Active fuel management mods?

[totheyard]

Why are you guys putting 89 and 91 octane in the Denali? Mine is written that 87 is fine. Or does your new tune call for higher octane? So it sounds like the AFM does nothing for saving fuel. Just a marketing tool to sell some trucks?

 

[soulsea]

You can get a tune specific to which octane rating you wish to use.

The AFM does save fuel on long highway runs.

 

[wcsmith21]

Just what serge said. Your tune changes the octane to your preference.

 

[totheyard]

Copy. I assume that the higher the octane you choose, the bigger the gain.

 

[soulsea]

93 octane tunes are usually there to get the maximum (fuel related) performance out of these engines, not fuel efficiency ... but one doesn't really get a tune just to use 93 octane, it's simply one part of a tune customized to meet one's overall needs.

Norman, honestly the best way to do this is simply to get yourself set up for a BB tune, and tell Justin exactly what you want in general terms. For example you can say I want to make my vehicle as fuel efficient as possible whilst using the lowest octane fuel ... they will tailor your overall tune to that end, including shift points/octane rating/etc.

 

[felixgun]

Why are you guys putting 89 and 91 octane in the Denali? Mine is written that 87 is fine. Or does your new tune call for higher octane? So it sounds like the AFM does nothing for saving fuel. Just a marketing tool to sell some trucks?

You can get the 87 octane "fuel economy" tune or the higher 93 octane tune which will add more HP and give more of a performance boost.

 

[TowGMC]

Even before my BB tune, there was a very noticable difference between running regular and 93 octane. When running regular, throttle response on the highway was definitely poorer. And on two long trips when I ran 89, fuel economy was off 1-1.5 mpg.

Hey, at least I get 93 octane here in Illinois, sorry CA folks.

 

[totheyard]

I know! Max here is 91. Junk state!