New Chevy 6.0L gasser -- Octane?

intheburbs wrote:

brholt wrote:

Redsky wrote:

Gas engines in trucks are engineered to run on regular gas. Burning a higher octane rated gas accomplishes absolutely nothing with these engines. Using a higher octane rated gas than the manufacturer specifies is about as dumb a thing as anyone can do. It will waste your money and can do nothing for the engine's performance as the higher octane gas does not have a higher btu value.

This doesn't seem to be the case for the Ford 6.2L:

Quote (taken from Ford Truck forums when the 6.2 was introduced in 2010. Mike is a engine engineer

"Originally Posted by Power Kid
Mike, I just read that the 6.2L in the Raptor has 411 hp on 91 and drops slightly to 401 on 87. Is there a drop off on the SD version as well? Or is it 385 straight across?

The Superduty version is SAE rated on 87 octane (R+M/2) so it is directly comparable to the 401 hp for the raptor. You will pick up power on the 6.2L Superduty with 91 (R+M/2).

Mike."

Link

Your conclusion is backwards. The standard engine won't "pick up" horsepower by running 91 octane, the Raptor engine is derated slightly when the computer senses the lower octane.

My Chrysler 300 with the Hemi does the same thing. 89 octane is recommended, but the engine will run slightly derated on 87 octane. The lower octane gas is more likely to detonate in the higher-compression engines, so the computer adjusts the timing, reducing engine power.

Engines designed for 87 octane don't sense the higher octane and increase power. That's what aftermarket PCM tunes are for. I had my 2001 Suburban tuned for 91 octane, and the tuner used more aggressive timing. His tests showed an increase of 15-20 hp on the 5.3L.

Not sure why you are saying it is backward. The Ford engine engineer was specific that the 6.2L in the superduties will change the timing and make more horsepower with the higher octane. There is more discussion in the tread if you want to follow it.