Cats Have Been Deleted (Pics)
- Thread starter v10enomous
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Viper Scot
Viper Owner
But the popping and banging you get coming off throttle going down through the gears is unburnt fuel igniting in the exhaust I thought? That little bit of fuel that goes through the injectors before the exhaust valves shut when you come off throttle?
v10enomous
Enthusiast
There are millions upon millions of 4 stroke internal combustion engines in all types of applications that do not have catalytic converters. IMO they are a government mandated compromise that actually just convert one type of emission for another. Catalytic converters have always been of questionable value and they are certainly not a necessity... The benefits of reducing the heat on a Viper outweigh what has always been a debatable benefit IMO.
Catalytic Converters – To Remove Or Not To Remove - Firebird Nation
Catalytic Converters – To Remove or Not to Remove
Written By Robert Forney
As the catalytic converter debate rages on, I have decided to take a hard look at the research from an unbiased position. Many claim that removing the Cat will increase horsepower substantially, and others suggest that it will lead to increased pollution. Some even suggest that it does nothing for pollution. After looking at the research I found a lot of surprising facts about the little catalytic converter. I have created this article to share with you what I found in my research.
What is a catalytic converter and what does it do?
I am not going to get technical in describing the intricacies of a catalytic converter; I am only going to give you a quick overview of what it is and what it does. If you already know this information, skip this section and move on to the next one.
A catalytic converter looks like a small muffler. Modern catalytic converters have a honey comb shaped core (called a monolith) that the hot gasses pass through. As the gasses pass through the honeycomb core, the hydrocarbon, carbon monoxide, and nitrogen oxide are combined with the noble metals platinum, palladium, and rhodium. This process changes the chemical structure of the polluting gasses into a non-polluting form and therefore reduces these pollutants.
Does removing the catalytic converter increase horsepower substantially?
The main complaint auto enthusiasts have regarding the catalytic converter is that it increases back pressure and decreases the horsepower. But, is this concern warranted? You may be surprised to learn that modern catalytic converters flow very efficiently.
After researching this topic a little, I found that a catalytic converter reduces horsepower on a stock LT1 350 by only 4 to 5 horsepower. This is according to extensive dyno testing done by John Lingenfelter. Well, what about high performance engines, isn’t this what they complain about? Doesn’t it just kill the horsepower on a high performance engine? Again, according to the same source, a 500 horsepower engine will lose about 12 to 14 horsepower from a catalytic converter. In addition, dyno testing performed by David Vizard, the author of “How To Build Horsepower”, also backs up this research. So is it worth taking off a catalytic for a few horsepower. I think not. As you can see, it does not reduce horsepower substantially and has a negligible effect on HP.
Does the catalytic converter decrease pollution?
Again, you may be surprised by what I have uncovered when researching this topic. The answer is yes and no. You are probably wondering how that can be. The answer is that it reduces one kind of pollution while at the same time it is contributing to another type of pollution.
According to the research(1), the catalytic converter does a very good job at eliminating the pollutants it was designed to eliminate. But, there is an untold side effect of the catalytic converter. According to the research (2,3,4,5), those same Noble metals (platinum, palladium, and rhodium) that are used to convert the HC, Co, and NOx are now showing up in our environment and the effects on health are not yet known. Once again we see that there are two sides to every coin.
Conclusion:
From this article there are a few conclusions we can draw. First of all, I don’t think it is worth removing the catalytic converter for only a few horsepower. In addition, it is a federal violation of the law to do so, and for that reason alone it should be left in place. It will not increase the horsepower to any noticeable degree. It does a good job a removing the pollutants it is designed to remove, but it increases other pollutants to which we do not know the consequences.
So the debate rages on, but I think the debate should change its focus. Since it does not hurt HP by any noticeable degree, we should ask what type of pollution is more dangerous for the earth and living creatures on earth, and if there is a better way we can remove pollution from automobile exhaust.
Catalytic Converters – To Remove Or Not To Remove - Firebird Nation
Catalytic Converters – To Remove or Not to Remove
Written By Robert Forney
As the catalytic converter debate rages on, I have decided to take a hard look at the research from an unbiased position. Many claim that removing the Cat will increase horsepower substantially, and others suggest that it will lead to increased pollution. Some even suggest that it does nothing for pollution. After looking at the research I found a lot of surprising facts about the little catalytic converter. I have created this article to share with you what I found in my research.
What is a catalytic converter and what does it do?
I am not going to get technical in describing the intricacies of a catalytic converter; I am only going to give you a quick overview of what it is and what it does. If you already know this information, skip this section and move on to the next one.
A catalytic converter looks like a small muffler. Modern catalytic converters have a honey comb shaped core (called a monolith) that the hot gasses pass through. As the gasses pass through the honeycomb core, the hydrocarbon, carbon monoxide, and nitrogen oxide are combined with the noble metals platinum, palladium, and rhodium. This process changes the chemical structure of the polluting gasses into a non-polluting form and therefore reduces these pollutants.
Does removing the catalytic converter increase horsepower substantially?
The main complaint auto enthusiasts have regarding the catalytic converter is that it increases back pressure and decreases the horsepower. But, is this concern warranted? You may be surprised to learn that modern catalytic converters flow very efficiently.
