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-   -   Do manuals coast farther then automatics? (https://ecomodder.com/forum/showthread.php/do-manuals-coast-farther-then-automatics-29166.html)

Baltothewolf 06-07-2014 04:09 AM

Do manuals coast farther then automatics?
 
I have been thinking about this the past few days, and I figure I would just ask. Do manuals coast farther than automatics? Both in neutral. Lets say you drive the automatic and manual on the same exact piece of land, at the same speed put both cars in neutral, which one will coast farther?

gone-ot 06-07-2014 10:36 AM

Which, IN or OUT of gear(s)?

Manuals have LESS overall power loss (~12-15%) AND can be placed in NEUTRAL, but some gears are always engaged.

Automatics have MORE overall power loss (~15-20%) BUT are never completely disengaged due to combination of pump and torque converter operations.

UltArc 06-07-2014 11:29 AM

In theory, the automatic will. Automatics weigh more, and all things being equal, adding weight adds momentum. Imagining like you said, both in neutral at the same speed in the same spot with same conditions, adding weight will increase the coast distance. Granted it's not too much weight, standards have weighed less in every vehicle I have compared the two transmissions.

ecomodded 06-07-2014 12:05 PM

Being about 100lbs heavier then standards hauling that heavy automatic transmission costs you fuel just in its shear weight let alone its friction losses.

Most of the wasted fuel caused by the automatic trans is due to the lack of early/lower rpm high gear engagement, I suspect you could due very well with a gear selectable automatic trans.

UltArc 06-07-2014 12:16 PM

Quote:

Originally Posted by Baltothewolf (Post 428455)
I have been thinking about this the past few days, and I figure I would just ask. Do manuals coast farther than automatics? Both in neutral. Lets say you drive the automatic and manual on the same exact piece of land, at the same speed put both cars in neutral, which one will coast farther?

An automatic will win in this regard- it should coast further, all other things being equal.

ecomodded 06-07-2014 12:19 PM

2 feet further ? 10 feet further ? might friction losses cancel it out ?

UltArc 06-07-2014 12:26 PM

What friction occurs when it's not in gear? I didn't think there was any.

ecomodded 06-07-2014 12:27 PM

input shaft is still spinning

But perhaps that's not a real good argument as the standards transmission is as well , only with lighter fluid viscosity

UltArc 06-07-2014 12:51 PM

I am not aware of the differences between the standard and auto, I was only aware of the weight difference. I couldn't speak to the input shaft, but I imagine if both have then it would be working the same.

California98Civic 06-07-2014 02:25 PM

Where does the auto trans fluid pump get its power? Is it a parasitic load on the trans directly, indirectly via the engine, or more indirectly via some electrical system drawing on the battery?


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