Octane

[Larry C Leung]

Probably the BEST indicator if you have adequate octane would be your
fuel
milage IF and ONLY IF you have a consistant trip, day after day after
day. 
Measure your fuel milage (milage on the odometer vs gallons fill, to be
REALLY
consistent, use the same pump and stop filling when the handle clicks the
1st time) 
over a couple of weeks with R+M/2 93 octane fuel. Then do the same with
your
"90" octane mix. If the milage is essentially unaltered, then the "90"
octane would
be perfectly adequate. I did find, with my HT engined (10:1 compression,
single
knock sensor, 1.8 liter 4, similar to the 4000S engine) A2 GTi that there
was a 
slight but perceptible drop in fuel milage with "90" octane vs. 93, but
my trips 
were not consistent enough to be TOTALLY certain. I did NOT note a
noticable
decrease in performance, other than more audible knock on throttle tip in
(my 
timing for Solo 2 was set rather agressively). As I didn't mix until
after the Solo2
season ended, I didn't bother to measure any performance losses, if it
felt okay
seat of the pants, and it saved money at a previous time of nearly
$2.00/gal Premium
fuel, it worked for me.

LL - NY


On Wed, 7 Apr 2004 18:14:20 -0700 (PDT) William Magliocco
<magliocc at rocketmail.com> writes:
> Thank you all for your $0.02.  I did a mix today for
> about 90 Octane & drove about 250 miles on I-20.  Ran
> OK, maybe a little doggier than usual.
> 
> However, the suggestion about putting a gallon or two
> of toluene in the tank (like Eric Kissell suggested)
> sounds like fun!  Would there be a big benefit in a NA
> 6 cyl 10:1 compression motor like mine?  Worth a shot,
> IMHO.
> 
> Also, I agree with the $0.02 about ethanol.  Having
> lived smack dab in the middle of the corn belt, it was
> in the gas whether you liked it or not.  I recall my
> '85 1.8 NA VW GTI had some problems with it.  Vapor
> lock and it seemed to eat a rubber O ring in the fuel
> pump every year or two.
> 
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