View Poll Results: do you have cats? ever think of going catless?
i am already 
6
28.57%
thought of it/maybe
6
28.57%
no/never
9
42.86%
Voters: 21. You may not vote on this poll
catless car question
09-26-05, 09:36 PM
#2
Leave em on. I took mine off when i had the Turbo on my Camry. After that, at every light, you would smell the fumes that dont get caught in the cat. True, I was running really rich, but still, if i cruised with my windows down, I would smell like i had been doused in gas. Not good. 
09-27-05, 07:36 AM
#3
Super Moderator
Stage3, I partially agree...I know a few people who have stripped their cats down here and it smells awful...a lot of NOX contamination. I would never go completely catless. In addition, it is not a good idea to be without some backpressure when you race a car. You will lose low-end power going catless.
Leave just one cat on...and replace with a high flow cat. This is based upon my Mexican experience.
I had a horrendous experience a few weeks ago with one of my precats getting clogged.
I had to use the low quality Magna gasoline here in Mexico (long trip back from Acapulco and nearest gas station ran out of Premium), extremely high sulfur content, got a check engine light and I could feel there was something wrong. I reset the light after getting an 1154 error.
Following a trip to a muffler shop we found out the Bank 1 precat was ripped and had looked like it had burned through but the material had partially clogged my high flow cat.
I was not going to have the experience repeated ever again (especially on my dollar or peso so to speak)...so we took off both precats and installed downpipes and I replaced with another Magnaflow High Flow Cat.
I have not gotten one check engine light since...except when I go to clean my throttle body.
If you notice my signature below, I do pass Mexico City/Mexico State emissions standards...same as California's as I have a friend with a gas analyzer who checked me against the limits. My hydrocarbon count was well under 100 and at WOT I was doing 11-13 there. All other things like NOX, CO, CO2, were A-OK.
Keep in mind the gas here is not as good as quality as the stuff in the U.S., and I am above 7,000 feet here in Mexico City. So at sea level with better gas and more oxygen, I would be even doing better.
The 3-way high flow cat gave me much more power with my previous pre-cats, but with the precats off I am hauling big time.
BTW, my previous Lexus cat got hit by road debris likely a rock or something and also a check engine light...so I had to replace it.
All those precats do is keep do the work of the 3rd cat before your car warms up.
Newer Toyotas I don't think have a problem here in Mexico since they have better emissions systems (Toyota Mexico opened in April 2002), but had a diplomatic friend with a 96 Camry get his precats clogged since he wanted to save money by using Magna, which I believe is now 50 cents cheaper per gallon than Premium, which is about $3 USD/per gallon here equivalent.
Leave just one cat on...and replace with a high flow cat. This is based upon my Mexican experience.
I had a horrendous experience a few weeks ago with one of my precats getting clogged.
I had to use the low quality Magna gasoline here in Mexico (long trip back from Acapulco and nearest gas station ran out of Premium), extremely high sulfur content, got a check engine light and I could feel there was something wrong. I reset the light after getting an 1154 error.
Following a trip to a muffler shop we found out the Bank 1 precat was ripped and had looked like it had burned through but the material had partially clogged my high flow cat.
I was not going to have the experience repeated ever again (especially on my dollar or peso so to speak)...so we took off both precats and installed downpipes and I replaced with another Magnaflow High Flow Cat.
I have not gotten one check engine light since...except when I go to clean my throttle body.
If you notice my signature below, I do pass Mexico City/Mexico State emissions standards...same as California's as I have a friend with a gas analyzer who checked me against the limits. My hydrocarbon count was well under 100 and at WOT I was doing 11-13 there. All other things like NOX, CO, CO2, were A-OK.
Keep in mind the gas here is not as good as quality as the stuff in the U.S., and I am above 7,000 feet here in Mexico City. So at sea level with better gas and more oxygen, I would be even doing better.
The 3-way high flow cat gave me much more power with my previous pre-cats, but with the precats off I am hauling big time.
BTW, my previous Lexus cat got hit by road debris likely a rock or something and also a check engine light...so I had to replace it.
All those precats do is keep do the work of the 3rd cat before your car warms up.
Newer Toyotas I don't think have a problem here in Mexico since they have better emissions systems (Toyota Mexico opened in April 2002), but had a diplomatic friend with a 96 Camry get his precats clogged since he wanted to save money by using Magna, which I believe is now 50 cents cheaper per gallon than Premium, which is about $3 USD/per gallon here equivalent.
09-28-05, 03:32 AM
#6
Lexus Fanatic
In most cases you are better off leaving them on and not messing with them. The legality of removing catalylists also varies from place to place, and many areas have annual or bi-annual emission tests. If your car does not pass it cannot be registered ( the test results are transmoitted electronically to DMV ) , and you cannot get a license plate until it does. Waivers are sometimes granted if the car still doesn't pass after a certain amount of money has been spent to fix the problem...usually around $500......but that would not cover disconnected factory equipment.
09-28-05, 06:20 AM
#7
Super Moderator
mmarshall,
A lot of guys at my muffler shop were cheering me on to take off the 3rd cat, but as I mentioned I had reasons beyond just emissions for keeping it on (backpressure).
I have several American buddies with very fast sports cars living down here who have done just that and they let their American registration lapse (Mexicans don't care).
A lot of states in the U.S. require just and OBDII for 96 and newer without tailpipe. Thus, conceivably you could strip cats and if you did not get a CEL...you would be okay. However, many states also do visual inspection.
