Octane and Towing

[PxTx]

I respectfully disagree on it being a waste of money.

My wife has a 2011 Denali with the 6.2. It really is a great set-up. I can only imagine it is even better in 2016. I thought here owners manual said to run premium fuel. Maybe she is waster her money since I did not confirm what the manual says about fuel, but I can't say we're experience any of the negatives listed above.

This could get into a log debate, but on the dyno you can absolutely push the limits of timing with higher octane. If you actually look at the timing maps programmed into the PCM, they vary for tow mode and regular, and have a range of retard once the knock threshold is crossed. Better fuel will let you stay in the more powerful part of the timing map when pushing the engine.

Granted, light load, modest throttle and the higher octane will not be nessisary on many engines. My experience towing with the Chevy V8 is the better octane is worth it.

[Big Block Bill]

I do not know what GMC recommends for grade of fuel in a 2011 Denali, but my 2015 Denali XL must run on Premium according to GMC. I agree on a Dyno when the timing can be adjusted, it will increase performance, but in a stock programmed ECM in a late model vehicle timing is set by the factory programming and increasing octane will not help performance, only hurt the drive ability. FWIW, That's my opinion / experience. I make more money on Premium than I do on regular so I hope everyone buys Premium. Not trying to be a know it all here, but in my world it's just a waste of money unless required by the manufacture. Once again, ENJOY the new ride.

Bill