Removing Cat
03-09-2004, 05:47 PM
#22
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How's this for performance: 
"Various Catalytic converters were tested. All the "Hi-Flow" style units gain about 1% horsepower. Removing the Catalytic Converter results in about a 3% HP gain, but has a loss of torque on engines 3.0L and less."
"Various Catalytic converters were tested. All the "Hi-Flow" style units gain about 1% horsepower. Removing the Catalytic Converter results in about a 3% HP gain, but has a loss of torque on engines 3.0L and less."
03-09-2004, 05:48 PM
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Originally Posted by My99
Yes, my favorite mod, of which so many are jealous. 
and work up some of that additive for your fuel tank. 
03-09-2004, 05:52 PM
#24
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Originally Posted by MTL_4runner
How's this for performance:
"Various Catalytic converters were tested. All the "Hi-Flow" style units gain about 1% horsepower. Removing the Catalytic Converter results in about a 3% HP gain, but has a loss of torque on engines 3.0L and less."
"Various Catalytic converters were tested. All the "Hi-Flow" style units gain about 1% horsepower. Removing the Catalytic Converter results in about a 3% HP gain, but has a loss of torque on engines 3.0L and less."
03-09-2004, 05:52 PM
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Originally Posted by MTL_4runner
How's this for performance:
"Various Catalytic converters were tested. All the "Hi-Flow" style units gain about 1% horsepower. Removing the Catalytic Converter results in about a 3% HP gain, but has a loss of torque on engines 3.0L and less."
"Various Catalytic converters were tested. All the "Hi-Flow" style units gain about 1% horsepower. Removing the Catalytic Converter results in about a 3% HP gain, but has a loss of torque on engines 3.0L and less."
03-09-2004, 05:54 PM
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Its also illegal to speed, but thats not stoppen people.
03-09-2004, 05:55 PM
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Originally Posted by My99
horsemess, horsemess, 100X horsemess. Back-pressure being necessary is BS and I'll argue it till the day I die.
Anyhow, we all have our drivers licenses hopefully by the time we get here and theoretically, being fairly technically inclined as a lot of us seem to be on this board, would know what a catalytic converter is and why it's there. When someone talks about their stupid clear corner lamps or something people don't go yelling at them about how they're illegal in a lot of cities. He asked for info, and if you told him in a civil manner that that's illegal, as just an FYI, it wouldn't have been such a big issue.
Peace.
Anyhow, we all have our drivers licenses hopefully by the time we get here and theoretically, being fairly technically inclined as a lot of us seem to be on this board, would know what a catalytic converter is and why it's there. When someone talks about their stupid clear corner lamps or something people don't go yelling at them about how they're illegal in a lot of cities. He asked for info, and if you told him in a civil manner that that's illegal, as just an FYI, it wouldn't have been such a big issue.
Peace.
http://auto.howstuffworks.com/framed...austtheory.htm
I know people will say their butt-dyno begs to differ, but I say their ear-dyno is fooling them. Louder does not automatically equal faster.
Aaron
03-09-2004, 05:55 PM
#28
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[Speeding will cost a few week's salary if you factor in higher insurance premiums, removing the cat converter is a federal offense with a prison term. Just an FIY.]
ive reconsidered guys trust me
ive reconsidered guys trust me
Last edited by fooddude; 03-09-2004 at 05:57 PM.
03-09-2004, 05:59 PM
#29
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Originally Posted by fooddude
[Speeding will cost a few week's salary if you factor in higher insurance premiums, removing the cat converter is a federal offense with a prison term. Just an FIY.]
ive reconsidered guys trust me
ive reconsidered guys trust meLOL woohoo Sulphur smell lovin cat haters 0
cop wanna be formerly flamed all to hell sulphur smell haters 1
we win we win
03-09-2004, 06:03 PM
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I talked to a motor officer and he says that for strictly off-road use you can do just about anything. HOWEVER... most offroad and state parks require an exhaust complete with cat.
03-09-2004, 06:03 PM
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well it wasn't too bad with my 31's but noticable. Now that I've up'd to 34's and not regeared it's a pain when trying to crawl and not kill it.
dang man you read that quick I just deleted that post because I figured you already had enough feed back on it.
dang man you read that quick I just deleted that post because I figured you already had enough feed back on it.
Last edited by OicnaiC; 03-09-2004 at 06:05 PM.
