What kills my mileage around here is traffic.  It can take two mpg off easily!  Last trip I did in my high mileage Scion xB I got 33mpg on the outgoing 200 mile trip in light traffic, filled the tank at the destination, and hit about 60 miles of stop and go on the return trip in evening rush hour two days later.  The return mileage was 31 mpg, and the route was basically flat.  

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Don Hanson
Sent: Thursday, March 26, 2015 8:25 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Load vs fuel consumption..

My 84 tin top with a westie interior and an inline ABA Jetta motor driving
though a 5sp manual shifter:   I just recently completed another winter
sojourn to the Southwest US.   On my return trip along the east slope of
the Sierra Nevada range, near San Diego to Near Portland, Or...My normal
fuel economy went down, as I expected, because I was loaded to 4900lbs,
weighed on an ODOT highway scale, with half a tank of gas...I dropped from
average of 24.xx to about 22.xx mpg, driving at my normal cruising speeds
of 55-70mph....
   Just today I found another ODOT scale turned on but unattended and
weighed again, without my tools and camping gear aboard for a 2 month
trip......4100lbs....again with half tank, me and my big dog aboard....I am
back to about 24.5mpg average....So that approximately 800bs of tools and
camping gear uses 2mpg to haul around....The ODOT scales are only accurate
to about 100lbs...so

   For those who might be considering one of these "hybrid" ABA/1.8 liter
motors, like the one that I stuck together in my van,  about 50k miles ago,
the fuel of choice is indeed premium fuel with a decent octane rating....I
was told, by Techtonics Tuning as they helped me with parts and
specifications for exhaust, etc etc....I was told this particular combo of
an 8 valve head on an ABA block results in a pretty high compression ratio
and that I should run premium gas...I did some experiments with premium and
regular....the regular burns less effectively....I think the knock sensor
must be working overtime on regular gas but with premium, all is sweet
inside and I get an estimated 1-2 miles per gallon better gas mileage and
have substantially more torque and high rpm power...