You picked up 3 mpg by switching to 93 octane?.. Better check that calculator, I find that hard to believe. I sure don't wanna start an octane war thread, but if your rig is tuned for 87 octane and is in good working order, it won't run better on 93. Now to add the caveat...unless there is something wrong with your motor, i.e. carbon build up, bad tune, excessive heat, then higher octane might help. Also, if you added a tuner then you may need to run 93 octane.Intersting......I just bought an '04 Sierra EC/SB 8.1/Alli 3.73 (stock)
Pulled an enclosed M/C trailer (12" extra height) to Florida and back.....about 6000# gross tralier weight......3400 mile average was 9.7......I commute 180 miles a day and I have been "playing to see where the mileage would be.....running exact route daily with 87 octane....10.5 to 11.6......using 92/93 octane, it went to 12.7 to 13.1........
I guess stranger things have happened, but it's tough pickin' up that much mileage even when you add mods to it, i.e. some tuners boast mileage increases, and your truck is using a 1 qt of oil every 3000 miles.Well,
I still run the same route every day (have for 9 years) and my mileage last night for the round trip was 13.1........best I got on 87 was 11.1.....so that is 2 mpg, not 3........I have checked to seeif anything had been changed on the truck and to the best of my knowledge no upgrades have been done. BTW, those mileages on on a calculator not the truck computer........(whic is very close)
But then I was told I would never see above 8 pulling my trailer either......
Everything else seems to fall into line on this motor.....1 qt every 3M miles, etc, etc.........
I have the 6.0, but some 8.1 owners say they can pick up 1-1.5 mpg with a good tune on the PCM. Maybe some of them will chime in. Only other thing might be a set of taller tires, but it'll be a minimal mileage increase. 235/85/16's at about 70psi will pickup a tad bit of mileage, but most don't like the small tread width. They are about .3" narrower than the 245's and the same height as a 265/75/16. Make sure all extra weight is out of the rig and a conservative driving style will do more than anything else, mileage-wise.HB,
Well you're probably right.............after the truck settled down I'm getting about the same on the highway with either 87 or 92......13 to 14 and 10 in town. About 9.5 with the M/C trailer.
Happy with the power of the 8.1 but would like to pick up a bit of mileage when not towing......any suggestions outside of headers and pipes (they're on the way).