03-09-2004, 06:13 PM
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we do a lot of illegal things to our trucks/cars but trust me, the smell you get from removing the cat is unbarable. you wouldnt have be able to open your back windows if you did that and your backend will turn black and tarry quick wich would be a pain to get off. No real gain on hp because you will lose torque and only gain a little bit on top end, On a TRUCK engine which are designed to have more torque that would be senseless to do . By all means experience it yourself if you have to, but those are what you'll get out of removing the cat. just my 2 cents
03-09-2004, 06:38 PM
#34
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Originally Posted by BigBadBlue
LOL woohoo Sulphur smell lovin cat haters 0
cop wanna be formerly flamed all to hell sulphur smell haters 1
we win we win
cop wanna be formerly flamed all to hell sulphur smell haters 1
we win we win
This guy's in his own world, I lost (or did he?) comprehension of what his point was about 3 posts back.As far as backpressure goes, here's what I believe:
No engine wants back pressure. Where the myth starts though, is someone going with exhaust that is so large, it kills the exhaust velocity and motor is not able to effectively scavange the exhaust out of the way, until higher RPMs.
Go as large as you can without loosing exhaust velocity, for the most power gains. A catalytic converter is definitely a MASSIVE restriction. Although, I'm not advocating taking them off, especially on our vehicles, I do have first hand experience that tells me a cat robs more power than a muffler.
And where do you guys get off saying without a cat your exhaust stinks? It's a catalytic converter that causes the sulphur smell.
Last edited by My99; 03-09-2004 at 06:39 PM.
03-09-2004, 07:11 PM
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BBB has his moments but, I would draw the line at having his own world. I am thinking parallel universe or sub space demonsational plane. BBB has added more value challenging Yota members with "what if?" then most folks.
And he kind of grows on yah after a little while.
And he kind of grows on yah after a little while.
03-09-2004, 08:36 PM
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Originally Posted by My99
This guy's in his own world, I lost (or did he?) comprehension of what his point was about 3 posts back.As far as backpressure goes, here's what I believe:
No engine wants back pressure. Where the myth starts though, is someone going with exhaust that is so large, it kills the exhaust velocity and motor is not able to effectively scavange the exhaust out of the way, until higher RPMs.
Go as large as you can without loosing exhaust velocity, for the most power gains. A catalytic converter is definitely a MASSIVE restriction. Although, I'm not advocating taking them off, especially on our vehicles, I do have first hand experience that tells me a cat robs more power than a muffler.
And where do you guys get off saying without a cat your exhaust stinks? It's a catalytic converter that causes the sulphur smell.
03-09-2004, 09:05 PM
#37
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Alright, we just covered this in my Chem II class.
Here's what a cat does (straight from the book):
----------in-------------------------out
O2+CO+NO+hydrocarbons---->O2+CO2+N2+H2O
So basically the catalytic converter gets rid of the hydrocarbons, carbon monoxide, and nitrogen oxide.
I knew chemistry might come in handy for something one day.
I went with a high-flow cat on my exhaust. Since I had the muffler and the exhaust were done at the same time, I can't say how much of an effect the cat had. All I can give you is the "seat of my pants" comparison. After doing the exhaust the drive on the highway is much better. It feels as if my torque curve has been moved upward. Taking hills is much easier than it once was. Acceleration is also better. By all means it is still not comparable to the 3.4L. But it is better which is all I wanted.
Guys, just keep your cats and don't hollow them out. We need to keep this world in decent shape for our children and their children.
I also got kind of lost with BBB comments earlier.
Alright, that's my $.02.
Here's what a cat does (straight from the book):
----------in-------------------------out
O2+CO+NO+hydrocarbons---->O2+CO2+N2+H2O
So basically the catalytic converter gets rid of the hydrocarbons, carbon monoxide, and nitrogen oxide.
I knew chemistry might come in handy for something one day.
I went with a high-flow cat on my exhaust. Since I had the muffler and the exhaust were done at the same time, I can't say how much of an effect the cat had. All I can give you is the "seat of my pants" comparison. After doing the exhaust the drive on the highway is much better. It feels as if my torque curve has been moved upward. Taking hills is much easier than it once was. Acceleration is also better. By all means it is still not comparable to the 3.4L. But it is better which is all I wanted.
Guys, just keep your cats and don't hollow them out. We need to keep this world in decent shape for our children and their children.
I also got kind of lost with BBB comments earlier.
Alright, that's my $.02.
03-10-2004, 04:24 AM
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Originally Posted by amusement
BBB has his moments but, I would draw the line at having his own world. I am thinking parallel universe or sub space demonsational plane. BBB has added more value challenging Yota members with "what if?" then most folks.
And he kind of grows on yah after a little while.
And he kind of grows on yah after a little while.
03-10-2004, 06:11 AM
#39
Registered User
Originally Posted by AgRunner06
Alright, we just covered this in my Chem II class.
Here's what a cat does (straight from the book):
----------in-------------------------out
O2+CO+NO+hydrocarbons---->O2+CO2+N2+H2O
So basically the catalytic converter gets rid of the hydrocarbons, carbon monoxide, and nitrogen oxide.
