djnice

The problem I find with the GS/Z51 is the lower rear end gear ratio and wider tires than base stingray. It won't get as good mpg.

roadrnnr

Wouldn't shutting down half the cylinders for a prolonged period of time cause uneven temperatures and wear?

Mike Green9

I'm an LS3 A6 C6 owner looking at the C7's.

I am not opposed to the concept of AFM. But I do worry a bit about the many articles on the problems of frequent Cylinder De-Activation. Google search it.

I can see using it on the highways in the overdrive gears, but I would prefer to have it de-activated when driving around town.


And as a clarification, here is an excerpt from the 2017 C7 Owner's Manual Under AFM:

This system allows the engine to
operate on either all or half of its
cylinders, depending on the driving
conditions. With a manual
transmission, the system is only
active in Eco mode. With an
automatic transmission, the system
is available in all modes, but is more
aggressive in Eco mode.

When less power is required, such
as cruising at a constant vehicle
speed, the system will operate in
the half cylinder mode, allowing the
vehicle to achieve better fuel
economy. When greater power
demands are required, such as
accelerating from a stop, passing,
or merging onto a freeway, the
system will maintain full-cylinder
operation.


M....

Red Mist Rulz

The engine will switch back to V8 mode at least 1 minute every 10 minutes. In many situations, it switches more often : if you encounter a hill, give it more throttle, etc. Auto trans Corvettes switch in and out of V4 mode all the time, even when not in eco mode, and wear doesn't seem to be an issue.

Mike Green9

Is the AFM system in Active Mode when Automatics are in Paddle Mode?

M....

djnice

AFM is off in Paddle Mode.

Yes, the auto trans goes in and out of V4 all the time. I am pretty sure this is what's causing the torque converter problems. I added the Range device for normal driving to prevent V4 and excess TCC wear.

hansesm

It's on unless you are in manual mode. Paddle shifting prevents the V4 mode

Mike Green9

I found this on Page 205 in the 2017 C7 Owner's Manual:
Active Fuel Management (engine
cylinder shuts off)
4-Cylinder Mode
. Normal with automatic
transmission: The engine uses
8-cylinder mode when
accelerating, but changes to
4-cylinder mode when coasting.
. With manual transmission:
Active Fuel Management only
active in Eco mode.
. Off in Manual mode with
automatic transmission unless in
Eco mode.
. Eco keeps the engine in
4-cylinder mode unless heavy
acceleration is needed.


So I would assume that always driving in Manual Mode would de-activate AFM at all times.
If you want AFM, say when cruising on the highway, shift into DRIVE, or turn Eco Mode ON. To turn AFM OFF, shift into MANUAL (with Eco Mode OFF).

If true, you could avoid using AFM around town, and use it on the highway where it makes more sense. Does this make sense?

Thanks,



M...

owc6

Other than the few times I've experimented with D and the AFM, I drive around everywhere in M. Probably only about 5,000 or less in D, with no appreciable difference in fuel economy, BTW.

My AFM is never active in M. This is on a 2014 Apparently, they activated it in Eco mode in M on later years. I've spent some time in M in Eco (only to check if true), and never once has it gone to V4.

FWIW, mine translate seamlessly between V8 and V4.

djnice

Yes, if you keep it in manual you can avoid AFM. With the 8 speed the gears are pretty close together so in M you spend a lot of time pushing the paddles. So sometimes I like having the Range installed and just using D with no AFM. Yes, the AFM is seamless, but I believe it is bad for longevity of the TC clutch.

AdventurePoser

Where I live, lots of curves and mountains, but no place to really open up. No real difference between S and E here. When I go over the mountains and down to the interstate, E is nice and the mileage is amazing for such a powerful car. Me likey.

pdiddy972

Same here - that's what 7th gear is for!