I can only speak from experience with my current car, but 9 times out of 10, I drive around town like an old lady. I actively try to go easy on the gas to save money. But every once in a while I'll get on it hard and fast and really put my foot down. But it isn't often.

I can tell you right now that if I owned a C7, I'd most likely always have it in V4 Eco mode. The only time I'd ever take it out is if A) I was in the mood to punch it, or B) I was at the strip or a meet where I'd want to put the power down.

But on a daily basis, especially as a daily driver, I'd be running in Eco mode. The looks of the car alone are enough to show it off. I don't need to unleashed its power too. At least not under ordinary circumstances.

 

In my first paragraph I was referring to people disabling or driving around the CAGS, not the AFM. Sorry that I wasn't clear on that. My point was that with the CAGS, that is supposed to better gas mileage, it doesn't save any gas if it isn't used. Even though GM put the CAGS on the car to save gas, how many times does the Corvette driver actually shift from first gear to fourth gear. For me, it's NEVER.

While the AFM in the A6 is "on duty" most of the time, it only saves gas when it is in the V4 mode. Out of every 24 hours a C7 is running, how many hours is it running on four cylinders. Even cruising on a typical highway, with each hour of driving, how many minutes is the car actually running on four cylinders? You don't have to drive like Mario Andretti to have the V4 mode drop out and go into V8 mode; just driving in some traffic or on a slightly hilly highway, that loads down the engine will do it.

With the 7M, I bet it is even less than with the A6 as many 7M owners will have the AFM "disengaged".

 

Exactly. And the start-stop system will be used by GM and in Corvettes in the not too distant future. I've read that GM is working on this in order to meet the CAFE requirements of the next few years. I'm not thrilled about my engine shutting off while I am stopped at a traffic light. It will be bad enough in an SUV, but in a Corvette?! I wanted to buy a C7 before Chevy is forced to add that feature to the Corvette. The EPA and CAFE standards have nothing to do with the reality of what consumers want or how the buyer of the vehicle drives the car. Their rules are their rules and all car makers will follow them. I have AFM in my 2012 GMC Yukon and love it on trips; a 5500 lbs. SUV getting 20-21 mpg on a trip in the mountains of Central PA is pretty good. AFM is here to stay. Better get used to it.

 

Based on what I've read, I think you're right that it doesn't take much to make it go back to V8 mode. I still think that V4 will be engaged for the A6 pretty much any time the car is cruising (not accelerating at all) at 30+ mph. For many owners, that's probably greater than 50% of the time that the car is moving.

While I agree that AFM will not be used as much for 7M cars, some owners (including some that have already posted here) will use it. And again, over the lifetime of the car, most of them sold will be automatics.

 

Start stop will raise a huge amount of howls here, just like it did on the BMW, Porsche and Audi sites...but it's good for about 4% savings in gas.....but like every post there....the thread will end with the water on the fire:


You can turn it off anytime forever if you wish.....

 

It's just not me that doesn't want to listen to your one sided view of reality. Take your beloved Acura. Why do they offer the TSX with a 4 cylinder manual(21/29/24) and a 4 cylinder AT(22/31/26) and a 6 cylinder AT(19/28/23) if everyone who walked in was only interested in the maximum gas mileage they can get in a new Acura. Only one of those three gives the maximum gas mileage. Maybe because some people are willing to trade off gas mileage for other things that is the reason Acura offers cars that don't provide the maximum gas mileage possible.

Why would people pay more money for a car that gives less fuel mileage, in your distorted world view? Why do people buy an Acura V6 AT instead of a cheaper Chevy Cruze turbo diesel(46 highway)if they are only interested in buying a car that gets maximum fuel mileage.

I NEVER said that people NEVER take fuel mileage into consideration when buying a vehicle. I said that while most do take it into consideration, other factors are in play, that many times outweigh getting the maximum fuel mileage possible with their money.

 

I'm going to line up with JoesC5 on this. Of all the folks I have known and talked to and interfaced with in the Corvette community, not one has said that they wouldn't by a Corvette if it didn't have AFM.

In other words, the folks who DO care about AFM, on the Corvette, are so in the minority as to be effectively 0.

 

Two things, first is I wish we didn't have to turn it off. My current car has start/stop OFF by default, not on.

Secondly, using some WAG numbers, 4% saving will save about $64 dollars a year, in gals that would be 16.8 Gals. or one fill-up a year. For the average C7 buyer, I would guess that is just not an issue.

 

Most are somewhat concerned about gas mileage, but are not obsessed about extracting hypermileage out of our vettes.That said, there are a ton cheapskates in our ranks who are over the top about EVERYTHING that wrings one more fraction of a cent out of their pockets. Just listen to some of their views. So even though Tadge has to keep all his disparate audience happy, including CAFE standards set by the government, executives needing justified business cases and last but not least the ceaselessly whining and complaining customers, some of which set a new standard of ultra thiftiness on a daily basis. Some of us couldn't less about gas mileage craziness with our vettes, but Tadge has to appease the other crowd that do ( they should all be driving a Prius instead).