However, just to let you know we did a brief experiment with a friends RAV4 who wanted a manly exhaust and he took out the precats first, no CEL, but when he came back the following week and had the 3rd cat removed, no matter how many times we reset the CEL, it kept coming back. He bought a highflow and no problems since.
The other thing is that if you strip the precats and the cat off...you will have to worry about another legality...sound. It gets not only a bad rasp, but a very loud truck sound that will set off car alarms and the local police. I had to do some serious modification work, mucho $$$, to quiet the thing down without adding to much weight.
A lot of guys at my muffler shop were cheering me on to take off the 3rd cat, but as I mentioned I had reasons beyond just emissions for keeping it on (backpressure).
I have several American buddies with very fast sports cars living down here who have done just that and they let their American registration lapse (Mexicans don't care).
A lot of states in the U.S. require just and OBDII for 96 and newer without tailpipe. Thus, conceivably you could strip cats and if you did not get a CEL...you would be okay. However, many states also do visual inspection.
However, just to let you know we did a brief experiment with a friends RAV4 who wanted a manly exhaust and he took out the precats first, no CEL, but when he came back the following week and had the 3rd cat removed, no matter how many times we reset the CEL, it kept coming back. He bought a highflow and no problems since.
The other thing is that if you strip the precats and the cat off...you will have to worry about another legality...sound. It gets not only a bad rasp, but a very loud truck sound that will set off car alarms and the local police. I had to do some serious modification work, mucho $$$, to quiet the thing down without adding to much weight.
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09-28-05, 04:28 PM
#8
Lexus Fanatic
OK.....I see that you are in Mexico, where American Federal and State emission and registration laws don't apply. ( I'm sorry I didn't notice that before). I have no idea what Mexican laws are on removing catalysts...if there are any at all. I do know Mexico City has some of the worst air on the planet and a lot of gas stations in Mexico ( not all, of course ) sell junk fuel.
OK...I guess whatever works best for you and your car.
OK...I guess whatever works best for you and your car.
09-28-05, 07:36 PM
#9
Super Moderator
mmarshall,
Don't worry about it.
I don't agree with my sports car buddies who are ditching their cats just because they are in Mexico.
The air sucks bad enough down here and no reason to add to it. The power gain (unlike what the muffler shop was claiming like 10 hp) is less than 5 hp and you can lose low-end power.
The day that we did the pre-cat removal, I did (as most of the RX forum knows) take my car to the track and got an 18.177 (personal record).
However, I have been unable to hit it since. Thus, it really does not do as much, I think the ECM must have adjusted accordingly. Quite OK.
I told myself that if my emissions readings were even close to the Mexico City limits (they weren't before) or if a CEL popped on that could not be reset after cutting the precats (but using a high flow cat in place of the regular cat), I would then stick in two high flow cats in place of the precats.
To my surprise, the only thing that was a little bit higher (but not by much and only apparent at idle but not when I gave it some gas) was hydrocarbons. However, being at high altitude and with gas that does not burn as well as the stuff in the U.S., this was obvious. Again, no check engine light to speak off. Another advantage, I have gotten 2 more MPG.
Speaking of Mexican law, it is actually local Mexico City and State of Mexico law (two separate regions) that are similar to U.S. and state law, if the cat comes off, it must be replaced. However, there is nothing regarding precats, only that you need to pass emissions. Again, foreign-plated vehicles have no obligation to this (same if a Mexican came into Texas and lived and worked there with their Mexican car).
The new 3 way high flow cat ALMOST does the work work of the original cat and the two precats, but not quite (or we shall sea at sea level and in the U.S.).
The worst thing I was worrying about was the raspy and loud noise, but it is quiet now.
Don't worry about it.
I don't agree with my sports car buddies who are ditching their cats just because they are in Mexico.
The air sucks bad enough down here and no reason to add to it. The power gain (unlike what the muffler shop was claiming like 10 hp) is less than 5 hp and you can lose low-end power.
The day that we did the pre-cat removal, I did (as most of the RX forum knows) take my car to the track and got an 18.177 (personal record).
However, I have been unable to hit it since. Thus, it really does not do as much, I think the ECM must have adjusted accordingly. Quite OK.
I told myself that if my emissions readings were even close to the Mexico City limits (they weren't before) or if a CEL popped on that could not be reset after cutting the precats (but using a high flow cat in place of the regular cat), I would then stick in two high flow cats in place of the precats.
To my surprise, the only thing that was a little bit higher (but not by much and only apparent at idle but not when I gave it some gas) was hydrocarbons. However, being at high altitude and with gas that does not burn as well as the stuff in the U.S., this was obvious. Again, no check engine light to speak off. Another advantage, I have gotten 2 more MPG.
Speaking of Mexican law, it is actually local Mexico City and State of Mexico law (two separate regions) that are similar to U.S. and state law, if the cat comes off, it must be replaced. However, there is nothing regarding precats, only that you need to pass emissions. Again, foreign-plated vehicles have no obligation to this (same if a Mexican came into Texas and lived and worked there with their Mexican car).
The new 3 way high flow cat ALMOST does the work work of the original cat and the two precats, but not quite (or we shall sea at sea level and in the U.S.).
The worst thing I was worrying about was the raspy and loud noise, but it is quiet now.
Last edited by Lexmex; 09-28-05 at 07:42 PM.
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