Do all knock sensors adjust the timing through a range of degrees above
and below the adjusted distributor setting?  Do you know what the range
is?  How much xylene or toluene would one add to a gallon of 87 octane
to change it to 92 octane?  I've been adding fuel conditioner at each
fillup for my diesel Caddy, so this would not be an inconvenience at
each fill of my Vanagon.  I'll have to check on the cost of xylene and
toluene to see if there is money to be saved here.  Thanks for the very
informative post, David.

-Dana-

David Marshall wrote:
...
> all done using a 1982 Rabbit Distributor with vacuum advance and vacuum
> retard - generally considered the best performance non-knock sensor
> distributor.  If there was a knock sensing ignition present, there would
> have been no knock as it would have retarded the timing until it
> disappeared - thus giving you less power.  With 87 octane fuel in a high
...