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Larry,

I've seen all over that the VR6 motor using a MOTRONIC Engine Management
System (your powerplant) will run on 87 octane. However, I also know
that the VR6 has a 10:1 compression ratio so MOTRONIC will surely always
retard ignition timing to prevent pinging. Basically it's a compromise
that runs a high compression motor on cheap gas. You never really bring
out the full potential of the engine. If you travel unladen most of the
time, I guess 87 shouldn't be a problem. Of course running retarded
increases engine heat and works up your cooling system but it shouldn't
be a problem if you're in a cold region. (Are you?)

So here's my $0.02 worth.

1. If a motor uses knock sensor (like your), it is most probably high
compression. (NOTE: The older 5 cyl. EV motors had two version. The 93
later ones had knock sensors because they were high compression. The
original motor used when EV first came out was low compression, no knock
sesnors. Since VW "hints" at NOT using 87 octane on the 5-cyl high
compression motors, it does not make sense to me why they suggest it's
use on the VR6 regardless of what kind of engine management system they
put in.)

2. Personally if I had your '99 EV, I'd use 89 or even 91. I'd stay
away from 87 unless it was the "only gas available for the next 100
miles".

3. Note too that the BOSCH W8DTC spark plugs are important. These plugs
have 3 negative electrodes and the engine will only properly work with
them. There was a gas station mechanic that undermined this "hign
fangled 3-electrode plug" only to bring no power, rough idle & misfirng
problems to a 5-cyl. low compression EV that he serviced for a client in
the past on a regular basis. Since the owner was not any knowledgeable,
he eventually resorted to 91 octane just to get some kind of decent
performance. After considerable misery, he just bought a '99 EV. I
ended up buying the 5-cyl and put evenything back to specs. Now it runs
fine on 87 octane, but here I prefer using 89 because the engine runs
cooler and gives a smoother idle. (I'm in So California.)

Regards.

Kit Samson


Lary Saltzman wrote: