and i will drive it alot so going 3inch without any aid of resonators is going to be pretty loud.

 

Maybe espanol can chime in, but i swear he a gained like 30+ whp from swapping out a greddy sp exhuast with a greddy power extreme II

 

greddy evo uses a 60mm pipe that is a little bigger than 2.25. N1 is the same-60mm. they are both designed for NA applications. they are both straight through the evo just has a little bigger diameter can (inside and out) out back. I doubt there would be more than a 5 hp diff between the 2 on a turbo GSR. 60mm is not ideal. check out accordinglydone.com make your own and feel the HPs yo

 

thanks for the replies. do you think i could call greddy up and ask them to make me a custom 3inch greddy evo unit? i know they have one for the wrx.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by thrty8street &raquo;</TD></TR><TR><TD CLASS="quote">thanks for the replies. do you think i could call greddy up and ask them to make me a custom 3inch greddy evo unit? i know they have one for the wrx.</TD></TR></TABLE>

I already tried for a 3" accord version but they said, mult times, that they don't do custom exhausts

It's cool though, it's cheaper to get a custom setup