Silverado guy

Do you have to drive in Eco mode to have it go into 4 Cylinder mode or will it do it all the time while at cruising speeds?
What difference would Eco mode make over other modes?

CorvetteCowboy

In the 2015 corvette A8 the engine is able to switch into either 4 or 8 cylinders at the direction of the computer and the way the driver is driving. The different "modes" change the way the computer thinks. it's simple.

Texan8205

On the M7, yes it must be in Eco mode to cruise on 4 cylinders. Don't know about the A8. Check the owners manual for more specific information on the different modes.

Zymurgy

A6/A8 - V4 mode is active in all modes unless you put transmission in manual mode or if you have a Range AFM Disabler installed or you tune it out
M7 V4 mode is only available in Eco mode

JerryU

Major benefit of an M7, IMO, you have to be in ECO to have it go to 4 cylinder mode. Did that on the Interstate a few times in 2 1/2 years to check mileage difference! With an automatic, to keep it from switching to 4 cylinders in any mode, you have to use the paddles.

I drive in Sport 95% of the time and Weather Mode when appropriate (typically with moderate to heavy rain or when below 40F.)

RedC7AZ

Or the other way to look at it is:
Auto owners have the advantage of having 4 cylinder mode without having to be in ECO mode. All auto owners need to do if for some reason they want to drive without 4 cylinder is to switch to manual shift mode. When you consider the fact manual owners are in manual shift mode 100% of the time, then why would it be a disadvantage for auto owners to have to switch to manual mode for any reason, let alone to avoid 4 cylinders?

Jasonhol

Awwwe..... Did somebody's daddy not teach them how to drive a manual?


I feel the change to 4 cyl. ever so slightly. I'm glad that I control it via eco mode.

Jason

JerryU

As I said it was "My Opinion!" I have tried it on the Interstate and in 7th can definitely feel the transition when I attempt even minor acceleration. The increased mileage is just not worth the use, again IMO. Around town I like the instant response when I'm in the correct gear, which is usually 5th, and I just press throttle.

I also often downshift skipping gears when at cruising speeds. The newly added rev match makes that a perfectly smooth transition. Don't believe I would be as happy with even a dual clutch paddle shifted manual box when going from say 7th to 4th (which I do often coming off an Interstate and making turns in town going from 5th to 3rd.) Having to go thru two other overdrives from an Interstate to get to direct drive for an off-ramp is a waste.

Guess I'm a manual forever guy-until I'm forced to buy a dual clutch manual trans. If GM didn't offer a three peddle box or a dual clutch trans- it would mean buying another brand!

Walt White Coupe

You know the old saying that you can't teach old dogs new tricks, and believe me there are a lot of "old dogs" on this forum but with the automatic transmission the engine switching between V8 and V4 is absolutely seemless. On a recent cruise I was checking how fast you could go in V4 mode and I found that the car would cruise at 80 mph on a level road and stay in V4. The slightest nudge of the throttle and it would switch back to V8. When I checked the "last 50 miles" best MPG, I saw 33.5 mpg. This old dog likes that.

JerryU

Yep, at 73 I'm an old dog but do learn some new tricks all the time! Still working part time and do my own ~100 page website for the business. Do 3 sets of 10 pull-ups on back-day as part of my 7 day a week exercise program! Couldn't do that 30 years ago! In fact usually on my desktop, laptop or where I find time to visit the Forum, on my iPad Pro 12.9 that sits on my treadmill as I'm walking briskly at an incline every day!

But your right, some old things I just won't give up! All my DD's since 1960 have had a standard trans. In fact this is my third 7 speed! The second was the Doug Nash electric operated overdrive 4 speed in my '88 Vette! Even my two compact trucks when between Vettes were 5 speeds. As I said, don't believe I'll be as happy with the dual clutch manual that will have to be paddle shifted as I assume Chevy will be forced to offer as an option to a "slushbox" . Can understand the 8 to 4 cylinder transition is probably less noticeable when going thru a torque converter!

Sure hope Tremic is prepared to supply a dual clutch trans or Chevy buys it from ZF like all the European's-they bought a trans from ZF before!

Tom/99

With 7,400 miles on my 2015 MN7 coupe, it's never been in ECO mode. It's been in sport mode since day one.

RedC7AZ

Just offering up the alternative opinion.

RedC7AZ

I'm sorry, I should have known there'd be a manual owner here that would get defensive and resort to eye roll enducing sarcasm.

joemessman

All I can say is to each their own. I have a A8 now and my wife has seemed to take it over. I love that A8 transmission. I am going to buy a GS for myself in the fall. I am really looking forward to that M7 it is going to be.
All bases will then be covered.

Cur

M7 owner here, and I use it every 2+ hour highway trip to see my parents / in-laws. 34MPG is better than 24MPG e'ery day all day in my book. I guess if I was a millionaire I'd not worry about paltry things as MPG's and the cost of things.

DickieDoo

I find DOD on the M7 to be a bit clunky. It does stay in 4 cylinder mode longer than my other truck does but i'm just not yet sure its worth all the effort to put up with. My mileage does not seem all that great considering all the hype. Car is almost finished being broken in so i will have to wait a bit more before passing final judgment. I'm glad that it will only engage when i force it to ECO mode.
Without it, we can have the lighter Aluminum or CF torque tube, and about 15-20 more hp*. Since GM doesn't EPA certify in Eco mode anyways, i would gladly forgo this "feature" and get the 475hp that this engine CAN produce.

*( LS3 non DOD versus 6.2 LS Truck motor 430hp versuys 403hp due to the cam profile)

JerryU

FWIW, I was in the Interstate today and in 7th gear at 68 mph on cruise control (60 mph limit area) I was getting instantaneous mileage of ~33/34 mpg in V8 mode. This is a flat area in Eastern SC.

I saw a 3 to 4 mph max difference when I tried 4 cylinder mode on this same stretch some time ago. I'll try to compare when I take the Interstate the 16 miles into and back from town using it on one leg.

MAKC7

After attending my Spring Mountain sessions, I always drive my '15 Z51 A8 in the manual mode and paddle shift.

BlueDevilZ51

Maybe he just wanted to have the faster option, that being the auto.