I've used Eco mode in 2 different tests, where I was making long out and back runs on Interstate roads. In both cases the maximum mileage difference I saw was less than 1 mpg (0.75 on one and 0.9 on the other).

For those of you that are seeing mileage differences greater than that, were you measuring it at the pump or via the computer? I've found that the mileage computer is consistently 1-2.5 mpg higher than what I calculate at the pump.

HTH, and have a good one,
Mike

 

I use Eco mode often. No issues.

 

I used the instantaneous mpg readout as I was traveling over the same section of highway at the same speed. The difference was between two different sets of readings from the display. If it was a long term test the same could be said for using the difference between the average read outs.

Comparing the average read out to filling the tank and calculating the mpg is sort of fraught with error. The first error is you don't know exactly how full you can get the tank and the second error is differences in actually filling the tank from one time to another because of pump variations even if you use the same pump. If the filter starts to slow the delivery of fuel you can actually squeeze more fuel in the tank Vs having a fast delivery. For the fuel and calculate method you usually have to perform 5 or so total fill ups with over 15 gallons of gas to average out the filling errors. If you average over the number of miles that 100 gallons of gas will take you the accuracy is much better since the filling errors average out.

Bill

 

I use Eco Mode all the time....LOVE IT! I don't understand the big debate here. On road trips, I consistently get 30 to 32 miles per gallon.

When you don't need V8 performance and you want optimum gas mileage, use the Eco Mode!

 

Actually you can get V8 wide open performance in Eco so you can just leave it in Eco while on the streets/highway. Then go to track mode for the track.

Bill

 

I've used ECO mode a few times on extended highway drives. I don't really like what it does to the exhaust note mainly. I generally don't drive more than an hour anywhere in a car though...that's what airplanes are for.

Back when avgas was $7.00/gallon I used "eco mode" more often in the airplane, but now that fuel is $3.50-$4.50/gallon, I usually use go fast mode...though the amount of time it saves is just stupid compared to the extra cost.

I do enjoy having the flexibility to operate however I like. The ability to net 30-32 m.p.g. in a car that can also do 0-60 in 3.8 seconds is just amazing when one thinks back to what we had in the 1970's and 1980's.

 

I was fine with mine (A8, so in all modes) until I went to a Corsa midpipe, at which point the sound of V4 more became much more noticeable and annoying.

I initially turned my AFM off entirely (in the tune) but then revisited it and changed it so that it is on, but doesn't kick in until 54 mph. That way I don't get it on every darned coast-down, but I still have the feature for highway cruise if I want it.

 

Correct me if I'm wrong, and I may very well be, but isn't ECO supposed to change shifts to get into higher gears faster and to switch to V4 mode as much as possible? Therefore, would ECO not have more value in city driving vs. highway?

 

We are in the minority, I'm sure, but I must also give a thumb's up for V4 mode and use it whenever possible. My 2015 A8 realized 8-10% better mileage in V4 mode and my current 2017 M7 is about the same. The A8 would transition with little or no notice, but although the M7 is not as seamless it doesn't bother me at all. I don't understand why people want to decrease their mileage when it doesn't affect performance in any way.

 

Well, you hope it doesn't affect anything. But not everyone is reporting such a dramatic savings in gas mileage. VetteDrMr is reporting less than a 1 MPG difference. And there's the question of uneven wear. Also, excessive vibration and the TC issue, which Tadge has mentioned. These sorts of issues may not manifest early. If I wanted great gas mileage, I'd buy a Prius, and if I wanted great gas mileage and performance, I'd buy a Tesla Model S.

 

This thread was started discussing the 7-speed manual cars, so not for them.

 

If they want to use ECO for EPA certs they have to make it on all of the time or by default. It is primarily for advertising and to demonstrate the quality of GM engineering.

You have to admit that the C7 has amazing fuel economy for the level of performance it provides and that takes high quality, detail oriented engineering.

Way to go Tadge!

 

I have a 2016 Z06 A8 drove 2000 miles round trip 28mpg using eco mode cruise set to as high as 80mph thru mountains of Virginia and Pennsylvania. No problems just kick down to pass all those lovely trucks.
z51vett
Doug

 

And that is one of the great things about the C7. I really don't get the shuttering with the move in and out of AFM. I certainly hear it in the exhaust note though. I only use ECO on long highway trips; ditto for 7th gear. My reward is my record of 32.7 on the highway with the top up. Amazing how with the top down mileage drops significantly. Not that I care when I want to open the top. And I don't care about the mileage when driving for fun...15 is about it. But if I can save on a long ride, why not? The flexibility of this car is phenomenal.

 

I see the skip shift message on the driver's info screen in the center of the dash, but I don't feel anything in the stick shift linkage that forces me into 4th ... I see the message but I can just shift into 2nd no problem ... haven't yet experienced the 2nd gear lockout ... I'm not complaining but anyone else experiencing this?

 

^^^
If you bought your car used it could have a CAGS Eliminator! Only cost ~$20 and an easy install! If it is my 2014 C7 Z51 I sold a few months ago then that is the answer!

It's not needed in a C7 unless you shift out of 1st gear below 17 mph (as I did when in bumper to bumper traffic for the first time and fumbled trying to figure what happened!)

When I changed the brake pads on my new Grand Sport, with the rear jacked up the install was easy. In fact in a TV episode of "All Girls Garage," one of the young ladies installed one on a Camaro in a few minutes while we watched! When she had the car on a lift changing an exhaust part, her co-host was getting a part. So she said, "I'll just take a few minutes to install this skip shift defeat device!"

It fools the computer to thinking it activated the shift blocking solenoid by using a resistor in the connector. Therefore the skip shift light still comes on but it does not activate!

PS: The device is NOT Stupid! GM installs it to help with the EPA required gas mileage test that enables them to show a small increase in mpg! Helps their corporate mpg average! For $20 and an install that takes minutes when the car is jacked-up, for those that don't like it, consider who is being called stupid! It's not as intrusive as my C6 and some prior Vettes and some don't think it's necessary. Some of use do!

Some of those with M7's that use ECO may not want add a CAGS Eliminator and follow the Owner's Manual (page 194, 2017 manual) for best fuel economy and shift out of 1st below 17 mph, 4th to 5th at 25 mph (since you can't use 2nd and 3rd if you shift below 17 mph out of 1st); 5th to 6th at 40 mph and 6th to 7th at 45 mph! Hmm, if you shift at those recommended speeds wonder why you bought a Vette?!

 

When I had a C6 the skip shift was very intrusive and I installed a skip shift eliminator. I am on my second C7 now and I find the skip shift to be virtually a none event, at first I was not even sure the system worked.

 

1 1/2 years I have yet to use it... I agree that it's gimmicky.

 

I have '15 coupe, used eco once, wife said "What are you doing with the gas pedal, the car is jerking" haven't used it since. P.S. to keep peace I did not answer the question!

 

Try using the paddles all the time for a few weeks. You will adjust to it, and shifting will be second nature, just like with a standard shift. I do have a few less gears to shift (A6) but this is what i do, and i find i like my decisions about when to shift better than the computer. When i take a road trip i will use automatic shifting, but as others have noted, the improvement in mileage is minimal, i do it so i won't forget to go into 6th gear. Try it, you'll like it.