Wind resistance is such a large force to overcome you still use power to get
down most descents. I really see this effect with the motor home. It take
really step hills to require any braking and since it is a Diesel, no
throttle if you need any engine braking you need to activate the exhaust
brake. This makes it real obvious.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
David Beierl
Sent: Sunday, March 29, 2015 12:00 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Load vs fuel consumption..

At 12:13 PM 3/28/2015, Dennis Haynes wrote:
>the limit of both efficiency and the edge of destruction. Over the
>years I find it common to get differing fuel economy on trips based on
>direction, especially when mountain ranges are involved. Outside temps
>can also mean a difference.

Every foot of net altitude gain at the end of a trip is you having
dead-lifted the van that high.  On the return you turn that potential energy
back into kinetic, minus the usual efficiency tax.  Hills on the way with no
net gain or loss cost you only the efficiency tax, unless of course you have
to hang on the motor or use your brakes, in which case you lose some as
direct conversion to low-grade heat.

Yrs,
d