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Old 03-18-2011, 09:16 PM   #15 (permalink)
ShadeTreeMech
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Join Date: Apr 2009
Location: Arkansas
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The Van - '97 Mercury Villager gs
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Quote:
Originally Posted by ConnClark View Post
Once again I fail to see how it saves fuel.

lets say I'm driving and its time to up shift from second to third. I start out with the engine at a high rpm. After I shift, my engine is at a lower rpm.
With a modern engine, while the engine is coasting down, you would use no fuel since DFCO would likely cut off the fuel
Quote:
Shifting with the clutch I take some of the high rpm rotational energy and, even though the clutch slips some, use it to generate torque to move the car forward. The rest of the energy gets turned to heat.

Shifting with out the clutch I pop it out of gear at a high rpm and let the engine spin down (wasting energy that could be used) until the syncros line up and pop it into the next gear.
The fact that a modern engine uses no fuel when coasting negates your argument. But regardless, the amount of fuel saved for that simple method of changing gears would be crazy small compared to the driving style shifting without the cltuch encourages compared to the driving style of the clutch fiend.
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Quote:
Originally Posted by jamesqf View Post
I think you missed the point I was trying to make, which is that it's not rational to do either speed or fuel economy mods for economic reasons. You do it as a form of recreation, for the fun and for the challenge.
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