SC300 Cats - Pre & Main?
#1
Pit Crew
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SC300 Cats - Pre & Main?
On my 93 SC300 there are two cats, which the shop manual does not describe as having functions different from one another. I know on other cars, the front cat is a pre-cat (or light-off cat?), which really only functions for seconds or minutes after cold start, until the main cat gets hot enough to work. If you take the pre-cat off, for instance on my RX-7, the car still passes emissions when warm with just the main cat.
Any experience out there with removing the front cat, but still being able to pass emissions? I know it wouldn't pass the visual test, but my inspectors (VA) kinda wink at that as long as the numbers are good.
I ask because I'm wondering about headers, plumbed back into the main cat.
Do I understand correctly that the later 300s have two pre-cats?
Any experience out there with removing the front cat, but still being able to pass emissions? I know it wouldn't pass the visual test, but my inspectors (VA) kinda wink at that as long as the numbers are good.
I ask because I'm wondering about headers, plumbed back into the main cat.
Do I understand correctly that the later 300s have two pre-cats?
#2
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there was an NA supra owner that did a smog test before and after he installed the XERD header. after the install he just barely squeaked by the reading with just a few points margin to failure. That header eliminated the first cat. I guess it all comes down to the health of the 2nd cat and of your motor in general.
#3
Chicago Lexus Club Moderator
Originally posted by rscott
there was an NA supra owner that did a smog test before and after he installed the XERD header. after the install he just barely squeaked by the reading with just a few points margin to failure. That header eliminated the first cat. I guess it all comes down to the health of the 2nd cat and of your motor in general.
there was an NA supra owner that did a smog test before and after he installed the XERD header. after the install he just barely squeaked by the reading with just a few points margin to failure. That header eliminated the first cat. I guess it all comes down to the health of the 2nd cat and of your motor in general.
Around here when it's time for emission testing people generally replace the test pipe with a cat and drive around for atleast 20 minutes so the cat is warmed up.
Chris
Last edited by DIrEctQL; 09-26-04 at 10:54 AM.
#4
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actually i didnt take the state into consideration. I think he was in new jersey. I have no idea how strict their laws are. When i had the XERD header in and EGR blocked off i had a friend check my emissions. It was enough to label my car a gross polluter
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