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Old 11-26-2008, 11:02 AM   #16 (permalink)
dichotomous
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Join Date: Nov 2008
Location: vermont
Posts: 142

CivySi - '03 honda civic SI
90 day: 31.99 mpg (US)
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Quote:
Originally Posted by Christ View Post
Problem with pre-heating the cat - Engines run slightly richer during warm up as a means to heat the cat quickly. A cold cat can handle the excess fuel without gross pollution.

Pre-warmed cat + cold engine == engine still running rich and cat over heating.

At least I think. I have no proof to back this up, other than what I know about excess fuel entering the catalyst, and causing it to heat up substantially.
engines run rich to heat themselves up, not the cat. my motorcycle runs richer and in a higher RPM at warmup so the engine gets up to temp faster, there is no cat on that. heck, there is no cat on my car either, but thats actually supposed to have one.
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