After researching this topic a little, I found that a catalytic converter reduces horsepower on a stock LT1 350 by only 4 to 5 horsepower. This is according to extensive dyno testing done by John Lingenfelter. Well, what about high performance engines, isn’t this what they complain about? Doesn’t it just kill the horsepower on a high performance engine? Again, according to the same source, a 500 horsepower engine will lose about 12 to 14 horsepower from a catalytic converter. In addition, dyno testing performed by David Vizard, the author of “How To Build Horsepower”, also backs up this research. So is it worth taking off a catalytic for a few horsepower. I think not. As you can see, it does not reduce horsepower substantially and has a negligible effect on HP.
Does the catalytic converter decrease pollution?
Again, you may be surprised by what I have uncovered when researching this topic. The answer is yes and no. You are probably wondering how that can be. The answer is that it reduces one kind of pollution while at the same time it is contributing to another type of pollution.
According to the research(1), the catalytic converter does a very good job at eliminating the pollutants it was designed to eliminate. But, there is an untold side effect of the catalytic converter. According to the research (2,3,4,5), those same Noble metals (platinum, palladium, and rhodium) that are used to convert the HC, Co, and NOx are now showing up in our environment and the effects on health are not yet known. Once again we see that there are two sides to every coin.
Conclusion:
From this article there are a few conclusions we can draw. First of all, I don’t think it is worth removing the catalytic converter for only a few horsepower. In addition, it is a federal violation of the law to do so, and for that reason alone it should be left in place. It will not increase the horsepower to any noticeable degree. It does a good job a removing the pollutants it is designed to remove, but it increases other pollutants to which we do not know the consequences.
So the debate rages on, but I think the debate should change its focus. Since it does not hurt HP by any noticeable degree, we should ask what type of pollution is more dangerous for the earth and living creatures on earth, and if there is a better way we can remove pollution from automobile exhaust.
I can only speak from my personal experience. At 580 RWHP I gained 5hp going catless. Honestly that's not much of a scientific result either, as it was on different days and different dyno's. What I have to admit is that 25 years ago growing up in Northridge, CA I couldn't see the mountain that was five miles away during the summer. The sky was the nastiest shade of brown that you could imagine. I can tell you that I have not seen one single day that's even close to that in the past five years.
As far as the Viper's concerned, the Factory cats are amazingly good cats, but admittedly transfer way too much heat into the side sills. A quality set of metal matrix cats will do a decent job of cleaning exhaust emissions (though not nearly as good as the stock cats) and should last about 10 - 20k miles. The bonus with the aftermarket cats is that their OD is much smaller than the factoty cats, thus no contact between the heat shield and cat.
As far as the Viper's concerned, the Factory cats are amazingly good cats, but admittedly transfer way too much heat into the side sills. A quality set of metal matrix cats will do a decent job of cleaning exhaust emissions (though not nearly as good as the stock cats) and should last about 10 - 20k miles. The bonus with the aftermarket cats is that their OD is much smaller than the factoty cats, thus no contact between the heat shield and cat.
runin1320
Viper Owner
I finally installed my high-flow cats! 
Going to put in stainless or "real" high-flow cats in the Spring. Just needed to give it a little authority right now. Got ~$50 into it.
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Going to put in stainless or "real" high-flow cats in the Spring. Just needed to give it a little authority right now. Got ~$50 into it.
v10enomous
Enthusiast
Bet she sounds nice
I finally installed my high-flow cats!
You must be registered for see images attach
You must be registered for see images attach
Going to put in stainless or "real" high-flow cats in the Spring. Just needed to give it a little authority right now. Got ~$50 into it.
Fatboy 18
Enthusiast
Great pics And I'm really liking that price too 
I was thinking of doing a similar thing, I have the Bellanger cat back system on my car, so I don't have that big silencer in the side sill
And I'm really liking that price too I was thinking of doing a similar thing, I have the Bellanger cat back system on my car, so I don't have that big silencer in the side sill
cyaford
Enthusiast
CROM
Viper Owner
I had no cats at one point on my 98GTS and it was too damned loud, and I like loud. But our loud is not clean like a 4.6L Mustang, it's more like two 5 cylinders having a ******* contest. You could hear me a mile away, but I don't think the neighbors appreciated me shaking their windows as I drove through the neighborhood at midnight. I have one of the older Borla exhaust systems, which is really a 2.5" system. I now have 2.5" metal RT cats and the car sounds pretty good, and is still relatively loud. I have stock headers. The side sills remain pretty cool with the RTs. Much cooler than stock..
I'm anal (didn't want to hack up my stock pipes) so I have several sets of stock cats and downpipes that I used for my straight pipe and new cat setup, but to go straight pipes is really cheap. You need a couple lengths of 2.5 or 3" pipe (flared at each end to match the appropriate input/output pipe diameters) some clamps, and a reciprocating saw. It's that easy. I chose to cut my pipes OFF the vehicle, so I had to pull off the header down pipe (that the cat is attached to). Don't forget to order set of new band clamps from Tator if you do that
Best Viper exhaust I ever heard was a full Bellanger system (Headers/Cats/Exhaust)
I'm anal (didn't want to hack up my stock pipes) so I have several sets of stock cats and downpipes that I used for my straight pipe and new cat setup, but to go straight pipes is really cheap. You need a couple lengths of 2.5 or 3" pipe (flared at each end to match the appropriate input/output pipe diameters) some clamps, and a reciprocating saw. It's that easy. I chose to cut my pipes OFF the vehicle, so I had to pull off the header down pipe (that the cat is attached to). Don't forget to order set of new band clamps from Tator if you do that
Best Viper exhaust I ever heard was a full Bellanger system (Headers/Cats/Exhaust)
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