 

Exactly, step out of the forum world and into the country club set that buys a huge amount of nice cars and it's important. That simple....again, not defending it, I don't like AFM, but understand why they did it....

 

I agree. I think you represent a good portion of Corvette owners, older and younger included. Sure the car has power and tons of ability, but there's a time and place for everything.

So, when not trying to put the power down, there's nothing wrong with saving some gas money.

 

I agree with you about most Corvette drivers driving their car in a normal fashion, getting what ever fuel economy they get when they get in their car and put it in gear and drive away. I sure don't cruise down the highway at 70 MPH in 3rd gear instead of 6th gear, in order to have maximum acceleration if I decided to punch it every few minutes. And I don't drive it at 30 MPH in 6th gear in town trying to hyper mile it. And, even though I could shift from 1st to 4th at 12 MPH, I don't.

If you could install two hour meters in the C7, one recording the time the ignition is on and the other recording the time the car is actually running on 4 cylinders, I bet the percentage of the time would be very low when running on 4 cylinders vs overall time the ignition is on.

 

Oh yeah, I agree, nobody in a Corvette is going to be trying to beat the Prius club mpg records, that's for sure. But the AFM would be nice for that 1000 mile summer road trip.

 

How do you permanently disable the AFM?

 

yep, like the extra 1 MPG I would get when I'm on the Interstate with that .42:1 7th gear that would be nice in my Z06 when driving at 75 MPH. But there is always a trade off, like always having an eleven extra pounds to move every time I give her the gas when I'm not driving 75 MPH on the Interstate, plus the additional up front cost to add the extra gear ratio.

With the AFM, you are always having to move an additional 25 pounds around, including the time when you are not actually saving gas running on 4 cylinders.

 

Hmmm interesting, I don't think Patman is correct with that statement. At least I haven't seen or heard of any way to do this. If it's an M7 then stay out of Eco mode...an A6 stay in manual shift I guess. That's the only way I know of.....but I could be wrong.

 

My reasoning about the the AFM is that it's clever and potentially worthwhile.
I do not care to make unnecessary purchases. I do not like to shop, I do not like to stop. I do not like to pollute more than the world insists I do. When the world allows me to not spend on consumables, I will buy more durable items.
Like performance or comfort enhancers.

I am not rich, yet I am not thrifty. I just want to make expenditures which are sensible.

Most of my driving is Interstate Highway. If I get ten percent or better mileage at 80MPH with AFM (which seems to be what is in real world results) it would be a good thing. With little obvious performance compromise, I'm in with both feet.

My '08 has the z51 package and it gets about 26-27 MPG because the 6th gear is running 2K on the tach. I would prefer an upper gear that put this at 1500 RPM. I live in Florida and we have few lengthy roads that are not FLAT. While I like going faster than most traffic, it's normally with the cruise on. I do not require instant power for this type of driving. Power band constraints rarely enter into my driving responses, certainly less than drivers in the foothills of the Rockies or the fellow travelers who feel fifth is a true OD. I shift when I feel it's appropriate.

Efficiency is the hall mark of GOOD engineering. Those efficiencies effected may not fit your profile of stated desires. In turn losing 35 lbs will be important to trackers and after the change out of heads/lifters/cams mayhap you'll be able to get the then unneeded weight replaced by lighter, and to you, superior replacements.

You will have the OPTION to make your car faster. You will have a very difficult time making it more of a positive social statement. GM pretty much maxed that out. Environmentally responsible for society and still very responsive to you.

Most likely you will have to reduce your expectations as to how long you can go between partial fill-ups. After all, you wouldn't want to carry that excess gas. (We did this with a very much modded '61. It was a PIA.) You can drop a hundred pounds by running with four gallons instead of a full tank. With the AFM you also will be less likely to run out of gas between those frequent stops.

Just remember you always have the option to make your car less efficient in one parameter as long as you are accepting the compromises in other areas. The envelope can be stretched but it always has the same surface area. What is removed here, ends up there.

 

After seeing some claims in this thread I drove around today displaying the Fuel Economy Info on the DIC screen.
I would guess that in my "around town" driving the car is in V4 mode ~30-40% of the time. After getting up to speed on 25-45 mph roads, it settles into gear and drops the cylinders. I don't drive around like a fool on public roads, that's why there are racetracks, but I don't drive slowly.
S.

 

That's exactly what I mean, the M7 owner could always keep the mode set to sport mode or track mode, and the A6 owner keeps it in manual mode and then AFM never intervenes.

 

I agree. I have an auto and it seems that AFM is in V4 mode most of the time l'm just cruising around and if it helps advoid a gas guzzler tax I'm all for it. I don''t really notice the switch from 8 to 4 or bacK.