I wrote:

>I guess, the computer shifts the point of ignition forwards on
>high octane gas and you will take full advantages of the gas firing.
>This is one function of the knock sensor.

That's wrong for Vanagons. I read my manual for the >'85 (German)
Vanagons and they have no knock sensors built in. There is no other
way how the computer could recognise low or high octane gas.

Can someone explain me why the van gets a higher milage with
high octane gas?

Helmut
'80 Camper