what they said
clogged pre-cat?
Thread Starter
Racer
Joined: Mar 2004
Posts: 305
Likes: 0
From: Houston Texas
clogged pre-cat?
Please excuse my ignorance, but what is a clogged pre-cat?
I was reading some of the past threads, and came across this.
The thread was about a C4 running rough, and one of our members suggested that a clogged pre-cat might be the problem.
I was reading some of the past threads, and came across this.
The thread was about a C4 running rough, and one of our members suggested that a clogged pre-cat might be the problem.
Race Director
Joined: Feb 2003
Posts: 16,475
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From: Kingman AZ
Cruise-In VII Veteran
Cruise-In VIII
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16
Her's a pic from an 86. They are the fat metal objects on the front Y pipes.
Here is a pic of a catless front Y pipe before I installed it on my 87.
Here is a pic of a catless front Y pipe before I installed it on my 87.
Advanced
Joined: Jan 2004
Posts: 89
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From: CO
Originally Posted by corvetteronw
Her's a pic from an 86. They are the fat metal objects on the front Y pipes.
Here is a pic of a catless front Y pipe before I installed it on my 87.
Here is a pic of a catless front Y pipe before I installed it on my 87.
Team Owner
Joined: Oct 2000
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From: 63.8% of all statistics are made up on the spot.
St. Jude Donor '08-'10
Originally Posted by Socky
Would putting out the catless Y pipes have a chane in your emissions causing a failure in an E- test?
I did this to my 90 and the answer is no it won't, IF you install a high performance main cat. I got mine from Corvette Central and my car passes emissions every year. One other thing is that this setup flows better than stock and it seems to have added a few more horses. I have no dyno numbers to prove it just a seat of the pants feeling.
Team Owner
Joined: Sep 2001
Posts: 62,160
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Originally Posted by Socky
Would putting out the catless Y pipes have a chane in your emissions causing a failure in an E- test?
precats really dont do much of the work
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Race Director
Joined: Nov 2003
Posts: 12,221
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From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Originally Posted by vader86
In any state but California you should be fine, but I would put a new main cat on with it to be sure.
precats really dont do much of the work
precats really dont do much of the work
(My question included using hi-performance cats in place of the stock system).
I asked if he was just saying this because he wasn't interested. He replied he wasn't, and that he strongly suggested leaving the stock systems alone. He explained this was happening in conjunction with newer emission standards that required better emissions from larger metropolitan areas in the U.S.
Our metropolitan paper seemed to confirm this last summer.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
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From: San Diego, Ca
The shop might be worried that someone would go here:
http://www.epa.gov/compliance/compla..._criminal.html
http://www.epa.gov/compliance/compla..._criminal.html
Team Owner
Joined: May 2001
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From: ...tearing up the highways, one state at a time™®©
Originally Posted by Socky
Would putting out the catless Y pipes have a chane in your emissions causing a failure in an E- test?
visual, yes - snifer, usually - No.
