kuziwk Posted June 10, 2010 Share Posted June 10, 2010 how do you know if your cats are clogged? i brought the car up to 160 kmph after that it was barely climbing so i let go, the car accelerates decent off the line better than my neon, so i dont have much to compare to other than taking it to a dyno shop for a few hundred dollars. How much would High flow cats cost, i believe i would need two? Is there a way to punch out the cats without tripping the o2 sensors? it is too much knowledge that the exhaust has resonators and mufflers therefore a lack of cats will not be very much louder. the only reason i brought the car up to past the speed limit was too test the cats, as a result my seat got very warm and i thought the seat heater was on, however, it was not. I can buy some cats on ebay, but does anyone know how many cats the car has? Quote Link to comment Share on other sites More sharing options...
SRK Posted June 11, 2010 Share Posted June 11, 2010 Leave the cats alone. They are a specific fit on these cars, tight to the engine block. That's why the starter is in the valley. There is nothing wrong with your cats - you'd have an O2 sensor code if there was. These cars were among the first to use pre and post cat sensors, and the post cat ones will trip a code if you mess with the cats, or they fail, which is very rare. Find something else to play with. Lexus was very careful in the design of the exhaust system, which is completely made of stainless steel, and I've never heard of the system wearing out - except for some flange gasket troubles. Quote Link to comment Share on other sites More sharing options...
kuziwk Posted June 11, 2010 Author Share Posted June 11, 2010 Leave the cats alone. They are a specific fit on these cars, tight to the engine block. That's why the starter is in the valley. There is nothing wrong with your cats - you'd have an O2 sensor code if there was. These cars were among the first to use pre and post cat sensors, and the post cat ones will trip a code if you mess with the cats, or they fail, which is very rare. Find something else to play with. Lexus was very careful in the design of the exhaust system, which is completely made of stainless steel, and I've never heard of the system wearing out - except for some flange gasket troubles. yea but after 200 000 miles cats usually clog, so if i punched out the cat filters inside the converter would it trip a code? Quote Link to comment Share on other sites More sharing options...
SRK Posted June 11, 2010 Share Posted June 11, 2010 Who told you that cats "usually clog"? They don't know what they are talking about. Urban myth, and certainly not true of Toyota-Lexus components. As I mentioned, if you mess with the cats you'll destroy their function and the post cat O2 sensor which is there to continuously check cat function, will detect that and trip a code. There is no "filter" inside a cat, rather there is a monolithic catalyst, which looks like a sort of honeycomb, which provides the surface area for the reduction/oxidation reactions. Leave it alone is the best advice. Quote Link to comment Share on other sites More sharing options...
curiousB Posted June 11, 2010 Share Posted June 11, 2010 how do you know if your cats are clogged? i brought the car up to 160 kmph after that it was barely climbing so i let go, the car accelerates decent off the line better than my neon, so i dont have much to compare to other than taking it to a dyno shop for a few hundred dollars. How much would High flow cats cost, i believe i would need two? Is there a way to punch out the cats without tripping the o2 sensors? it is too much knowledge that the exhaust has resonators and mufflers therefore a lack of cats will not be very much louder. the only reason i brought the car up to past the speed limit was too test the cats, as a result my seat got very warm and i thought the seat heater was on, however, it was not. I can buy some cats on ebay, but does anyone know how many cats the car has? The LS400 is hardly a muscle car... Quote Link to comment Share on other sites More sharing options...
intakerGS Posted June 11, 2010 Share Posted June 11, 2010 I agree with SRK, cats don't usually 'clog' after a certain amount of miles. That is, under normal circumstances. Cats rely on receiving a proper mix of exhaust gases at a certain temperature. Some 'kill' their cat by over-using certain fuel additives, or lack of proper maintenance; fouled plugs (unburned fuel), bad exhaust valves etc. Many very short trips can also contribute to not fully warming up engine and cat, leaving some unburned residue. Some warning signs that may point to a clogged cat/exhaust chain are noticeable; a major drop in gas-milage, not getting a proper response when accelerating and more than extreme heat from the cat. Quote Link to comment Share on other sites More sharing options...
kuziwk Posted June 12, 2010 Author Share Posted June 12, 2010 I agree with SRK, cats don't usually 'clog' after a certain amount of miles. That is, under normal circumstances. Cats rely on receiving a proper mix of exhaust gases at a certain temperature. Some 'kill' their cat by over-using certain fuel additives, or lack of proper maintenance; fouled plugs (unburned fuel), bad exhaust valves etc. Many very short trips can also contribute to not fully warming up engine and cat, leaving some unburned residue. Some warning signs that may point to a clogged cat/exhaust chain are noticeable; a major drop in gas-milage, not getting a proper response when accelerating and more than extreme heat from the cat. Yea I guess I can leave it alone, I'm just looking for more acceleration, so why was it climbing so slow after 100 mph? Does anyone know of any easy mods? Quote Link to comment Share on other sites More sharing options...
killerFatty Posted June 14, 2010 Share Posted June 14, 2010 If you want to mess with the exhaust take the back two mufflers off. It will give you a little rumble, but nothing crazy. You can still put them back on if you want. There is no decent way to make a noticeable improvement in acceleration without spending crazy money on a turbo or supercharger. there is one aftermarket intake made for the LS and it's a piece of junk. the only place to get bigger cams is lextreme and they are more overpriced than the STEALership. If there was a decent way to make more power I would already have it done lol. BTW just to second what everyone else said, do NOT mess with the cats. You can get a good full custom exhaust for the same price as messing up one cat. do not touch them! Quote Link to comment Share on other sites More sharing options...
kuziwk Posted June 20, 2010 Author Share Posted June 20, 2010 If you want to mess with the exhaust take the back two mufflers off. It will give you a little rumble, but nothing crazy. You can still put them back on if you want. There is no decent way to make a noticeable improvement in acceleration without spending crazy money on a turbo or supercharger. there is one aftermarket intake made for the LS and it's a piece of junk. the only place to get bigger cams is lextreme and they are more overpriced than the STEALership. If there was a decent way to make more power I would already have it done lol. BTW just to second what everyone else said, do NOT mess with the cats. You can get a good full custom exhaust for the same price as messing up one cat. do not touch them! nah, didnt wanna take the mufflers off, its a lexus...a sleeper. So when you blow past the *BLEEP* can civics its funnier, not a fan of civics and i own a 05 dodge neon, lol. The one thing i did do is rip apart the stock airbox for a little extra thorttle response and higher rpm noise. Quote Link to comment Share on other sites More sharing options...
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