By-Pass Cats? Yes or No?
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
Re: By-Pass Cats? Yes or No? (grape8)
A guy in SW FL with true duals behind his L98 made runs at the strip with RT cats and without and no diff; he still ran 12.0xx sec. Of course he had TPIS headers too to tune the exhaust flow.
Race Director
Joined: May 2001
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Re: By-Pass Cats? Yes or No? (65Z01)
There are many ways to look at it.
If your stock cats are healthy you probably won't see much difference. If you gut them you could see a loss because of increased backpressure caused by increased turbulence. You can avoid this by putting a straight pipe through the gutted cat to make it act like a straight pipe.
Headers can give a very nice increase as well. The problem is that it's harder to rig cats onto a set of full out long tube headers. Not impossible, just more difficult. Most people who have put a set of high flow cats on their headers haven't noticed any substantial power loss.
So what I guess I'm trying to say is that healthy cats are not a huge exhaust restriction. I don't run them because I have long tube headers. I could, but it would be very costly. As such we don't have local emissions checks, I'm not going to worry about it.
If your stock cats are healthy you probably won't see much difference. If you gut them you could see a loss because of increased backpressure caused by increased turbulence. You can avoid this by putting a straight pipe through the gutted cat to make it act like a straight pipe.
Headers can give a very nice increase as well. The problem is that it's harder to rig cats onto a set of full out long tube headers. Not impossible, just more difficult. Most people who have put a set of high flow cats on their headers haven't noticed any substantial power loss.
So what I guess I'm trying to say is that healthy cats are not a huge exhaust restriction. I don't run them because I have long tube headers. I could, but it would be very costly. As such we don't have local emissions checks, I'm not going to worry about it.
8th Gear
Joined: Aug 2002
Posts: 8
Likes: 0
From: Kennesaw GA
Re: By-Pass Cats? Yes or No? (grape8)
I wouldn't do it. 3 reasons why:
1. Believe it or not, you will loose torque.
2. You will get an aweful smell because the cats are not burning any of the toxic gases being produced from the engine.
3 You will be releasing a lot of harmful emisions. And that is not good.
Just my .02
JC
1. Believe it or not, you will loose torque.
2. You will get an aweful smell because the cats are not burning any of the toxic gases being produced from the engine.
3 You will be releasing a lot of harmful emisions. And that is not good.
Just my .02
JC
Race Director
Joined: Feb 2002
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From: Honolulu, HI
Re: By-Pass Cats? Yes or No? (Nathan Plemons)
depending on the year of the car and the state you're in. You could qualify for show car insurance which grants you the ability to get an emissions waiver. Then you can do what you want :D
your insurance will also be cheaper, you can set the amount of the cars worth instead of relying on the "book" value (which is typically lower than the amount of any mods) and the mileage is pretty gratuitous. between 5000 and 7500 miles a year allowable.
your insurance will also be cheaper, you can set the amount of the cars worth instead of relying on the "book" value (which is typically lower than the amount of any mods) and the mileage is pretty gratuitous. between 5000 and 7500 miles a year allowable.
Melting Slicks
Joined: Jan 2000
Posts: 3,418
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From: NW Chicago Suburbs
Re: By-Pass Cats? Yes or No? (JC'S01COBRA)
1. Believe it or not, you will loose torque.
Eric
Team Owner
Joined: Dec 2000
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From: SE NY
Cruise-In II Veteran
Re: By-Pass Cats? Yes or No? (grape8)
My bad, now I see you have an LT1 with dual cats, not an L98 with main cat and two pre-cats.
In this case I would suggest a pair of hi-flow cats as a mild upgrade; better would be full-length headers. You could always add a pair of hi-flow bullet cats for emissions if needed.
In this case I would suggest a pair of hi-flow cats as a mild upgrade; better would be full-length headers. You could always add a pair of hi-flow bullet cats for emissions if needed.
