I use 87 in mine, before and after the I4 swap.  There are some pros and
cons to 87 over 91 octane.

87 will run perfectly fine in any boxer or even a 10:1cr engine like the
2.0L that I am running unless it is really hot and you are subjecting the
engine to a heavy load like tall hills at high altitude or towing a
trailer.  If the timing is set correctly in the boxer knock will almost
never be a problem.  The knock sensor in the 10:1cr engine that I am using
will ensure no knock as well - crazy people like me run at 12 BTDC (+6hp)
and still don't have a knocking problem!  The only disadvantage to the 87
octane is there is usually no expensive cleaners in it for the valves or
injectors.  This is why VW sells a fuel adative which is essentually
Chevron's Techron.

91+ octane (up to 94 here in Quesnel at Mowhawk - 5% alcohol) has the
adatives that keep and engine clean, but unless you want maximum
performance from an adaptive system like Motronic (no stock Vanagon has
this) you are wasting your money.  Higher octane fuel burns slower so there
is more resistance to pre-detionation AKA knock.  The adatives to make it a
higher octane lower the potential energy of the gasoline - causing you to
need more (expensive) fuel to do the same amount of work.  Also alcohol is
very hard on the O-rings and the other rubber parts in a Volkswagen fuel
injection system as it tends to dry them out quicker.

My solution to this is to go to Costco where they have the 3 pack of STP
injector cleaner and the bonus bottle of Octane Booster.  Every other tank
I dump in a bottle of the injector cleaner and when I am carrying a load or
going into the mountians I use the octane booster.

At 03:47 PM 03/03/2000 EST, John M. Moore wrote:
>Hi fellow listees:
>
>With gasoline prices through the roof, for the USA, what grade gas is
>everyone using?  Is it necessary to use 92 octane at $1.55, or is it ok to
>use 87 octance at $1.35?
>
>John Moore
>Tucson, AZ
>
>

--   David Marshall -                    - Quesnel, BC, Canada   --
--    78 VW Rabbit, 80 VW Caddy, 84 VW Westie, 85 VW Cabriolet   --
--       87 Audi 5000 Quattro, 88 2.0L VW Syncro Double Cab      --
-- David's Volkswagen Home Page        http://www.volkswagen.org --
-- Fast Forward Autobahn Sport Tuning  http://www.fastforward.ca --
-- david@volkswagen.org (pmail) or vanagon@volkswagen.org (list) --