Guest jdllaugh Posted February 21, 2002 Share Posted February 21, 2002 Is it legal to go without a catalytic converter in a 240z when swapping in a late-model engine? I assume the rules vary from state to state. I'm in Oklahoma, which doesn't currently have an inspection system, but I would like to know what the rules are generally. What percentage horsepower gain is likely from running without the cat? Quote Link to comment Share on other sites More sharing options...
johnc Posted February 21, 2002 Share Posted February 21, 2002 I don't know the laws in Oklahoma, but removing the cat does violate Federal law. Luckily there are no Federal officers enforcing that law so its back to each state. If OK has a vehicle inspection program you might get caught in that, depending on how the state determines the emissions requirements for the swap. Regarding the horsepower gain - if its a late model engine (post OBD2) the cats are very efficient and you probably won't see much of a horsepower gain. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted February 21, 2002 Share Posted February 21, 2002 I've done that bit. When I pulled the cat from my Z the only thing I noticed was it being a bit more rasspy. Not real gains, It helped ever so-slightly on the low end, but you can get the same gain with a high flow cat. Also, if you use a hollowed cat and run straight tub through it, they may catch you. One of the things they look at when testing your emiss. system is the cat temp. It is going to be much higher then the exhaust system, well because thats how it works (too long to go into). But you can always say .."hugh, so I need a cat thingy?? Well it didn't come with one " That works sometimes. Quote Link to comment Share on other sites More sharing options...
Guest 400 ci 280z Posted February 22, 2002 Share Posted February 22, 2002 hi i live in yukon and i am putting in 69 pontiac 400. i have been trying to find out the emissions stuff for oklahoma but of couse we dont have a web site for ok. i was also trying to decide about a cat. and was thinking about not running with one because of the lack of inspections now. i have also heard that they may start again but i think it is doubtful. if you find any info please tell me. sorry i was no help. chris Quote Link to comment Share on other sites More sharing options...
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