I just got done doing a tankful with the auto shut off engaged. In my car it made about 1 MPG more the the shut off engaged. To be fair though, I noticed it wasn't shutting off too often.
Has anyone else tried this?

 

Played with it right after I got the car and then like everyone else disabled it..

The savings heavily depends on your type of driving... If you spend a lot of times at stop lights you get more savings... If mainly dive highway or roads with few lights there is no savings.. It is also tied in with the coast function but I never saw any savings from that...

Also note it only works in normal not sport...

Just using normal vs sport on a PDK was much more dramatic...

 

It's mainly the coasting feature that helps imo. Especially on long motorway journeys I really like the coasting feature.

Btw you can force the coasting feature too...

Make sure the start-stop/coasting button is not enabled of course. And that you are not accelerating.

Then say you are driving in full auto mode, in the lowest gear possible for the speed that your are doing. Usually 7th gear, but sometimes as you go too slow, the lowest gear will be 6 5 or 4 even. When in that gear, pull the + leaver, to go to a lower gear. If you are already in the lowest gear possible, then coasting mode will be forced on. Of course the moment you accelerate again, it will be auto lifted again.

If I'm driving careful with using that, I can get 700km (440 miles) easy out of my tank. ('14 4S)

 

It will shut off more often in the winter when you're not running the A/C. In my Panamera S I saw the MPG improve by 2 when using the auto start/stop in my average commute. That car had the V8.