Going cat-less.
Thread Starter
Race Director
Joined: Feb 2003
Posts: 18,484
Likes: 1
From: Everyday you must choose between the pain of discipline and the pain of regret. Fredericktown, OH
Going cat-less.
My cats have really started to stink and I think it is time to replace or remove.
If I go cat-less, do I just need to get the 02 sims for the rear sensors (this is a '96) to keep the computer happy?
Anyone have real world dyno numbers on going cat-less?
I am not in an emissions tested area, so that is not a concern.
If I did decide to replace the cats, ay statistics on which aftermarket company performs the best?
Thanks!
If I go cat-less, do I just need to get the 02 sims for the rear sensors (this is a '96) to keep the computer happy?
Anyone have real world dyno numbers on going cat-less?
I am not in an emissions tested area, so that is not a concern.
If I did decide to replace the cats, ay statistics on which aftermarket company performs the best?
Thanks!
Safety Car
Joined: Sep 2000
Posts: 3,524
Likes: 4
From: Hinckley Ohio
You might want to consider high flow cats..Dynatech $165ea at Summit....Pretty sure Rottie can beat this price
http://store.summitracing.com/defaul...=egnsearch.asp
They work real good with long tube headers
If you look at the high flow cats you will see that you would loose very little performance compared to a straight pipe....much better than stock cats....
I THINK to do nothing but remove the cats would gain very little, probably less than 10hp, but that is just a quess....
Have you thrown a code????
I would check with Bryan about the need for simulators if you do decide to remove the Cats..
http://store.summitracing.com/defaul...=egnsearch.asp
They work real good with long tube headers
If you look at the high flow cats you will see that you would loose very little performance compared to a straight pipe....much better than stock cats....
I THINK to do nothing but remove the cats would gain very little, probably less than 10hp, but that is just a quess....
Have you thrown a code????
I would check with Bryan about the need for simulators if you do decide to remove the Cats..
Last edited by LT4BUD; Jul 10, 2005 at 10:47 AM.
Burning Brakes
Joined: Feb 2000
Posts: 1,247
Likes: 2
From: Parker, Colorado, USofA
Contrary to popular belief, cats DO positively affect your emissions. (Well, you CAR'S emissions)
I ran with an offroad pipe for awhile while getting the car tuned...I had to fire the car up and IMMEDIATELY leave the garage, the fumes were NASTY.
I also noticed when I put the cat back on, I gained some low end torque from the backpressure. I may have lost something on the top end, but I can't be sure.
I ran with an offroad pipe for awhile while getting the car tuned...I had to fire the car up and IMMEDIATELY leave the garage, the fumes were NASTY.
I also noticed when I put the cat back on, I gained some low end torque from the backpressure. I may have lost something on the top end, but I can't be sure.
Race Director
Joined: Jan 2002
Posts: 12,261
Likes: 85
From: O'Fallon Missouri
I'm running the Dynatech PowerCats. You can get them a little cheaper at rpmoutlet. They offer a 10% discount and free shipping.
http://rpmoutlet.com/powercat.htm
http://rpmoutlet.com/powercat.htm
Thread Starter
Race Director
Joined: Feb 2003
Posts: 18,484
Likes: 1
From: Everyday you must choose between the pain of discipline and the pain of regret. Fredericktown, OH
Originally Posted by LT4BUD
You might want to consider high flow cats..Dynatech $165ea at Summit....Pretty sure Rottie can beat this price
http://store.summitracing.com/defaul...=egnsearch.asp
They work real good with long tube headers
If look at the high flow cats you will see that you would loose very little performance compared to a straight pipe....much better than stock cats....
I THINK to do nothing but remove the cats would gain very little, probably less than 10hp, but that is just a quess....
Have you thrown a code????
I would check with Bryan about the need for simulators if you do decide to remove the Cats..
http://store.summitracing.com/defaul...=egnsearch.asp
They work real good with long tube headers
If look at the high flow cats you will see that you would loose very little performance compared to a straight pipe....much better than stock cats....
I THINK to do nothing but remove the cats would gain very little, probably less than 10hp, but that is just a quess....
Have you thrown a code????
I would check with Bryan about the need for simulators if you do decide to remove the Cats..
I haven't thrown a code, but they do stink and have had comments from a friend driving behind me that it really stinks.
Thanks for the link. I was thinking they would be more $.
Burning Brakes
Joined: Mar 2005
Posts: 1,042
Likes: 0
You may have a rich condition causing that smell,you may need to check your A/F ratio with a scanner.if your cats are bad,YOU WILL KNOW,there will be a loss of power,and if they are really bad,you may even feel heat coming from the floorboard.As far as going catless,I had mine removed and put 2 pipes instead about a month ago,(got alot of flack for it) and I LOST some low end throttle response,and didnt feel hardly any gain up top, compared to the 113k mi cats I had on.(It does sound better though)If I had to do it again,I would have put highflows on.I had a Carsound on my T/A which I really liked.
