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Old 09-21-2009, 07:55 PM   #19 (permalink)
Master EcoModder
Join Date: Nov 2008
Location: Madison AL
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The Geo - '93 Geo Metro
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Originally Posted by 99LeCouch View Post
^ That's another reason my car runs like poo on E10. The 3800 is designed for straight 87 octane, not 84 octane blended with ethanol to make 87 octane. My car is pre-ignition prone on low-quality 87 octane, so it pulls lots of timing to combat the pre-ignition. Every degree of timing it pulls is ~5 hp lost, so 8-10 degrees of timing pulled is 40-50 hp lost just above idle, when it pings the worst, and isn't making much power to begin with. So the computer dumps more fuel to compensate for the ping, and voila, worse fuel economy.
Do you have the same engine my dad does?
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