Quote:
Originally Posted by euromodder
Coasting in gear is a braking technique.  |
well, i always coast in gear in an automatic, 'cause i don't know how i feel about coasting in neutral, since i've heard it can be bad and i don't know very well how an auto tranny works.
in a stick, i've been coasting in gear for a while because of DCFO, then i joined this forum and saw the thread about point 44 of the hypermiling tips, read that thread, and i might change my driving style now. depending on how soon i need to stop.
Quote:
Originally Posted by euromodder
Not overall though.
If you shove it in neutral rather than keep it in gear, it'll roll (coast) a long, long way, slowing down ever so gently.
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but you do most of your driving while on the pedal, right? at least, that's how you get places. so my thoughts were, it seems like there's more resistance in a stick while just rolling than an auto while just rolling, so that resistance is still there while i'm accelerating, making for lower fuel economy.
Quote:
Originally Posted by Ryland
Read your owners manual on how to operate the automatic transmission, most owners manuals tell you how to down shift an automatic transmission for engine braking and it's something that SHOULD be taught in drivers ed too.
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well i'm not really THAT concerned about it...i don't ever plan on owning an automatic, i was just curious.
and the only reason i would ever want to engine brake in an auto would be for dcfo(because if we dismiss fuel consumption, i'd rather use my brakes to slow down than my engine. brakes are cheaper.) and i still don't know...since it seems most automatics don't usually have engine braking, they shouldn't be able to have dcfo...
as for the guys with electronic throttle control, i couldn't figure out exactly how it works, but my guess is that it isn't actually coasting when you let off the throttle, but continuing to feed gas for a little bit, slowly lessening the acceleration so you don't get that dragging feeling.
Quote:
Originally Posted by mort
This is wrong. The fluid coupling in virtually all automotive torque converters is symmetrical. What makes an automatic transmission coast when the selector is in D is that there is an over-running (one-way) clutch inserted in the drive train. This clutch is not part of the torque converter, it is inside the transmission. In L or 2 or 1 that clutch is disabled. Put the automatic in L and you'll feel the same drag as a manual transmission when you lift off the accelerator.
Most of the rest of the original quote is also incorrect. There is slippage in a torque convertor, and so most have internal lock-up clutches that eliminate that inefficiency.
-mort
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interesting. and good to know. i'll have to try that.