Thread Starter
Race Director
Joined: Feb 2003
Posts: 18,484
Likes: 1
From: Everyday you must choose between the pain of discipline and the pain of regret. Fredericktown, OH
The car has been on a chassis dyno and the A/F looked really good. I do suspect the beginning of the end for the cats.
No biggie.
Thanks!
No biggie.
Thanks!
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Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
If you are thinking about replacing the stock cats here are some interesting flow numbers from an old Forum post:
Mfg................P/N........CFM.......Comments
GM LS1...........RH side...220........Stock cat in 2000
GM LS1...........LH side...250........Stock cat in 2000
Random Tech...81300....327........3"
Catco.............6907......365........3 "
Carsound.........94109....400........3"
Random Tech...70300....535........3"
Since a SBC requires about 2.2 cfm for each HP we begin to see back pressure losses, it is evident that a 300 chp motor (requiring 660 cfm) with a single cat is being restricted by the exhaust system. At 470 cfm total, even the stock cats were inadequate.
Mfg................P/N........CFM.......Comments
GM LS1...........RH side...220........Stock cat in 2000
GM LS1...........LH side...250........Stock cat in 2000
Random Tech...81300....327........3"
Catco.............6907......365........3 "
Carsound.........94109....400........3"
Random Tech...70300....535........3"
Since a SBC requires about 2.2 cfm for each HP we begin to see back pressure losses, it is evident that a 300 chp motor (requiring 660 cfm) with a single cat is being restricted by the exhaust system. At 470 cfm total, even the stock cats were inadequate.
Le Mans Master
Joined: Feb 1999
Posts: 6,470
Likes: 2
From: levittown pa. usa Even a bad day with my `Vette, is better than a good day at work
St. Jude Donor '10
UHOH!---- Bogus must be takin a nap----
Even if you don`t have emission testing in your area, keeping the air we breathe a little cleaner is a very worthy cause
Even if you don`t have emission testing in your area, keeping the air we breathe a little cleaner is a very worthy cause
Race Director
Joined: Jan 2002
Posts: 12,261
Likes: 85
From: O'Fallon Missouri
A friend of mine pulled the cats off his 94 Vette, for some reason he removes the cats off all of his vehicles. However, that car's exhaust smelled so bad on startup, it was embarrasing.
Burning Brakes
Joined: Jan 2002
Posts: 1,228
Likes: 1
From: Dallas Texas
If a cheap 3" high flow bullet cat is what you're after, get a set of cats from Pypes... $70 each and flow 450 cfm. They also work really well since I passed washington state emissions with flying colors. link
Here they are on my car mated to EM headers and 3" exhaust I made myself (they are SMALL!):
Here they are on my car mated to EM headers and 3" exhaust I made myself (they are SMALL!):
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Originally Posted by kenv
UHOH!---- Bogus must be takin a nap----
Even if you don`t have emission testing in your area, keeping the air we breathe a little cleaner is a very worthy cause
Even if you don`t have emission testing in your area, keeping the air we breathe a little cleaner is a very worthy cause
I would go high flow... the performance is good, and the back pressure will help maintain performance...
While keeping your air clean.
What people don't understand, just because you don't have emissions testing, it is still against the law (federal) to remove cats. And who says you won't get emissions testing? Then you would be sooo screwed.
Drifting
Joined: Aug 2004
Posts: 1,400
Likes: 0
From: Oceansaide CA
Well the fact of the matter is, it's not like some areas simply believe that clean air and water is a luxury that we could do without. No, the reason you don't have to test, is because the gov't trusts you to leave all the emissions stuff in place, and be a good little citizen. If you have the cash, by all means, go get a cat. You don't have to test now, so don't ruin it for yourself. We have to test here because of all the geniuses who figured they'd beat the system, and yes, it's a pain in the ***.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
If the CARB is only about providing clean air in a logical manner then why do they not permit mods which have no detremental effect on air quality??
For example, if you install true duals on your Vette (or on any car) and it passes the sniffer why should it matter how that is accomplished! Hmm, of course it couldn't have to do with the part mfg not caughing up the $$ to pass their special test sequence could it...naaaah.
For example, if you install true duals on your Vette (or on any car) and it passes the sniffer why should it matter how that is accomplished! Hmm, of course it couldn't have to do with the part mfg not caughing up the $$ to pass their special test sequence could it...naaaah.