2.5'' downpipe that let's you keep the cat ?

[GST_RIC_99]

Ok so I'm looking for a downpipe that let's you keep the cat. I want to go with a 2.5'' so I wont get boost creep good advice from a friend told me about this.I search online but no luck yet. I know the srs and the Megan downpipe fits perfect but it deletes the cat and I also look at RRE downpipes and it says it only fits Espelier, RSR or Apex N-1, RS, WS or Dunk exhaust systems only

I was wondering is their any other downpipes out there that is a 2.5'' and lets you keep the cat that will bolt up to a srs if that's even possible.I really want to try and make decent hp and still keep the noise level ok and for emission when it's time to smog i decided to go this route so i wont have too much trouble in the long run

 

[Pipnorcali]

With a evo3 your gonna want 3" I run a cheap catco 3" cat and just had it welded in for cheap I keep my stock stuff for smog time...

Search around about boost creep but 2.5 is gonna cost you a few hp

http://www.dsmtuners.com/forums/art...boost-creep-modified-wga-peepers-mod-how.html

If you gotta stay 2.5 the bushar used to have one or the rre and have the local shop weld up the exhaust to fit

 

[Jeff99GS]

Just get a clamp on High Flow Cat. They still pass emissions but have a better flow rate and will clamp right up to a 2.5" or 3" exhaust/downpipe

 

[GST_RIC_99]

With a evo3 your gonna want 3" I run a cheap catco 3" cat and just had it welded in for cheap I keep my stock stuff for smog time...

Search around about boost creep but 2.5 is gonna cost you a few hp

http://www.dsmtuners.com/forums/art...boost-creep-modified-wga-peepers-mod-how.html

If you gotta stay 2.5 the bushar used to have one or the rre and have the local shop weld up the exhaust to fit

I read that one awhile back & other links on getting rid of boost creep. I know the different ways to do that but I just want to avoid porting to be honest due to not having experience in porting and messing with the waste gate. 3'' would be nice but I heard the 2''5 is another easy way so im looking into doing this

Just get a clamp on High Flow Cat. They still pass emissions but have a better flow rate and will clamp right up to a 2.5" or 3" exhaust/downpipe

not sure if i'm understanding what you mean ? are you saying get a hi flow cat and a clamp ? this will bolt up to a 2.5'' or 3'' what clamp will i be looking for and hi flow cat companies i heard won't ship to California.

 

[iceman510]

Pretty much aftermarket cats are not legal in California.

 

[Roberti 2G]

Check out the stuff on Ebay. I ran one on my first GST and it used the stock cat. They arent the best brand names but they get the job done for exhuast products.

 

[T is for TURBO]

Check out the stuff on Ebay. I ran one on my first GST and it used the stock cat. They arent the best brand names but they get the job done for exhuast products.

He's from California. They have very strict regulations on aftermarket catalytic converters, you can't just throw a run-of-the-mill ebay at on and pass emissions.

 

[Pipnorcali]

I live out in the country so it's still the old smog test

 

[GST_RIC_99]

I was thinking of still using the stock cat and use a shor downpipe if I can find one or if anyone know where to get one

 

[Pipnorcali]

Why even bother with a downpipe to a stock cat ? I was running 106mph on a stockdownpipe n cat , It would have to be custom made if you want it done though .

 

[GST_RIC_99]

I know two people that live in Texas my ant & friend from high school so I can order a hi flow cat.I just need a dp that will still be able to use a hi flow or stock cat if not I guess I have to call around to see if a shop can customize one for me

 

[Gus@RRE]

None exist that i know of. With your factory cat, upgrading your downpipe won't really make any difference anyway. If you are trying to keep your factory cat, just keep your factory downpipe and be done. If not we do have 2g 3" short downpipes and 3" high flow cats.

Gus

 

[GST_RIC_99]

None exist that i know of. With your factory cat, upgrading your downpipe won't really make any difference anyway. If you are trying to keep your factory cat, just keep your factory downpipe and be done. If not we do have 2g 3" short downpipes and 3" high flow cats.

Gus

how much are they both the hi flow cat and short downpipe + shipping can i get a quote ? I live in California so shouldn't be far from you guys maybe I can just get both and have a shop fix the flanges to fit with my srs cat back.

 

[99GS_Turbo]

how much are they both the hi flow cat and short downpipe + shipping can i get a quote ?

Eclipse Exhaust System Upgrades

 

[Jeff99GS]

not sure if i'm understanding what you mean ? are you saying get a hi flow cat and a clamp ? this will bolt up to a 2.5'' or 3'' what clamp will i be looking for and hi flow cat companies i heard won't ship to California.

Sounds like you got this figured out, but what I meant was a Slip on Type High flow Cat that you can band clamp in place. The parts Gus has should work perfect for you. The Downpipe and cat have slip joints, the pipes slide together. They can then be welded or clamped together. There is NO flanges that neck down and cause a restriction to the flow of exhaust gasses. Most cheapo (ebay) 3" exhausts neck down to a 2.5" flange and then back up to a 3" pipe. Basically those 2.5" flanges cause the restriction in the flow of gasses. To have a true 3" exhaust it's better to have welded joints with a slip on cat and 2 band clamps holding the cat in place.
The Down pipe will slip into the inlet of the cat and the Outlet of the cat will slip into the Cat back system. Then use band clamps or strap type exhaust clamps to hold the cat in place. That will give you the ability to remove the cat to install a 3" test pipe if you ever take the car to the track and want to run catless.

Since your catback section has a 2.5" two bolt flange, you would have to cut off the flange and use a 3"to 2.5" adapter to go from the 3" outlet of the cat to the 2.5" Catback pipe that you just cut the flange off of.

 

[GST_RIC_99]

Is it necessary to have a 3" dp ? How much of a difference of a 3" vs a 2.5" could I get away with having a 2.5".I was thinking since you guys mention a test pipe that would be a good idea switching if I need to it might turn out to be a good turboback exhaust thinking about a EVO 02 housing too since it looks stock