Hi Jeff

Efficient, is a bit subjective... (fuel vs. time)
I also depends on motor and transmission, weight etc.

My 84 Manual Westy gets 21 MPG highway, we two on board and no exterior
accessories and a weekend worth of water / gear.  When I travel around 60
MPH I get 21 MPG, it drops to 17 MPG at 70 MPH.  Note, I have a well tuned
2.1L from a 91 Westy.

The aerodynamics of a piece of plywood doesn't help.
See this link.
http://www.arcindy.com/effect-of-aerodynamic-drag-on-fuel-economy.html

So, when the weather is nice, and I want to get to my destination a bit
sooner, the value of time savings outweighs that of fuel economy.

On average, I travel at 70 to 75 mph, even with AC on.
When I had my 1.9L, my average speed was 65 to 70 mph @ 19 MPG.

Jack R.

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Jeff Palmer
Sent: Sunday, May 19, 2019 10:36 AM
To: vanagon@GERRY.VANAGON.COM
Subject: So what's the most efficient speed to cruise at?

2.1 auto. Curious!
Jeff

Sent from my iPhone