Suggestions on Exhuast size please.....

[dkorinko]

Hey guys, so I found a local shop that i trust to work on my car but i was wondering what exhaust combination I should go with, I was thinking of using 2.5" piping since my car is pretty much stock but i wanted everyones input. The only mods my car has is the top gun chip, theromstat, and a K&N filter on the turbo. I plan on adding a front mount intercooler, turbo, and injectors but thats not going to be anytime really soon so would 2.5" piping be the size I should use??? Also does anyone have a good recomendation on what cat I should use??? I appreciate the help guys.

[TGed]

3" or close to it would be what I'd do.  For forced induction you really want to go big as you can for an exhaust.  Now 4" MAY just be pointless for the OEM type of vehicle, but would open the window for future modifications.

2.5" would be ideal for N/A engines, you're not N/A you're F/I  :icon_wink: .


Make sure you do from turbo (down pipe) back if you really want to see the true gain.  What you could also do is have 3" from the turbo down to the catalytic converter and install a cutout right before the catalytic converter.  Then after the catalytic converter install 2.5" back to the mufflers. 
Make sure you use mandrel bent style exhaust or atleast pressbent.  Stay away from ripple bent exhaust since it disrupts flow and cause raspcrispies.


.02

[mfewtrail]

2.5'' is plenty. TurboSedan's old 5spd/turbo 3.1 Cutlass put down more power than most people make here with a stock catback minus the catalytic converter for what it's worth. ;)

EDIT: The only way I would go larger than 2.5'' is if I were using a non-stock turbocharger...

[dkorinko]

I was thinking 2.5" would be good... the car has the stock cat on it with 179k miles so im sure it will enjoy the extra breathing room.

[TGed]

The only mods my car has is the top gun chip, theromstat, and a K&N filter on the turbo. I plan on adding a front mount intercooler, turbo, and injectors but thats not going to be anytime really soon so would 2.5" piping be the size I should use???

The only way I would go larger than 2.5'' is if I were using a non-stock turbocharger...

Why spend double the $$$ when you could do it all now.  You will not hurt performance by going larger now, it may even improve your 60' and ET.