2.5" dp all the way, any thoughts?

[sids]

Was reading some of the posts and everyone has a 2.5" DP then 3" catback, granted bigger will be better if you upgrade turb to a big ass one, but how about this?

2.5" downpipe, s.5" flex pipe, eliminate the cat and 2.5" mandrel bent all the way.

am still running the t25 and the biggest I'll go is probably 16g.

reason for this is that I already a 2.5" catback and it seems a waste to get rid of it since its hard to sell of.

in effect i'll just me shelling out a bit more cash for the 2.5" DP up to cat

thanks guys

 

[90GSTman]

I would say stay with the 2.5" catback. With the 16g I would guess the the 3" would make less than 5 hp over the 2.5". I'm still running a 2.5" (actually 2.36") and don't have any plans to go bigger till this one rusts out (aluminised steel).

 

[2BAD99GSX]

go ahead and get 3". you're going to want bigger eventually, TRUST ME. you get bored with your t25, so you get a 16g, then you're going to get bored with that too. i thought id be just fine with my t28, then u realize for just a little more you can go so much faster. rock the 3" dp with the 2.5 cat back for now, and then if/when u decide to go bigger all u have to get is the cat-back opposed to getting the cat-back AND the dp.

 

[90GSTman]

$570 EVO III 16G = 80 hp to 100 hp gain

or

$570 for 3" stainless cat back = 5 hp gain

If it was a choice to buy either a 2.5" or a 3" I would say go with the 3". But you already have the 2.5" so why spend so much money for so little of an increase. Spend the money on the turbo.

 

[2BAD99GSX]

confused.

if you already have the 2.5" downpipe, keep it and go for the turbo, i agree. but if you have the stock downpipe, which was what i was understanding, i would get the 3 incher.

 

[90GSTman]

2bad99gsx
Sorry, I read your post wrong. I thought you were saying to go with a 3" cat back system and ditching the 2.5".

 

[DSMeclipse4G63]

a 3in downpipe into a 2.5in cat back would create a bottle neck and cause back pressure....I would say go all 2.5 if your certain you will strop at a b16g....other wise do all 3in or 2.5 downpipe and 3in cat back(with ported o2 housing). Getting a 3in downpipe for a 2.5 system would be a complete waste...
Andrew

 

[sids]

sorry guys for the confusion, let me clear somethings up.

What i have now;
stock downpipe, stock flex pipe, cat converter, 2.5" catback

what i plan to do, 2.5" downpipe, 2.5" flex pipe, 2.5" cat eliminator, keep catback

from your replys it seems that siwtching to a 3" is awaste unless I go for a t3/t4 turbo or something honking big. trust me guys, 16g is my mostest mod, not much of a power junkie as my friend who just got a GT50 50 trim.

I know that EVO 3s come with 2.5" piping stock but the bends aren't that smooth and the down pipe I think is a bit smaller at 2"

so with 2.5" all the way, I would theoretically have better exhaust flow than a stock EVO3 which can be maxed to around 260whp.

hey that's plenty good for me =)

 

[DSMeclipse4G63]

I know what your setup and what your asking...Im just saying getting a 3in downpipe with 2.5 exhaust would be bad. 2.5 is good enough for any 16g or t28 turbo...3in would only yeild a littl more hp but not enough to buy it over getting a turbo.
Andrew

 

[snox135]

a 3in downpipe into a 2.5in cat back would create a bottle neck and cause back pressure....I would say go all 2.5 if your certain you will strop at a b16g....other wise do all 3in or 2.5 downpipe and 3in cat back(with ported o2 housing). Getting a 3in downpipe for a 2.5 system would be a complete waste...
Andrew

Yes it might create back pressure but it would less back pressure than a complete 2.5" exhaust. As the exhaust goes thru the pipe it cools and becomes denser there for taking up less room. A 3" down pipe with a 2.5 cat-back makes alot more sence than a 2.5" down pipe with a 3" cat-back.

 

[sids]

actually, te original plan is to redo the entire thing, not 23" downpipe into 2.5" exhaust but rather, 2.5" dowpipe into a 3 inch flex pipe. oing from big to small is not very smart.

anyway, I'm going to keep my 2.5" catback and make the downpipe 2.5" too so that it will be nice and consistent all the way

 

[Ry's_95tsi]

reason for this is that I already a 2.5" catback and it seems a waste to get rid of it since its hard to sell of.

I am actually looking for a 2.5 catback if you wanna sell it. Let me know what it is and how much you would want.

[email protected] or aim RBisson425