I have a '94 Integra GSR, turbo'd. Currently has 2.5" downpipe w/ 2.5" exhaust piping all the way back (no cat). I would like to do a custom bent 3" exhaust by a local shop, but not sure if this is a good idea w/ the 2.5" downpipe. I definitely want to keep my air conditioning fully functional. I tinkered w/ the idea of a Lovefab manifold, so I could do a 3" downpipe, but not sure exactly what model to get, and don't have tons of extra $ right now. Any help is appreciated. Thanks

 

its perfectly fine to go from 2.5 to 3", alot of people on her are doing that. You wont get AS GOOD of gains obviously, but it wont really hinder you too much. Just get the end of the downpipe flared to 3" and you will be fine. You also may wanna look at the onefab manifold. Its about 700 bones but its AC compatible and is ******* hot.

 

What is your compression ratio?

 

i have a 2.5in DP to a 1.75in stock cat to a 3in exhaust

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by graphic &raquo;</TD></TR><TR><TD CLASS="quote">i have a 2.5in DP to a 1.75in stock cat to a 3in exhaust </TD></TR></TABLE>

can you say " im sufficating"

 

wtf made you go with a 3" exhaust and keep the 1.75" cat? That 3" exhaust didnt do **** for you with that cat on there. Your getting so much back pressure it would be rediculous.

 

i heard the aftermarket 3in cats...suck

and the brick goes in like no time...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CrazyModGSR &raquo;</TD></TR><TR><TD CLASS="quote">I tinkered w/ the idea of a Lovefab manifold, </TD></TR></TABLE>

haha^

ya 2.5 to 3" is good if you are making **** tons of power. 2.5" supports quite a bit though so if you aren't up there yet spend your money on tuning and brakes and good tires and suspension...

 

wow you need to open that thing up and feel the power, thats killing you really bad, the hot exhaust gases expand in your down pipe and then have to fit throught 1.78 inch pipe then back to 3 inch that cat has to go do that and you will have a diffrent car on your hands

 

you will have no problems going form 2.5" to 3". Most people have it done that way because they don't have room for a 3" downpipe.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TurboChrgd_Civic &raquo;</TD></TR><TR><TD CLASS="quote">you will have no problems going form 2.5" to 3". Most people have it done that way because they don't have room for a 3" downpipe.</TD></TR></TABLE>

 

What if you have a 3"DP with a 3" Cat and a 3" flared to 2.5" Exhaust? Any problems with that?

 

With exhausts its always ok to go larger downstream. Tho its never ok to go smaller. It really screws with the gas flow and the back pressure. If youre gunna keep that cat then u would be better off with a 1.75 downpipe, seriously.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by UK CIVIC B16A2 &raquo;</TD></TR><TR><TD CLASS="quote">With exhausts its always ok to go larger downstream. Tho its never ok to go smaller. It really screws with the gas flow and the back pressure. If youre gunna keep that cat then u would be better off with a 1.75 downpipe, seriously.</TD></TR></TABLE> this is right because the min exhaust comes out of the turbo its hot and wants to expand so the more room you give it the easyer it can flow, but when you try it make it go into a smaller pipe after it has started expanding in a bigger pipe it has to squeez its way in and is much harder to flow.

 

is the idea not to pinch flow? so any pinches would be bad for flow. more flow (easier flow) the better off u r. hope im not mistaken. so a 2.5" after a sequence of 3" would be a bottleneck.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by graphic &raquo;</TD></TR><TR><TD CLASS="quote">i heard the aftermarket 3in cats...suck

and the brick goes in like no time...</TD></TR></TABLE>

Well a 3" cat would be better than your 1.75" stock one

Heres a suggestion why not elimate the cat completely, and just have a pipe added to your Downpipe? Unless your state emmisions is out of control like California.

Iggy who didnt know People still ran Cats

 

When I first put my turbo on I had it setup as 2.5" to stock cat to 2.5" tanabe exhaust. Then I upgraded to a 3" carsound cat to a 3" thermal. That was a total difference in spool up time and power. When I finally got rid of the cat it made a bigger difference. Get rid of the cat and you'll be happy. It won't be to loud

 

How much louder exactly are we talking with no cat. I've been contemplating chopping off my 2.5" cat and just getting a straight pipe.

Right now I have a 2.5" downpipe, 2.5" carsound cat, 2.67" kakimoto exhaust. I just kept the same cat/exhaust from my all motor setup so it worked out good. Now im just thinking about eliminating the cat. I don't really want to part with the exhaust unless a local wants it and then I can hit up kteller8 for a 3" exhaust. But for now it'll stay the same (just wondering how much power gains ill see from a straight pipe instead of my cat.

 

i live in NJ and will need a cat...so i guess i will try the 3in carsound...and if the brick falls apart...fawk it