The owner's manual for my '91 VW Vanagon GL Campmobile states that one should not use gasoline with an antiknock index below 87, or 91 RON.  Regular gasoline at low altitudes in the U.S. meets this criterion.  It also states that one could use a higher octane rated gasoline for extended high performance driving.  I'm not sure what that means.

Most manufacturers now state that so long as the engine does not knock, the gasoline being used is fine.

---- Jeff Lincoln <magikvw@GMAIL.COM> wrote:
> Regular.
>
> I actually read somewhere (sorry I can't remember the source) that the lower
> octane fuel is actually better for our stock WBX engines because that is
> exactly what they were designed for.
>
> I don't know how true that is but my conscience and wallet sure appreciated
> that little tid bit. It also made a lot of sense the way it was explained.
>
>
> --
> Thanks,
>
> Jeff
> '85 GL (Gertie)
> '90 Carat (Grover - the noble parts donor)
> '86 (We call this one Scrap)
> '78 Bus (Melissa) Patty's Bus

--
David McNeely