Here Kitty Kitty
Thread Starter
Burning Brakes
Joined: Dec 2004
Posts: 905
Likes: 0
From: Rhode Island
Here Kitty Kitty
What is the downside (if any) to removing the cats. I have long tube headers and I'm going to install a GHL or B&B cat back. Will there be any power gain if I just eliminate the cats and add an X pipe?
Racer
Joined: Jul 2004
Posts: 412
Likes: 0
From: Newport AR
Interesting point, what states have emission laws? All I know is CA and AZ. We don't have any vehicle inspection of any type in Arkansas, so you can run anything anywhere. When I lived in AZ an emission test always cost me several hundred to reinstall all of the required crap, retune the engine to pass, then take it all back off and retune it to run good, but that was better than driving a POS so that some tree hugger could get his rocks off.
Thread Starter
Burning Brakes
Joined: Dec 2004
Posts: 905
Likes: 0
From: Rhode Island
The reason I ask is because I have seen a lot of posts saying that the gains are negligible. However, I used to own a 454SS pickup and when I removed the catalytic converter the thing came alive. I thought maybe the old converter was just blocked, but, when I installed a brand new converter (stock) the thing bogged down again. It was really noticeable.
Drifting
Joined: Nov 2003
Posts: 1,894
Likes: 6
From: Sahuarita AZ
Originally Posted by drochau
I don't think you can remove/gut the cats in New Mexico and still pass emissions testing. At least not in my county.
I wasn't aware New Mexico had any emissions testing... what county are you in?
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Le Mans Master
Joined: Feb 2002
Posts: 5,407
Likes: 1
From: HONOLULU HAWAII
You will also have a gas odor in the cabin when you are stopped and idling. I have read many posts from people saying they regretted eliminating the cats.
Last edited by WWK888; Jan 14, 2005 at 07:41 PM.
Cherish your Hopes...
Joined: Feb 2002
Posts: 13,072
Likes: 236
From: West Palm Beach FL
Cruise-In VII Veteran
St. Jude Donor '05-'06-'07
Originally Posted by CAJUNY2KC5
Might be some slight legal ramifications if caught....... 
so I went HHi-flow cats...and no hair *****...
Louder and more agressive with X-pipe and B& B Bullets...
...or take them off...onluy gets louder...
I think there is more power and dyno supports that...
... Ill be listening for you decision...
Race Director
Joined: Oct 2002
Posts: 11,945
Likes: 12
From: Vancouver
2015 C5 of Year Finalist
St. Jude Donor '05-'06-'07-'08-'09-'10
Good thread. Interesting observations. I didn't think you would get any smell unless you were burning rich With a catylic converter. With no cats it should be like in the old days of smelling gas out the exhaust. Any ideas?
Burning Brakes
Joined: Nov 2004
Posts: 822
Likes: 0
From: Grafton Ohio
I'mrunning lt's and no cats. The thing is a little stinky at startup but once at running temp. it's fine. Only when my top is down, at a stoplight, in a light, wavering tailwind, can I smell a little exhaust. It's all in the tune imo.
Thread Starter
Burning Brakes
Joined: Dec 2004
Posts: 905
Likes: 0
From: Rhode Island
Originally Posted by stuart
so I went HHi-flow cats...and no hair *****...
Louder and more agressive with X-pipe and B& B Bullets...
...or take them off...onluy gets louder...
I think there is more power and dyno supports that...
... Ill be listening for you decision...
Louder and more agressive with X-pipe and B& B Bullets...
...or take them off...onluy gets louder...
I think there is more power and dyno supports that...
... Ill be listening for you decision...
Melting Slicks
Joined: May 2003
Posts: 3,494
Likes: 0
From: McKinney Tx
Cruise-In V Veteran
St. Jude's Donor '05
I'm running off roads pipes and I run a tad rich because of the cam. I picked up 5hp when we removed them. Yeah there was alittle power in crease on the dyno but nothing that I can feel on the street 
Instructor
Joined: Nov 2004
Posts: 101
Likes: 0
From: Tampuhhh Floriduh
In modern NA cars, from what I understand anyway, a good hi-flow cat with properly sized exhaust is damn near as power efficient as no cats at all. In the turbo world, it's a totally different ballgame, but that is what I've read/been told about NA applications.
Supporting Tuner
Joined: Sep 2004
Posts: 51,896
Likes: 39
From: ================== Houston, Texas www.englandgreen.com ================== Necessary Evil™ __________
CI 6-7-8-9-10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14
It is against Federal law to remove or replace your cats if your car is less than 10 years old. If they are replaced, they must be replaced by the manufacturer and must have been defective.
All that being said - as soon as I install my LGs, I'm going with Random Tech hi flow cats
I'll go quietly, officer
EG
All that being said - as soon as I install my LGs, I'm going with Random Tech hi flow cats
I'll go quietly, officer
EG
Le Mans Master
Joined: Jun 2004
Posts: 6,269
Likes: 50
From: Dallas Texas
St. Jude Donor '06-'07-'09-'10
Originally Posted by AFVETTE
And I don't want to drive behind a car with gutted cats.
Tom
Tom
I followed one, who shall remain nameless, in my Vert on a cruise last Fall and talk about smell. Peeyu! 
There ought to be a law. 
Racer
Joined: Mar 2004
Posts: 271
Likes: 0
From: Stockton CA
Originally Posted by EnglandGreen
It is against Federal law to remove or replace your cats if your car is less than 10 years old. If they are replaced, they must be replaced by the manufacturer and must have been defective.
All that being said - as soon as I install my LGs, I'm going with Random Tech hi flow cats
I'll go quietly, officer
EG
All that being said - as soon as I install my LGs, I'm going with Random Tech hi flow cats
I'll go quietly, officer
EG
The Federal Law states that you can not totally remove your cats legally at any time, but you cannot replace them unless defective sooner than 50,000 miles or five years. And I could not find anything in the verbage about having to be replaced by the manufacturer. Any muffler shop in CA can replace the cats, if they are proven to be defective.
Sempi
Supporting Tuner
Joined: Sep 2004
Posts: 51,896
Likes: 39
From: ================== Houston, Texas www.englandgreen.com ================== Necessary Evil™ __________
CI 6-7-8-9-10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14
Sorry, I meant the original manufacturer's cats. :o
Le Mans Master
Joined: Dec 2003
Posts: 7,457
Likes: 144
From: NC
Here in NC, if your car is 1967 or newer (no, that is not a typo) it better have every emmissions piece on it that it came with from the factory or it will not get the required money generating inspection sticker put on it that is required for it to be on the road. Get caught without it and it is a quick $250.