In a message dated 5/31/99 3:44:40 PM, you wrote:
<<Just had an interesting conversation with a friend, who informed me that a
mechanic recently told him that the octane of your gasoline only matters
if you have a newer engine that can adjust to differing octanes.
How much truth is there in this, and what octanes are people burning in
their ole trucks? (My '54 3100 has the straight six engine in it.)
Tim Lloyd, omaha@tmbg.org>>
This sounds mostly like "new car" theology; it is true that the computer
controlled engines sense knock and adjust the timing accordingly. With
higher octane gas the timing can be advanced more producing more HP.
On the older cars/trucks (the only ones that really count), octane required
is a combination of compression ratio primarily and engine timing/fuel
mixture secondarily. Try proving that high octane gas doesn't matter in an
11:1 compression ratio late 60's muscle car. Running low octane will destroy
them.
On older cars that have alot of carbon built up in the heads, burning higher
octane gas can help reduce pinging a little. . .glowing carbon will still
cause detonation/pinging happen though. So it would be better to rebuild
really. . .
Anyone else?
Mark Noakes
Knoxville, TN
58/56 Suburban
66 Corvair Monza
86 Silverado
86 Corvette Indy convertible
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