2.5 cat back

[blackstang3o2]

My car currently has a extreme motorsports 2.5 cat back on it. How much power is there to be had by switching to a 3inch megan racing exhaust? I would like to keep the 2.5 since it is quiet but if im leaving 20hp on the table id rather have the extra power.

I should add its only a evo 16g turbo. Nothing major.

 

[KiNg MaRtY]

If you have a 2.5 downpipe with it I would think you may not see any results if just a bit by going to a 3". If you still have the stock downpipe and are thinking of just upgrading the catback, you should look into getting a bigger downpipe first.

 

[Dsmj89]

Keep the 2.5" exhaust system you currently have. If you switch over to a 3" system you will suffer the infamous and hated boost creep of the 16g.
Plus, 2.5" is good for up to 400hp. So just leave it alone unless you have plans for 400hp+.

 

[blackstang3o2]

thanks for the input. I get people that tell me 3inch is the only way to go. or man you have so much to gain with going with bigger. I just dont see it. I figured id ask here and get some input. I will just replace down pipe and cat then. Now I just got to find a down pipe that will work with my cat back. I was looking at punishment racing but theirs is 3 inch wont make much sense to have a 3 inch down pipe to run into a 2.5 cat back.

 

[Dsmj89]

Look on ebay, im sure they have 2.5" downpipes.

 

[KiNg MaRtY]

If you are getting a new downpipe because you are still using the stocker than just get the 3". That way if in the future you decide you want more power or end up with a bigger turbo you won't want to buy another downpipe. I think your chances of creep will be reduced since you plan on still running a cat and are staying with the 2.5. I have a 3" Megan downpipe with a 2.5 catback with no cat on my VR-4 and get no boost creep with my Big 16g. The downpipe made a nice noticeable difference copared to the catted stock Dp and 2.5 catback setup the car came with

 

[blackstang3o2]

Thanks again for the info. I did order a 3" Down pipe yesterday from DSM graveyard once that gets here Im gonna order a hi flow cat and hopefully I will be happy with the set up.