cat converters? ok to remove?
Lexus Champion
Joined: Nov 2001
Posts: 3,006
Likes: 1
From: New York (NY)
Should be no problem. Just be careful with your O2 sensors (if they exist on your US cars).
Unless you are removing them permanently, then it makes it illegal in the US.
Now, here in Jakarta on the other hand..... *evil grin*
Unless you are removing them permanently, then it makes it illegal in the US.
Now, here in Jakarta on the other hand..... *evil grin*
Driver
Joined: May 2002
Posts: 102
Likes: 0
From: New York
hey Roenick7 is it really ok to drive w/o cats? I might try that and get 2 testtubes, but i thought the ECU will run the car too lean, due to the rich signal from the second set of O2 sensors. too lean=detonation but maybe engineers programed the ecu to accept this no problem.
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
Guys, lspower has a 1990 LS400 and that car only has 2 oxygen sensors, both before the cats, removing the cats will not create a problem. Now, in later engines such as ours with four o2 sensors, removing the cats will throw codes. One solution that the Corvette crowd uses are o2 simulators. These plug in and send a fake signal that all is well. A pair cost around $200.
Pole Position
Joined: Jul 2003
Posts: 2,101
Likes: 10
From: Kansas
Would MIL eliminators work on this?? I had an O/R X pipe on my 99 cobra and with the CATS off it would throw a light. MILS cost me about $50 and gave the computer the reading that the CATS were still on there. It was an easy splice and took about 10 minutes to do.
Just curious if this would work on the Lexus as well?
Red Rover
Just curious if this would work on the Lexus as well?
Red Rover
Lead Lap
Joined: Jun 2003
Posts: 437
Likes: 0
From: Massachusetts
Man I'd love to gut the cat on my es300 I bet it would make the pedal MUCH lighter 
Anyone ever do this on a ES300? Maybe I can get a donor Converter to hollow out since I don't wanna gut mine and then it's throwing codes like crazy.
Anyone ever do this on a ES300? Maybe I can get a donor Converter to hollow out since I don't wanna gut mine and then it's throwing codes like crazy.
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Pole Position
Joined: Oct 2002
Posts: 395
Likes: 0
From: North Carolina
The cat systems on the GS and even LS cars seem to be very efficient (especially multiple cat systems). Removing the cats will lean the a/f mixture on OBD II cars and probably hurt performance more than help it in a non-forced induction application (and possibly cause detonation).
I've owned two 11 second cars (OBD I) and I retained single cats on both (random technology); there was no measurable difference in 1/4 mile mph with or without the cats. There are well published tests in many performance magazines that show the HP gain from removal of a cat / cats isn't worth the pollution you're introducing into the environment.
I've owned two 11 second cars (OBD I) and I retained single cats on both (random technology); there was no measurable difference in 1/4 mile mph with or without the cats. There are well published tests in many performance magazines that show the HP gain from removal of a cat / cats isn't worth the pollution you're introducing into the environment.
Last edited by tomtnc; Aug 8, 2003 at 07:56 AM.
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Lexus Test Driver
Joined: Jan 2003
Posts: 1,250
Likes: 1
From: Georgia
Originally posted by tomtnc
The cat systems on the GS and even LS cars seem to be very efficient (especially multiple cat systems). Removing the cats will lean the a/f mixture on OBD II cars and probably hurt performance more than help it in a non-forced induction application (and possibly cause detonation).
I've owned two 11 second cars (OBD I) and I retained single cats on both (random technology); there was no measurable difference in 1/4 mile mph with or without the cats. There are well published tests in many performance magazines that show the HP gain from removal of a cat / cats isn't worth the pollution you're introducing into the environment.
The cat systems on the GS and even LS cars seem to be very efficient (especially multiple cat systems). Removing the cats will lean the a/f mixture on OBD II cars and probably hurt performance more than help it in a non-forced induction application (and possibly cause detonation).
I've owned two 11 second cars (OBD I) and I retained single cats on both (random technology); there was no measurable difference in 1/4 mile mph with or without the cats. There are well published tests in many performance magazines that show the HP gain from removal of a cat / cats isn't worth the pollution you're introducing into the environment.
My personal experience is very very similar. I don't have an 11 sec car, but I do have a 12 sec car. I too run RT cat in it. I tried a test pipe (cat off and straight pipe replaces the space) and have tried both variations (test pipe vs RT cat) at both the dyno and the track. The benefits were very very marginal. I'm talking about only a handful of HP at best. I also have a few buddies that tried the same (test pipe vs RT cat vs stock) on similar vehicles, except they were mostly stock. Same results.
Personally, I think it's a complete waste of time to gut, remove, or alter a catalytic converter. If you really really want to have less restriction, buy a race-cat and be done. Personally, I've been there and done that both ways and didn't see any real benefit. Besides, it's terrible for the environment.
You will probably get just as much HP gains from an Octane Booster bottle....
Thread Starter
Pole Position
Joined: Jul 2003
Posts: 370
Likes: 1
From: Pennsylvania
race cats aka test pipes or low cpi cats?
my dad has an audi s4 w/downpipes w/o precats, wow what a diff, but anyways, he is running a pair of cats but they are very very flowing they are 200cpi (cells per inch) i asked a company and he said he can get 200cpi cats but they are from germany and they are 300$ a piece. anywhere u know where i can get true hi flow cats for less? t/y
ryan
my dad has an audi s4 w/downpipes w/o precats, wow what a diff, but anyways, he is running a pair of cats but they are very very flowing they are 200cpi (cells per inch) i asked a company and he said he can get 200cpi cats but they are from germany and they are 300$ a piece. anywhere u know where i can get true hi flow cats for less? t/y
ryan
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
Metal Substrate core cats are the WAY to go. Here is a link I just found that has the best price I have ever seen... only $150 each. This is for earlier cars as Lexus has gone from ceramic core to metal substrate core on later models.
http://www.rpmoutlet.com/powercat.htm
Do NOT just gut a cat. You will LOOSE power. Test pipes are the way to go and they can even loose power on some configurations. Turbo engines are another thing all together but still react very favorably to a high capacity metal substrate cat.
http://www.rpmoutlet.com/powercat.htm
Do NOT just gut a cat. You will LOOSE power. Test pipes are the way to go and they can even loose power on some configurations. Turbo engines are another thing all together but still react very favorably to a high capacity metal substrate cat.
Lead Lap
Joined: Jul 2002
Posts: 524
Likes: 0
From: Novi, MI
Not sure on the LS400 but my GS400 has metal cats on it. Not worth it to remove as they flow very very well. Also, I tried to remove mine and found that the car was unbearably loud with no cats. Holy resonances! It was undrivable! I probably wouldn't bother.
Thread Starter
Pole Position
Joined: Jul 2003
Posts: 370
Likes: 1
From: Pennsylvania
i took my car to the guy that did my catback and he said he could remove the cats then put either 2 or 2.25 press bent pipes to my catback..cost 250$, i asked him why he couldnt just cut off the cats and weld in a 2 inch pipe and he gave me some reason....anyways what do you guys think?
thanks
ryan
thanks
ryan
