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Old 02-27-2012, 11:02 AM   #11 (permalink)
Diesel_Dave
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Join Date: May 2011
Location: Indiana
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White Whale - '07 Dodge Ram 2500 ST Quad Cab 2wd, short bed
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Quote:
Originally Posted by Ladogaboy View Post
I want to add something to Post #8. What oil pan 4 was saying in regards to diesel turbos "loving their cylinders stuffed with air" would apply to at least some gas turbos. I was doing some more research on my car's tuning, and its AFR range is from 9-11:1 from factory. By eliminating back pressure in the exhaust, the AFR does improve. I'm not sure how much fuel efficiency can by gained by increasing from, say, a 10:1 AFR to a 12:1 AFR, but that seems to be a pretty common shift.
Um, something's wrong with your numbers. If you're running a 9:1 air-fuel ratio you'll be blowing so much smoke that your car will kill mosquitos and various other small animals as you drive down the road. For gasoline, an AFR of at least 14.7:1 is required to have enough oxygen to burn all the fuel.

Most gasoline cars run at almost exactly 14.7:1. The exception is lean-burn engines which go a little higher. Diesels run higher and much more varied AFR's from 16:1 or so all the way up to 50:1 or more in some cases (like idle).

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Diesel Dave

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1 Year Avg (Every Mile Traveled) = 47.8 mpg

BEST TANK: 2,009.6 mi on 35 gal (57.42 mpg): http://ecomodder.com/forum/showthrea...5-a-26259.html


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