<VV> Gazz

[Padgett]

At 02:59 PM 5/9/2006, you wrote:
>     Let's get back to basics.  In my area, Premium  fuel (93-94 RON) costs
>only 20 cents more than Regular gas (87 RON).

Right there says that something is rong. Traditionally, HiTest  has cost 
10% more than regular. When it was 40 cents/gal for reg, premium was 44, 
$1.00/$1.10, $2/$2.20. Suddenly there is not so much of a premium for 
premium. What's going on ?

Second with the price per barrel rising, at what point will synthetic oil 
be less expensive than dino ?

Third, the only real gas saver found by the FEA (predecessor to EPA) was a 
gadget called a "PassMaster" that turned off the a/c compressor when the 
vacuum dropped under about 10 "hg.

Fourth the best advice today is to keep the tires inflated. On a 100 mile 
trip with one of my waterpumpers going up with 25 psi in the fronts I 
averaged 24 mpg. Coming back with 35 psi it averaged 27 mpg according to 
the onboard computer. Mostly 70 mph I-road.

And for the Corvair content, if you can avoid detonation, regular should 
give the same MPG as premium (btu content is the same). After some study it 
looks like I have been confused for years. I always thought that the higher 
the octane, the slower the combustion. Now doing a google search the top 
hits on gasoline "flame speed" and octane, the top hits say that the 
combustion speed is independent of octane. Could someone amplify that for 
me please because if true there is no reason to retard the timing when 
running a lower octane. (my rule of thumb has always been 1 degree per 
octane number so to run 87 in an engine designed for 93 you retard six 
degrees initially. According to what I see on the web, this is not true)

My problem is that since I cannot hear detonation, I have to err on the 
side of caution and run premium but logic says that if you can keep the 
heads (particularly around the exhaust manifolds) cool, with under 9:1 
compression it should not need premium . The part I do not understand is 
why the 1966 95 and the 110 horse/PG seem to have exactly the same timing 
and advance specs. The only difference seems to be that the 95 mechanical 
advance starts at 1700 rpm and the 110 at 800 rpm but both top out at 20 
degrees just later for the 95 (4800 rpm vs 4200 rpm) - slightly stronger 
springs on the 95 maybe ? Will a 95 make power at 4800 rpm ?

Another factor in the debate is that back in the day, there were only two 
grades on gasoline: regular and premium. Consequently if an engine did not 
run properly on "regular" the manual specified "premium". Mid-range did not 
exist. If it had I wonder if the owner's manual would have still specified 
"premium".

So many questions and a lot of guesses but few answers.

Padgett