Hey guys/girls,

I'm in the process of building my spare H22A4 with a full Turbo setup (sleeved, o-ringed, JE pistons, Eagle rods, Crower turbo cams, Crower valve train, Hondata S300, AEM FPR, AEM High-Flow FR, RC 700cc injectors, Walboro fuel pump, T3/T4 TO4E .63AR/.57 Trim turbo, custom made header style turbo manifold, 33"x12"x3" FMIC, 3" IC piping) . I plan on running more than 15psi of boost, so with that said.... I currently have a Greddy EVO1 cat-back, will I need to replace it with a bigger diam. exhaust pipe after the turbo is installed? If so, is it possible to only upgrade the exhaust piping and not the axle back? I really love the look/sound of the Muffler itself, and I'd hate to get rid of it.

Please let me know.


Thanks!


Modified by ImPuLsIvE at 12:50 AM 2/13/2006

 

you CAN keep it if you want, but you will have to deal with back pressure. even if you change the exhaust pipe and keep the axle back, you will still have back pressure at the axle back. i had a greddy PE, which technically flows a little better than the evo, and i had backpressure on my NA motor. the only way to get rid of the backpressure is to get something that flows better and is meant for turbo use. but like i said, you CAN keep the evo, you will just have to deal with a little pressure. i miss my PE, it sounded so good ask in the turbo forum what muffler they would recommend.

edit: i see lots of people have viewed this thread...no input guys?

 

You don't absolutely have to.

But you'll definitely benefit from a bigger pipe. If you love the evo I think there is an Evo TT for turbo cars, don't know how big a pipe it is though.

 

The EVO-TT has a 70mm diam. pipe, compared to the regular EVO which has 60-70mm pipe (I'm not sure which actual diameter it is, as that's the information I could find, including the Greddy website).

So, the EVO-TT is 2.75", and I'm guessing the regular EVO is 2.25". Also, the EVO-TT isn't available for the 4th gen Prelude, only the 5th gen. Maybe getting the EVO-TT Axle back from the 5th gen would fit custom piping on a 4th gen? Hmm..

And I've tried posting in the Turbo Prelude thread, but it's so disorganzied that either no one answers my question, or I simply can't find the answer.

 

4th gen and 5th gen exhausts arn't wildly off, it should just be a length difference in the b-pipe.

You really could go bigger than 70mm with your build though.

 

I'm keepin my Evo on my car with my setup. Yeah, i'll have backpressure - but it won't be too bad. i'll only be boosting ~10psi or so though. I'll probably change the exhaust to 3" or so once i'm done with my n/a civic.

 

Id up the sizing of the exhaust. Ive got a 3" pipe all the way back on my SE-R and it made a pretty big difference in the power compared to the 2.5 it had before.

 

Or you can get an exhaust cutout like I'm looking into for my build. Run your Evo that you like most of the time, and with the flip of a switch run open downpipe and make more power and less lag then a 3 inch exhaust could make.

 

You COULD keep it on there, but it's not the greatest thing.

I won't talk out of my ***, but I know that with the tighter pipes and the good increase in power you'll be pulling from 15 pounds on the turbo, you will be flowing a lot of air through the motor, and exhaust-reversion due to compressor-side backpressure is NOT something you would like to encounter!

 

I guess I have accept the fact that I'll need to replace my Greddy EVO... It disappoints me quite a bit, as I love my EVO, but considering the amount of power I'll be creating, and with exhaust back-pressure in mind.. This needs to be done. ;(

With that said, I'm going to be adding a 3" flex-pipe, highflow 3" in/out catalytic converter, 3" mandrel bent piping and the muffler pictured below, following my 3" downpipe. What do you guys think of this muffler? The specs of it are written below.



Magnaflow 5" x 8" Oval Race Series Polished Stainless Steel Muffler - Part# 14835

DESCRIPTION:

Double Wall, Angle Cut
3" Inlet, 4" Diam. Tip
3" Internal Race Core
7" Tip Length
5" x 8" Oval Body
14" Muffler Body Length

---------

It doesn't compare to the look and possibly the sound of my EVO, but I guess it'll have to do.

 

id be more worried bout the 550cc injectors rather the exhaust

 

Yeah, I'm going with 700cc.. I have no idea where that 550cc came from.. LOL

 

my other option would be to get an Apex-i N1 muffler... 3" inlet, 4.5" tip.



The only problem with that muffler is that i've heard it on a lot of cars, and it makes them sound like a pissed off bumble-bee

 

Just like everyone said, you do not have to change your exhaust. And please leave the term "backpressure" out of your reasoning. It is called pressure gradient or pressure drop and that is not what is going to kill power. It is like trying to blow through a coffee straw vs a mcdonalds straw... more airflow=more power for a setup pushing 15lbs of boost. Your looking at 400whp with this setup and a 3" exhaust could give you as much as 20whp