I knew chemistry might come in handy for something one day.
I went with a high-flow cat on my exhaust. Since I had the muffler and the exhaust were done at the same time, I can't say how much of an effect the cat had. All I can give you is the "seat of my pants" comparison. After doing the exhaust the drive on the highway is much better. It feels as if my torque curve has been moved upward. Taking hills is much easier than it once was. Acceleration is also better. By all means it is still not comparable to the 3.4L. But it is better which is all I wanted.
Guys, just keep your cats and don't hollow them out. We need to keep this world in decent shape for our children and their children.
I also got kind of lost with BBB comments earlier.
Alright, that's my $.02.
Here's what a cat does (straight from the book):
----------in-------------------------out
O2+CO+NO+hydrocarbons---->O2+CO2+N2+H2O
So basically the catalytic converter gets rid of the hydrocarbons, carbon monoxide, and nitrogen oxide.
I knew chemistry might come in handy for something one day.
I went with a high-flow cat on my exhaust. Since I had the muffler and the exhaust were done at the same time, I can't say how much of an effect the cat had. All I can give you is the "seat of my pants" comparison. After doing the exhaust the drive on the highway is much better. It feels as if my torque curve has been moved upward. Taking hills is much easier than it once was. Acceleration is also better. By all means it is still not comparable to the 3.4L. But it is better which is all I wanted.
Guys, just keep your cats and don't hollow them out. We need to keep this world in decent shape for our children and their children.
I also got kind of lost with BBB comments earlier.
Alright, that's my $.02.
Thankyou. UP2 was 2 years and 2 majors ago for me.
The catalytic converter does not get rid of unburned fuel. There should be no unburned fuel exiting your exhaust. If there is, it will quickly ruin/clog your catalytic converter. It's purpose is to reduce carbon monoxide, ozone killer.
No worries BBB, just wasn't following some of your posts there.
03-10-2004, 08:00 AM
#40
Contributing Member
I should be prepping for my chemistry class, but I figured I ought to set a few things straight. Keep in mind that I am very much in favor of keeping cats.
Misconception 1. Your exhaust is not destroying the ozone layer that exists in the stratosphere and the troposphere. Freon (chloro-fluoro carbons) do that. So fix your leaky air conditioning systems....or better yet, convert it to the newer, supposedly safer refrigerants.
However, removing cats DOES contribute to surface ozone. Ozone (O3) is poisonous, odorless, colorless gas that attacks many different molecules. And what are cells made of? So now you see the problem, surface ozone attacks the respiratory tracts, damages alveoli and bronchial passages and contributes to increased asthma and probably allergies.
Surface ozone is created when UV rays attack the NOX and hydrocarbons that are exhausted by high-compression engines (includes diesels). At higher combustion temperatures, more NOX are produced. Which is why EGR systems...to reintroduce exhaust gases into the combustion chamber and limit the amount of fuel-air mix that can be taken in...thus lowering the combustion temperatures and pressures. High compression engines operate at higher cumbustion temperatures and pressures and in general produce more surface ozone producing NOX. I could go into the enthalpy of formation for NOX and CO but don't really have time now.
If my oldtimers disease doesn't kick in, I'll cover some of the other misconceptions later. Gotta get to class.
Just remember that the only reason we have our 4Runners is to enjoy getting out. If our outdoors is destroyed, what are we left with? Holodecks?
Misconception 1. Your exhaust is not destroying the ozone layer that exists in the stratosphere and the troposphere. Freon (chloro-fluoro carbons) do that. So fix your leaky air conditioning systems....or better yet, convert it to the newer, supposedly safer refrigerants.
However, removing cats DOES contribute to surface ozone. Ozone (O3) is poisonous, odorless, colorless gas that attacks many different molecules. And what are cells made of? So now you see the problem, surface ozone attacks the respiratory tracts, damages alveoli and bronchial passages and contributes to increased asthma and probably allergies.
Surface ozone is created when UV rays attack the NOX and hydrocarbons that are exhausted by high-compression engines (includes diesels). At higher combustion temperatures, more NOX are produced. Which is why EGR systems...to reintroduce exhaust gases into the combustion chamber and limit the amount of fuel-air mix that can be taken in...thus lowering the combustion temperatures and pressures. High compression engines operate at higher cumbustion temperatures and pressures and in general produce more surface ozone producing NOX. I could go into the enthalpy of formation for NOX and CO but don't really have time now.
If my oldtimers disease doesn't kick in, I'll cover some of the other misconceptions later. Gotta get to class.
Just remember that the only reason we have our 4Runners is to enjoy getting out. If our outdoors is destroyed, what are we left with? Holodecks?
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