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Old 12-26-2011, 05:24 PM   #227 (permalink)
abogart's Avatar
Join Date: Mar 2011
Location: Michigan, USA
Posts: 50

EcoCorsica - '96 Chevrolet Corsica Base
90 day: 32.01 mpg (US)
Thanks: 13
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One thing that I have been wondering about is the effect of factory ignition timing retarding at higher load. I can now accelerate at full load at any engine speed, but ign timing drops from about -32 at cruise to -15 or so at close about 80% load, depending on engine speed. The knock sensor doesn't pick up any knock because I use premium fuel. I understand that it is necessary to retard timing under higher load for proper combustion, and I know that I should be gaining efficiency with the higher compression, but I just wonder if I am losing efficiency due to less spark advance, in which case it would negate the efficiency gained from higher compression.
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