1991LS400 Posted November 12, 2004 Share Posted November 12, 2004 How many catalytic converters does my 91 LS 400 have? Only two, right? Does the rear of the vehicle have catalytic converters also? Quote Link to comment Share on other sites More sharing options...
silvermate Posted November 12, 2004 Share Posted November 12, 2004 yes you're right it has 2. followed by some silencers and mufflers Quote Link to comment Share on other sites More sharing options...
1991LS400 Posted November 13, 2004 Author Share Posted November 13, 2004 Thanks. When adding two new catalytic converters what else should I replace and what things should I watch for? Should I get a whole new catback exhaust system, O2 sensors (how many), things of that sort. Any help will be appreciated. P.S. Lextreme and I think cureline both said that the stock catalytic converters and the way it was kinked to fit the catback exhaust system was not good...er...something like that. Do any of you guys have any idea what I'm talking about? What should I do? If I get a brand new exhaust system it should be fine, right? Thanks guys! Quote Link to comment Share on other sites More sharing options...
92Lex Posted November 13, 2004 Share Posted November 13, 2004 If you get a brand new OEM exhaust or if you get an aftermarket exhaust? Quote Link to comment Share on other sites More sharing options...
Travieso~13 Posted November 14, 2004 Share Posted November 14, 2004 The position that the cat's are located restrict exhaust air flow, you want to get them as flat as possible, Quote Link to comment Share on other sites More sharing options...
silvermate Posted November 14, 2004 Share Posted November 14, 2004 Lextreme and I think cureline both said that the stock catalytic converters and the way it was kinked to fit the catback exhaust system was not good...er...something like that. Do any of you guys have any idea what I'm talking about? What should I do? If I get a brand new exhaust system it should be fine, right? well the Ls exhaust sytem is very restrictive, but i mean its a Luxury car, and all those silencers and cats and mufflers ect........are need to keep the 4L v8 quite.. cut all of those out and it will sound like a dadgum nascar (not really) you can get by with removing 1 silencer on each and it will not change the sound of the vehicle. but in all seriousness, it all just depends on what you are trying to do with the car,ie....just upgrade parts, make it a little more free flowing, or make it loud....... like i said above its a LEXUS and its a luxury car, not a hotrod but whatever floats your boat is cool with me. :D Quote Link to comment Share on other sites More sharing options...
1991LS400 Posted November 14, 2004 Author Share Posted November 14, 2004 Lextreme and I think cureline both said that the stock catalytic converters and the way it was kinked to fit the catback exhaust system was not good...er...something like that. Do any of you guys have any idea what I'm talking about? What should I do? If I get a brand new exhaust system it should be fine, right? well the Ls exhaust sytem is very restrictive, but i mean its a Luxury car, and all those silencers and cats and mufflers ect........are need to keep the 4L v8 quite.. cut all of those out and it will sound like a dadgum nascar (not really) you can get by with removing 1 silencer on each and it will not change the sound of the vehicle. but in all seriousness, it all just depends on what you are trying to do with the car,ie....just upgrade parts, make it a little more free flowing, or make it loud....... like i said above its a LEXUS and its a luxury car, not a hotrod but whatever floats your boat is cool with me. :D ← I want it to be more freeflowing because I will be adding SOME performance parts to my Lexi, however, I don't want to sacrifice too much and make my car LOUD. I still want it to be silent, maybe a little "buzzing" from the muffler is ok, but other than that, no extreme loudness. Well, since the LS OEM exhaust system restricts airflow what does that do to the car? If I get an aftermarket exhaust system that is more "straight" how will that help my car, or will it not help it? P.S. All in all, I just want to get my car up to par as much as possible...PERFORMANCE wise...without sacrificing my Lexus that much. Any ideas on what I should do? Quote Link to comment Share on other sites More sharing options...
1991LS400 Posted November 14, 2004 Author Share Posted November 14, 2004 Lextreme and I think cureline both said that the stock catalytic converters and the way it was kinked to fit the catback exhaust system was not good...er...something like that. Do any of you guys have any idea what I'm talking about? What should I do? If I get a brand new exhaust system it should be fine, right? well the Ls exhaust sytem is very restrictive, but i mean its a Luxury car, and all those silencers and cats and mufflers ect........are need to keep the 4L v8 quite.. cut all of those out and it will sound like a dadgum nascar (not really) you can get by with removing 1 silencer on each and it will not change the sound of the vehicle. but in all seriousness, it all just depends on what you are trying to do with the car,ie....just upgrade parts, make it a little more free flowing, or make it loud....... like i said above its a LEXUS and its a luxury car, not a hotrod but whatever floats your boat is cool with me. :D ← I want it to be more freeflowing because I will be adding SOME performance parts to my Lexi, however, I don't want to sacrifice too much and make my car LOUD. I still want it to be silent, maybe a little "buzzing" from the muffler is ok, but other than that, no extreme loudness. Well, since the LS OEM exhaust system restricts airflow what does that do to the car? If I get an aftermarket exhaust system that is more "straight" how will that help my car, or will it not help it? P.S. All in all, I just want to get my car up to par as much as possible...PERFORMANCE wise...without sacrificing my Lexus that much. Any ideas on what I should do? ← Quote Link to comment Share on other sites More sharing options...
92Lex Posted November 14, 2004 Share Posted November 14, 2004 Forced induction. Quote Link to comment Share on other sites More sharing options...
Synthualynn Posted February 17, 2020 Share Posted February 17, 2020 I have a 97 lexus ls 400 I was told it has 4 cats on it is that true and where are they located Quote Link to comment Share on other sites More sharing options...
sha4000 Posted February 18, 2020 Share Posted February 18, 2020 You have 2 cats and a resonator on the mid pipe that does double duty as a resonator/cat. Quote Link to comment Share on other sites More sharing options...
vissine Posted February 20, 2020 Share Posted February 20, 2020 Mine is 96, I can relate to 95 and 97 models. There are 2 resonators near the exhaust outlets. Whoever told you that it has 4 cats doesn't know what they were talking about. Quote Link to comment Share on other sites More sharing options...
duffylouise124 Posted February 28, 2020 Share Posted February 28, 2020 Thanks. When adding two new catalytic converters, what else should I replace and what things should I watch for? Should I get a whole new cat-back exhaust system, O2 sensors (how many), things of that sort? Any help will be appreciated. Quote Link to comment Share on other sites More sharing options...
vissine Posted February 29, 2020 Share Posted February 29, 2020 Just 4 gaskets (2 each) (front and back of the cats). Before removing the bolts, spray the bolts with penetration liquid and leave them alone overnight. There is no reason to replace the O2 sensors. Quote Link to comment Share on other sites More sharing options...
4.0Lover Posted November 30, 2022 Share Posted November 30, 2022 On 2/17/2020 at 11:01 AM, Synthualynn said: I have a 97 lexus ls 400 I was told it has 4 cats on it is that true and where are they located Definitely not true. They only come with 2 followed by silencers and a muffler Quote Link to comment Share on other sites More sharing options...
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