Mechanics

GAS MILEAGE

2001 Nissan Maxima

Will regular gas lessen the gas mileage of a car that requires mid-grade or higher?
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Phurt
July 28, 2011.




Possibly. Higher octane fuel does not produce more power or fuel mileage. It allows engines to be TUNED for more power. That usually means a higher compression ratio which can result in spark knock. Higher octane fuel is harder to ignite so spark knock is reduced. A lower octane fuel might cause spark knock which will be detected by a knock sensor, (if your engine uses one). The Engine Computer will respond by retarding ignition timing which reduces power and fuel mileage.

Using a higher octane fuel in an engine that is designed for 87 octane will not gain anything by way of power or fuel mileage.

Caradiodoc
Jul 28, 2011.


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