93 octane to 91 octane

[pat0017]

when i change from 93 octane tune to 91 octane tune the ram 5.7l hemi year 2014 uses a gallon more then the 93 octane tune.whats the reason of it.?

[mikel]

fueling is the same from tune to tune...

[DiabloMatt]

probably the lower spark timing is making the engine less efficient and uses more fuel.

[pat0017]

probably the lower spark timing is making the engine less efficient and uses more fuel.

but when i put the 91 octane tune in the car performs better then the 93 octane tune.ps.have try several brands of the 93 octane fuel.still the same.

[mikel]

that indicates your car does not like the added timing of the 93 tune, usually from oiling contamination or poor fuel quality.

Thanks

[DiabloMatt]

my apologies. i misunderstood. i thought it was the other way around. mike is right. it just doesnt like the added octane. some vehicle do that from time to time.