V8=v4 ?
Melting Slicks
Joined: Jan 2017
Posts: 2,706
Likes: 897
From: CONCORD CA.
It may be a gimmick, but it does at least offer some benefit. I see 2 - 4 mpg improvement on long steady freeway runs. Not much I know, but when you are on a long road trip, it adds up. Having said that, I rarely use it, again only on long road trips.
Safety Car
Joined: Sep 2005
Posts: 4,226
Likes: 643
From: Orange County Ca
Even if so, with the drawback of lower reliability, costly complexity, etc., I think the vast majority of informed Corvette owners would not pay $.01 for it as a stand alone option at initial purchase.
Melting Slicks
Joined: Jan 2017
Posts: 2,706
Likes: 897
From: CONCORD CA.
I'm not promoting it one way or another, just letting you know what I have experienced. The range is obviously dependent on mph. I haven't used it more than a few times, just checking to see what the results would be.
Team Owner
Joined: Jul 2004
Posts: 28,475
Likes: 3,291
From: Hartford WI
I wouldn't bother. I got the Diablo which can do the AFM thing but it can change the ECM program some to give it better performance (as said by others), change the transmission shift some and I don't need some throttle fooler to make the ECM give it more throttle since I can change the sensitivity.
Team Owner
Joined: Jul 2004
Posts: 28,475
Likes: 3,291
From: Hartford WI
I've managed to kick it out of the car a couple times. Wasn't going to see if the 3rd time was lucky and the OBD2 port gets damaged. Beyond that, I wasn't interested in having to remove it before emissions testing and make some drives to get it into readiness state for testing.
Tech Contributor
Joined: Oct 1999
Posts: 41,058
Likes: 9,820
From: Charlotte, NC (formerly Endicott, NY)
I have seen some fuel economy improvements using Eco Mode on my Z06 M7. By playing around with ECO I found that AFM works in Gears 4, 5, 6 and 7. In 7th gear it switches back and forth between 8 and 4 and 8 quite quickly. Every little rise or dip in the road causes it to switch. Some of those dips and rises in the road are just the normal lousy construction seen on our interstates where a level road really isn't level.
I found the best gear to use for fuel economy is 6th gear at speeds up to about 75 mph. With 6th gear, there is a little more gearing to support 4-cylinder operation. In 4th gear, AFM works around town from about 25 mph upward and there is enough torque to operate in 4-cylinder mode unless going up a fairly noticeable hill.
There is no noticeable lag when hitting the throttle, as the lifters seem to switch back to 8-cylinder operation as soon as the throttle starts to move.
As for lifter failures due to using AFM, I have no clear idea whether that is an issue or not. There aren't many failures reported in C7s and it isn't clear whether A8 owners were inhibiting AFM through tuning or a Range device or in the case of M7s if they were using Eco Mode or not. So inhibiting AFM may not stop an AFM lifter failure.
Bill
I found the best gear to use for fuel economy is 6th gear at speeds up to about 75 mph. With 6th gear, there is a little more gearing to support 4-cylinder operation. In 4th gear, AFM works around town from about 25 mph upward and there is enough torque to operate in 4-cylinder mode unless going up a fairly noticeable hill.
There is no noticeable lag when hitting the throttle, as the lifters seem to switch back to 8-cylinder operation as soon as the throttle starts to move.
As for lifter failures due to using AFM, I have no clear idea whether that is an issue or not. There aren't many failures reported in C7s and it isn't clear whether A8 owners were inhibiting AFM through tuning or a Range device or in the case of M7s if they were using Eco Mode or not. So inhibiting AFM may not stop an AFM lifter failure.
Bill
Team Owner
Joined: Jul 2004
Posts: 28,475
Likes: 3,291
From: Hartford WI
I have seen some fuel economy improvements using Eco Mode on my Z06 M7. By playing around with ECO I found that AFM works in Gears 4, 5, 6 and 7. In 7th gear it switches back and forth between 8 and 4 and 8 quite quickly. Every little rise or dip in the road causes it to switch. Some of those dips and rises in the road are just the normal lousy construction seen on our interstates where a level road really isn't level.
I found the best gear to use for fuel economy is 6th gear at speeds up to about 75 mph. With 6th gear, there is a little more gearing to support 4-cylinder operation. In 4th gear, AFM works around town from about 25 mph upward and there is enough torque to operate in 4-cylinder mode unless going up a fairly noticeable hill.
There is no noticeable lag when hitting the throttle, as the lifters seem to switch back to 8-cylinder operation as soon as the throttle starts to move.
As for lifter failures due to using AFM, I have no clear idea whether that is an issue or not. There aren't many failures reported in C7s and it isn't clear whether A8 owners were inhibiting AFM through tuning or a Range device or in the case of M7s if they were using Eco Mode or not. So inhibiting AFM may not stop an AFM lifter failure.
Bill
I found the best gear to use for fuel economy is 6th gear at speeds up to about 75 mph. With 6th gear, there is a little more gearing to support 4-cylinder operation. In 4th gear, AFM works around town from about 25 mph upward and there is enough torque to operate in 4-cylinder mode unless going up a fairly noticeable hill.
There is no noticeable lag when hitting the throttle, as the lifters seem to switch back to 8-cylinder operation as soon as the throttle starts to move.
As for lifter failures due to using AFM, I have no clear idea whether that is an issue or not. There aren't many failures reported in C7s and it isn't clear whether A8 owners were inhibiting AFM through tuning or a Range device or in the case of M7s if they were using Eco Mode or not. So inhibiting AFM may not stop an AFM lifter failure.
Bill
I really don't care about the lag. If you are racing seriously, it might be a thing. If you were racing, will AFM even come on? If not, I suspect the difference we feel is more placebo and indignation than effect.
I'm guessing that the issue with the AFM is more of a guess than a real hypothesis.
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