FLS2K

I've been stubborn and never put my M7 Z51 in Eco mode. After all, I didn't buy a 460HP V8 to save gas and diddle around. That and I'm a bit uneasy with half the cylinders getting less/more wear than the others. I'm sure that's naive thinking, but...

That said, after 3.5 months and 4500 miles I decided I should see if Eco mode was functioning properly. I have to say I was pretty impressed with the integration. Aside from a slight jerk when entering v-4 mode the system is seamless. When you need the power she goes back to all cylinders firing nearly instantaneously. Maybe I'll actually use it now.

C7Joy

Yes, it works well. I live in a hilly area and don't get to use it much but I do use it out on the interstates. I had a best run of 30.3 mpg using it. Impressive!

dvilin

Nice to know, so far I am enjoying the 460 hp and not sure if I will ever give the eco mode a try.

Tom/99

I'm at 5,600 miles on my 2015 7 speed, and still haven't had it out of Sport mode. I didn't want a 4 cylinder car.

Weasel

I tried it for the same reasons plus, I was going somewhere and felt bored. Really quiets things down.

Corgidog1

I tried it for the first time on Sunday when I had about 30 miles of highway driving ahead of me. I was just cruising and I was a little low on fuel so I figured let me see how it works. Very seamless and when you give it gas it goes back to V8.

Cobraboy

Why not use it? People seem to think it is going to run like a 4 cyl all the time and cut the HP in half. It is pretty much seamless and when you press the gas a little you are right back into the normal 8 cyl.

Larry/car

I have the same feeling. From what I have seen on other cars, the eco function doesn't same much fuel if any. In and around town the system will not save much, out on a level open road - a mile or two per gallon, maybe.

fredl11

I use it on trips and enjoys the mpg

Ernest_T

If you drive on the highway, and you aren't doing 120 mph, you only need about 100 hp to maintain speed. My car goes in to V4 mode on Hwy 130 which has a 85 mph speed limit. I t will slip into V8 mode on the hills.

Ernest_T

I see a big difference in instantaneous mpg in V4 mode and an average of about 5 mpg over a larger distance. Granted, I live in Texas and I spend a lot of time on the highway, not urban areas. I have averaged over 25 mpg in 3500 miles of ownership which has been the biggest surprise to me.

rcooper

In Austin we are very close to the hill country. This means that there are lots of twisties and up and down grades, not good for any kind of economy. And this is even more true with the way I drive. Never had it in V4 mode and always in sport and sometimes in track. In fact the car has only been in 7th gear once, that was a 150 mile segment of the trip to Blowing Green for the Bash, and that was interstate at 75 mph.

C7cmnthru

I have an A6 so I don't have the benefit of it not kicking in automatically in every mode when in "D". In any case, I have used economy on several longer trips. Its seamless and appears to be worth at least 3 to 4 mpgs.

10mm_

I've never felt any jerk at all when it switches, maybe the transmission shifting but not when it just switches modes.

alienranch

Eco is good for long highway stretches. Then again, the car is probably running in V-4 mode on highway stretches whether in Eco or not (unless in Track)

TEXHAWK0

You are braver than I am..

I got 32.9 MPG in 6th gear on cruise control, and I just cannot make myself go to Eco mode.
On manual cars, Eco mode is locked out in all other modes.

sccaracer46

I usually drive in Sport Mode when driving locally, but when cruising on the interstate, I drop it into Econ Mode and have experienced exceptional 25 & 50 mile averages as high as 46 mpg on flat and level highway with cruise set at 70mph! I have a 2014 Seven speed non-Z51 and have accumulated 28,000 miles with a life-time average of 25.8mpg! This is an incredible car[ATTACH]47891221

Ernest_T

Yes it is. You can go from cruising at 35 mpg to laying down massive amounts of rubber and smoke in an instant.

ratman6161

I've got a 2014 Z51 with M7 and I've done quite a bit of experimenting with ECO mode. I can't speak to the automatics but I think that people who are feeling a "jerk" when it switches from V4 to V8 mode may be using ECO mode in conditions it isn't really intended for.

On my 42 mile drive to work, about 35 miles of it is on country two lane state highway. Its a 55 MPH speed limit with real world speeds (usually traffic limited) anywhere from 50 to 65. This is definitely a poor road for using ECO mode. The speed varies too much because of the mix of fast movers and slow pokes, occasional traffic lights, rolling hills etc. In these conditions I will sometimes really feel it when it switches from V4 to V8 and the improvement in fuel economy seems very small.

Cruising at a steady 70+ on the interstate however, it s completely different story. Out there it's very smooth and I don't get any of the "jerkiness" when it occasionally has to go back to V8 mode for a hill or something. Note: I read an article somewhere quoting a GM engineer as saying that the engine makes about 120 HP maximum in V4 mode and that is plenty for nearly all steady state highway cruising.

My rule of thumb is that if the situation warrants either 6th or 7th gear + cruise control, then ECO mode works well. At slower or more variable speeds, stick to touring. So its not for everyone and its not for all conditions but where it works, it works well. I kind of feel for the automatic transmission crowd that get V4 even in touring mode however. Too bad they didn't make it only in ECO mode like with the M7.

LDYSTIG

I tried eco mode about two months after I got my car, drove it for 30 seconds and decided I didn't like it

Between my highway commute to work (20 miles roundtrip) and my spirited weekend driving, I usually average 20 mpg a tank. No complaints!