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Old 06-22-2008, 08:21 PM   #14
Tru2Chevy
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Quote:
Originally Posted by IROCdan330 View Post
I find, considering i drive 94 miles daily, that gas mileage "tips" are totally dependant on the vehicle.

Shutting off the car at a light I think is silly, the car still has to be in open loop for x amount of time, and open loop = more fuel than when in closed loop like you just were at idle at the light.

Second, I think being "gentle" from a light can be a waste dependant on the car again. If you were to graph it, by being at very light throttle, the engine is under a given load for a longer period of time, instead of just climbing through to get to its high gear. That relates to using more fuel while attempting to get up to speed. This is why, a car with a 3.73 gear will get better city mileage than a car with a 2.73 gear, under the same conditions of course.

Speed on the highway is totally dependant on where the engine is most effecient. Most small engine cars tend to be most efficient around 55 mph. A bigger engine that likes to breathe will be more efficient at speeds above that. My camaro (87) for example, will get 17 mpg at 55-60, 19 at 65-70, and about 22 mpg at 75-80 mph. My hyundai will get 35 mpg at 55-58 mph, but 32 at 65-70. A customer at work was talking about mpg in his E63. City driving the car will get 12-14 mpg, however if he cruises at 85 it will get 25 mpg, lower than that and he gets only about 17-19, which is where they are rated at.

A/C will deplete gas mileage in city/traffic driving. However at highway speeds the load is much less on the engine so mpg doesnt suffer nearly as bad. 1 mpg or less on the highway loss to me is worth it if im comfortable.

I find one of the universal tricks to geting decent mpg is not to necessarily use a light foot, but more so a steady one. Cruise control is your friend. Some cars even have it setup so that when cruise is engaged fuel trims are leaned out substantially.
All very good points, especially the last one.

Other good things to do are to pay attention to what's going on down the road from you, so you can adjust accordingly. Also pay attention to the cycle of traffic lights on your commute. There is a set of lights on my way home from work where if you at the first one when it is red, there is no way to come remotely close to making it through the next light before it turns red. Every night I see the same cars tear away from the first light like crazy, only to slam on their brakes when they get to the next light. I don't bother going over 40 (55 zone), and I arrive at the light just after it goes back to green and roll past every sitting, smiling to myself about all the idiots I'm rolling past.

- Justin
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1999 Camry - Beigemobile DD
2002 Suburban - Wife's DD
2004 Grand Cherokee - Not running / Project / Selling?

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