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Race Director
Joined: May 2001
Posts: 14,165
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Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: By-Pass Cats? Yes or No? (Nathan Plemons)
"http://www.junkscience.com/news2/catalyt.htm"
Bless those environmentalists; another chrisis to work on. :rolleyes:
Not to worry though, the next huge metior will hit before global warming reaches the intolerable point and solve the problelm, nature's way. :lol:
Bless those environmentalists; another chrisis to work on. :rolleyes:
Not to worry though, the next huge metior will hit before global warming reaches the intolerable point and solve the problelm, nature's way. :lol:
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: By-Pass Cats? Yes or No? (Siveck)
It's the same thing as diesels. People hate them because they produce nasty exhaust. Too bad they run cleaner than gasoline engines.
I've done my part to reduce global warming. Hooker part number 2151
[Modified by Nathan Plemons, 3:57 PM 8/16/2002]
I've done my part to reduce global warming. Hooker part number 2151
[Modified by Nathan Plemons, 3:57 PM 8/16/2002]
8th Gear
Joined: Aug 2002
Posts: 8
Likes: 0
From: Kennesaw GA
Re: By-Pass Cats? Yes or No? (silver & red CE)
Hey silver & red CE, no flame intended, but do you believe eveything you read? I have seen actual dyno results, not read it in an article. I read in the Mustang and fast ford magazine they hit 13.3 at 101 with a completely stock convertible 2001 cobra. That is near impossible. I know a guy who can drive his 01 cobra coup abd he is hitting 311 rwhp and his best time is 13.39. Again no flame intended. I would suggest going with high flow cats. 2 cats are better than 4 if that is what the vett's have. That is for hp.
JC :D
JC :D
Race Director
Joined: May 2001
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Re: By-Pass Cats? Yes or No? (JC'S01COBRA)
LT1 vettes have 2. Only Fords burn so dirty that they must have 4 or 5 cats :)
Seriously there is a little power to be had, but very little. Unless your cat is clogged or you're putting headers in it's really not worth the effort of removing them.
Seriously there is a little power to be had, but very little. Unless your cat is clogged or you're putting headers in it's really not worth the effort of removing them.
Racer
Joined: Apr 2002
Posts: 389
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From: Micco FL
Re: By-Pass Cats? Yes or No? (JC'S01COBRA)
Ditto on the overzelous environmentalist. In the misguided cause of ridding this planet of a plague (human kind) they have reeked havoc on industry. There must be an equitable balance between environmental protection and our rights for free enterprise, places to live, and pursuit of happiness. All that aside here is another view on removing the catalytic converter(s).
OK so there is a big debate on to remove or not and there have been many interesting and viable arguments. How about this…should you decide to sell the car you have now limited the places where the car is legal.
OK so there is a big debate on to remove or not and there have been many interesting and viable arguments. How about this…should you decide to sell the car you have now limited the places where the car is legal.
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: By-Pass Cats? Yes or No? (PTz-92-LT1)
…should you decide to sell the car you have now limited the places where the car is legal.
Melting Slicks
Joined: Jan 2000
Posts: 3,418
Likes: 1
From: NW Chicago Suburbs
Re: By-Pass Cats? Yes or No? (JC'S01COBRA)
Hey silver & red CE, no flame intended, but do you believe eveything you read....
Eric
Melting Slicks
Joined: Aug 2000
Posts: 2,388
Likes: 42
From: Murrysville PA
Re: By-Pass Cats? Yes or No? (silver & red CE)
I'm not a tree hugging hippie by any stretch. But I feel as if we have a responsibilty to use a technology that is healthier for the environment. For me gaining a few extra HP is not worth it. Lets face it, have you ever driven behind an old car and choked on his or her exhaust smell?
Racer
Joined: Jul 2002
Posts: 412
Likes: 0
From: corvallis or
Re: By-Pass Cats? Yes or No? (89vette)
DONT completly blame the converter or lack of one for the nasty smells or high emmission output. Both smells and emissions are the byproduct of unburned fuel the result of poor combustion. That is the whole purpose of a converter to clean up the leftovers. With OE exhaust and no engine mods my HC count was 4ppm @idle 49ppm @steady 2000rpm. After stat, rockers,and hollowed cat, HC count went to 18ppm@idle and 35ppm@2000 oh by the way dont smell anything either.