Well guys I ordered a 2.5 inch cat back exhaust yesterday to finish up from the down pipe back all in 2.5 inch. My question is should I run a catalytic coverter or a test pipe? I am on 9psi right now and as for emissions laws our state is supposed to be dropping them come January. If you could let me know your input because I am still having mixed feelings even after reading the other posts. Thanks in advance!


~Boost. Its what's for dinner!~

Just run the cat... no matter what any one says the amount you will gain by removing the cat is small relitivly speaking (as i dont think your racing in pro stock or any thing like that) plus your safe then with your laws...

I have ran 2 different exhaust systems on my car... one was a full 3" turbo back no cat second was a 2.5" with cat... i felt like i had lost power... but it was all in my mind because it sounded different.. i could still walk all over my buddys the same with the 2.5" and cat as i did with the 3" and cat....

in the end i went with the 2.5" one because it was also quieter... (20" resonator, high flow cat and 2.25" inlet on my magnaflow muffler) not only is it VERY!!!! quiet.. its more stealthy now..



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I always say for a turbo car go without. My turbo car had a highflow one, and it cause issues with blowing wastegate gaskets, and turbo to manifold gaskets. Also my turbo car with 3inch exhaust is much quieter than my 01 all motor car with 2.5 inch exhaust. Turbo cars usually are. Test pipe is cheaper as well.



FU Tuning

A test pipe always favors more power in a turbo car unless something isn't matched up well!


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either will work well. I have tried both, with a turbocharger it doesn't sound stupid not to have one.


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John Higgins wrote:I always say for a turbo car go without. My turbo car had a highflow one, and it cause issues with blowing wastegate gaskets, and turbo to manifold gaskets. Also my turbo car with 3inch exhaust is much quieter than my 01 all motor car with 2.5 inch exhaust. Turbo cars usually are. Test pipe is cheaper as well.

LE61T PTE6262 Powered

forget the cat

it'll clog, it will choke the turbo, and keep heat where it isn't supposed to be...

the best exhaust system for a turbo is no exhaust at all

Tim what part of CO are you in. Not all of CO is losing the emission law

Okay, I just had reinstall my cat(hi-flow,brand new 2.5") for my emissions here MO. I can tell you from having a straight open test pipe to going to a cat I lost power. Gauranteed! My car pulled way harder without it, and the loudness is minimal without the cat vs. with. Just keep the cat pipe flanged and reinstall for inspections. It's a PITA to crawl under the car and swap it in and out, but its worth it!








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LE61T PTE6262 Powered

Okay. I live in Falcon area about 15 miles east of the Springs. I guess I will try a high flow cat and get it setup and then maybe around christmas order a test pipe to slide in there.


~Boost. Its what's for dinner!~

move to florida , no emissions

KY also no emissions!!!

I lived in both states I say come to fla, no winterizing your car..

only cars that benefit in hp by keeping the cat are NA, if its turbo, no backpressure needed....test pipe it is



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why not just get a cat and then gutt it like i did, im charged but same deal, its there for looks only.

BOOSTED wrote:why not just get a cat and then gutt it like i did, im charged but same deal, its there for looks only.

if you are going to gut the cat get a piece of tubing welded though the center...the turbulance a gutted cat causes is sometimes worse than having the cat itself



2007 GM Tuner Bash...HELL YEA
PA,MD,NJ,DE,NY and all states north caravan

John Higgins wrote:I always say for a turbo car go without. My turbo car had a highflow one, and it cause issues with blowing wastegate gaskets, and turbo to manifold gaskets. Also my turbo car with 3inch exhaust is much quieter than my 01 all motor car with 2.5 inch exhaust. Turbo cars usually are. Test pipe is cheaper as well.

listen to this guy, he knows what he is talking about

I found a catco one but it says "these are not recommended for OBD2 vehicles". http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=8072385295&rd=1&sspagename=STRK%3AMESE%3AIT but I thought I remember a bunch of people on the org. here running them. Any input would be great. Thanks in advance!



~Boost. Its what's for dinner!~

Would running just 2.5inch pipe with a O2 sensor installed throw a code or should I still get a cat? Doing this all this weekend so trying to get everything figured out. Thanks in advance!


~Boost. Its what's for dinner!~

Get an 02 sim, because yes without a cat your sensor will throw a code.

dont put any cat on the car! I had few boost problem before i remove mine!! boost is comming faster and I feel my car going better without the cat






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You do not want any restriction on your exhaust with a turbo car. I had a mag high flow cat on for a while and it clogged. The best exhaust for a turbo car is an exhaust that is a minimum of 2.5" with no restrictions such as cats, muffler baffles and silencers.

Quote:

forget the cat

it'll clog, it will choke the turbo, and keep heat where it isn't supposed to be...

the best exhaust system for a turbo is no exhaust at all

Dragracemyz24 is no more . Chupacabra devowered.