Octane

[Markus]

I have always used 93 octane in the States and 91 in Canada because I get more miles/gallon with the premium fuel.
My work truck is a 2004 Chevy Express 3500 gas engine (6.0L 300hp ). We fueled it up with regular and it ran a distance of 372 miles/tankfull. With premium fuel it runs 435 miles/tankfull......and yes we hauled the same weight.

You used the same weight - that's a good start for the test.

Was your "scientific" test performed on exactly the same route, at exactly the same speeds, and in exactly the same environmental conditions (air temp, humidity, wind speed and direction)? Without this additional data, the inference that you burned less fuel because it was higher octane is meaningless. We need facts, man!

 

[billyshoe]

The electronics that control the engine were designed to be flexable-BUT-they were designed to run on(higher)91-2-3 octane. You will get the most/best performance from the higher octane for one reason, the higher octane permits a slower more efficient burn and the timing will reach a higher degree of advance before it needs to retard it self. This is limited to pump fuel and raising the octane to higer levels than 93 will not improve timing peramiters any ferther with out other electronic engine control modifications. The difference between using 87 octane verses 92-93 octane ais very marginal but should be noticable from a horsepower/mileage standpoint.