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Old 02-14-2012, 09:52 PM   #137 (permalink)
SentraSE-R
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Join Date: Jun 2009
Location: Bay Area, California
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Mean Green Toaster Machine - '06 Scion xB
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UFO, my perception is I make it worse if I use 40% less gas, but emit 7500% more air pollution. Obviously, that's a very simplified view. I suspect if someone crunched the data, and I could understand it, I'd be driving a diesel, too. I've owned two diesels in the past, an '84 Toyota Tercel, and a VW Rabbit.

Cd, I hope someone who understands cats will chime in. I don't think preheating the cat helps much. The hot exhaust gases light the cat within a few blocks of driving. N.B. it takes a lot longer (5-10 minutes) to light the cat by just idling the engine. When the cat's metal surfaces are hot enough, they catalyze the HCs with O2 into water and carbon dioxide. Preheating the cat to 550F electrically would take a lot of energy, and be extremely wasteful, compared to heating it with 1200F exhaust gases.

I suspect cat/header wraps on the cat are a wash. They might help maintain heat for better catalysis, but they may also damage the cat by overheating it.
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Darrell

Boycotting Exxon since 1989, BP since 2010
Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac? George Carlin
Mean Green Toaster Machine
49.5 mpg avg over 53,000 miles. 176% of '08 EPA
Best flat drive 94.5 mpg for 10.1 mi
Longest tank 1033 km (642 mi) on 10.56 gal = 60.8 mpg

Last edited by SentraSE-R; 02-15-2012 at 08:46 PM.. Reason: Corrected 10X percentage error!
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