AWD Comfort/custom mode vs mpg

[JSolo]

My neighbor with an awd gmc vehicle claims he gets better mpg when the awd is off. That is, only the rear wheels are driving the vehicle. Says the losses are less than with awd on.

I haven't tested this personally, but can't see it making that much of a difference. Might save slightly given fewer driveline losses, but enough to make it a noticeable difference.... I don't think so.

We can't easily disable awd on the stinger (fuse pull perhaps), but it's easy enough to choose custom with the awd setting in its most rwd state.

Thoughts?

 

[Snicklefritz]

The Stinger doesn't disengage anything if you pull the fuse, so the front wheels are spinning the axles and the rest as dead weight. Does the GMC disengage the unwanted axles entirely, so that they just sit there? I could see improved gas mileage if the front wheels are entirely freed from the drivetrain. But not in the Stinger.

 

[Volfy]

In normal everyday driving, an AWD mostly operates in 2WD mode anyway to maximize efficiency, so pulling the fuse or disabling the AWD system by any other means isn't going to do much to improve mpg, to any appreciable degree.

And if you get aggressive enough to activate AWD, or suboptimal road traction trigger AWD, I doubt mpg would be your top priority in either case.

My neighbor with an awd gmc vehicle claims he gets better mpg when the awd is off. That is, only the rear wheels are driving the vehicle. Says the losses are less than with awd on.

Not uncommon for folks to claim something to be true, based simply on their pre-conceived notion(s). Even when they conduct their own impromptu testing, it is far too easy to fall into a confirmation bias trap.

An engineer colleague from way back would claim his pickup truck get better mpg with his tail gate removed... because of less aerodynamic drag. Even tell me his calculates actual mpg at every tankful confirmed it. Then I showed him studies on this very "myth", that used CFD simulation, as well as empirical data from actual road testing to prove having the tail gate in place actually lowers pressure drag. The difference wasn't huge, but the result was very much counter-intuitive to what most folks could visualize.