2.5'' or 3'' Downpipe??

[ctnsupra1]

I'm getting a DP for Christmas but I'm having a hard time deciding what size. Should I go with a 2.5'' DP and test pipe or a long 3'' DP that replaces the cat? Right now I'm running a 14B and basic mods but planning on going bigger (20G, L1R) later on. Any thoughts or impressions on DP's? Thanks.

Conor
'95 GSX

 

[L2RTSiAWD]

this has to be one of the most asked questions along with 2.5 or 3inch exhaust.

Just get a 3inch or you will switch later.

 

[KooK]

I have a 3" downpipe on my 91 TSi and beyond 4500-5000 RPM I was getting HORRIBLE boost creep, as in I turned it down to 11psi and it was up at 18. I don't know if it'll also do that with a 2.5, I'm guessing it wont be as bad but just a heads up. I took my turbo out and ported the wastegate and O2 housing, I just finished putting it back in and I havn't started it up yet so We'll see how its doing tomorrow.

 

[DeezNutsForYou]

I want to run a full 3" turbo back, maybe with or without a cat. But does this mean that I will get horrible boost creep as well. And one more thing if you run without a cat do you really shout fire out of you pipe, because that would suck. Somebody on here has that problem every time he shifts and he says its from a lack of a cat.

thanks for any insight

 

[UltraImports]

Originally posted by DeezNutsForYou
I want to run a full 3" turbo back, maybe with or without a cat. But does this mean that I will get horrible boost creep as well. And one more thing if you run without a cat do you really shout fire out of you pipe, because that would suck. Somebody on here has that problem every time he shifts and he says its from a lack of a cat.

thanks for any insight

The only cars I have seen shoot fire out of their exhaust were two bad ass rx7's...1 1st gen, 1 3rd gen.....and of course tf&tf....but that was a joke. Since there isn't a cat, you will get some unused fuel go through, but I really doubt that it will ignite....at least I haven't seen that happen on any local high power dsm's.

 

[Nexius]

You have never seen a 2G backfire .... download this video

http://66.131.72.229:81/video/nexius.wmv

But I only made a backfire for the video. It never backfires on its own, I make it backfire.
The cat doesn't have much to do with the backfire. I run rich because I vent to the atm. and have a 255hp fuel pump, having a straight exhaust only helps

 

[DeezNutsForYou]

how can you controll that?

 

[KooK]

Hahaha, I cheat with my baja, I'm goina hook up a little flamethrower (just the sparkplug) because I run really rich alot of the time. I have to change the jets out of the carb

Heres me just messing around though

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[GBabyTSI]

my car shots out a flame from ex. but all i have is 3in dp and glasspackex stops at halfway under the car

 

[gvr4ever]

If you are going to have a larger turbocharger, i would definately go with the 3" downpipe/exhaust.

 

[AWDtsimang]

GO BIG OR GO HOME!

 

[InferiorWang]

i've heard of sticking a sparkplug in the exhaust before. and if you vent to the atmosphere it lets you run rich b/w shifts and scare the #### out of people in traffic. hehehe.

 

[ProStreetOnline]

Get the 3". If you think it's too big, put in a cat. On a turbo car, you can never have too much exhaust.

 

[Phoenix_RsX]

that is true. you can never have too much exhaust. but I'd honestly say it's dependent on what you wanna run. if you want high 12s-low 13's, go with a 2.5. if you want faster(like most of us) go with a 3" the times might be inaccurate....but just my .02

 

[herostar]

I was gunna post this exact same question... thanks for helping guys (glad I searched...)


Edit: Does anyone know where I can pick up a good inexpensive downpipe/cat eliminator?