^^^
Yep, has nothing to do with China, India etc still building coal fired power plants, or that Natural Gas Produces 1/2 the CO2 emissions/BTU. Why we're <19% Coal for electric power switching to gas turbine generation etc and declining quickly. The folks in charge don't care! Sports car folks will suffer along with all others! Just the way it is. Been around long enough to see most folks don't understand or what to understand technology. Heck we're dropping Math from required learning!

Just easier to convince enough folks zero fossil fuel is the only answer! Too many dull bulbs voting! We'll see.

 

Attached is the schematic for deactivating the lifters. The deactivated condition is when the ECM grounds the wire coming from each of the lifter solenoids. So, not grounded means its will not deactivate the cylinder valves. If you could figure out where those wires are, I think they could be cut. Dont know if it would detect that or not. When it attempts to activate it, it might notice the lack of a load or current, and set a flag. Plus, thats not the only problem. Separate from that, it also shuts injoff the fuel injectors. I don't think a simple disconnect of something will prevent it from disabling the injectors. And, we also know from other sources there is some microslip in the clutch during V4 or transition to V4 (I'm never sure which). And there is the control path to the AFM exhaust flow valves. All together, its probably got to be a software trigger way upstream of all that to prevent it.

 

The only Corvette I would never buy is an E-Ray… adding an entire secondary power train, that requires a battery (a chemical soup) another motor, electronic control systems, and thousands of lines of software just to take a few tenths off the 0-60 time and some fractional improvement in mpg seems like a poor use of resources to me.

Same with auto shut off… adding hundreds if not thousands of engine shut down, engine restart cycles is additional wear and reduced engine life again for a fractional change in mpg…. Before these systems came along we were told 70-80% of engine wear occurs during the start cycle….

AFM is the same… more weight, more manufacturing cost and complexity, more opportunity for failure for fractional improvements…. More complexity most buyer would rather avoid.

The E-Ray is a choice…. But auto shut off and AFM are not…. Thank god my car doesn’t have auto shut off…. Maddening feature I have to turn off every time I drive my wife’s car.

These “systems” add weight, cost, complexity, and potential for increased repair costs …

You could get the same mpg “improvements” by stripping 500-800 pounds out of the car.

Internal combustion engines may have a relatively low “efficiency” but a gallon of gasoline still has 100 times more energy than the same volume of a fully charged battery… that’s not 100 percent more… it’s a 100 times more energy… if internal combustion is that inefficient and EVs are 85% efficient it seems that best opportunity to improve is in the internal combustion space.

And these systems are meaningless compared to what goes on outside of the “West”…. Millions of vehicles with no emissions equipment…. More coal power plants every year…. And here we just pay more and more and more.

What is coming is far worse…. You are absolutely correct there and it will crush the existing automotive industry…. People may start valuing older cars and paying to refurbish them. China is waiting for these rules to come on line so they can flood the market with cheap EVs (they have been buying up the EV supply chain for years).

If the administration and EPA leadership doesn’t change the US auto industry will be decimated in a decade. Or less….

 

Surely the ECU would disable AFM if it detected lack of load (solenoid), because without an essential component of the system functioning it would not try to activate anything else.

The question is if this would be grounds for limp mode, or if it would happily run normally with a check engine light.

Looks like a dedicated fuse for those solenoids?

 

There are literally millions of small block GM engines will hundreds of millions of miles with AFM. Failures are extremely rare. I'd much rather have AFM that start-stop.

 

So, I would take the auto start/stop over AFM. In addition, I think AFM is totally stupid as it is less effective in the conditions where the gigantic V8 is least efficient. City traffic. Stopped at a light, car stays in V8 mode. Why? Shouldn't it go into V4?

 

City traffic is exactly where AFM won't work. Any time the engine is under load or expected to accelerate the C8, it needs to shut off.

 

I don't like how AFM feels... but part of that seems to be that more often than not, when it drops to 4cyl mode, it does it at the same time it shifts up a gear, so you hear the change and you feel it too... I can just put it in manual more or track, but then you run higher RPM and waste fuel when cruising along. Would love to disable it in Sport mode, so you get the lower revs, but without 4 cyl mode...

 

I don't think you can assume that this fuse only fuses those solenoids. Its an ignition fuse. If I understand the code correctly, F34RA is in the rear fuse block. In the Owners Manual it is described as (in the 2021 manual) O2 sensor/Engine oil/Canister purge/Activefuel management. And that same fuse is shown in other schematics. Pulling would definitely set some codes.

Your thought that disabling a component of AFM might shut down AFM. You could try disconnecting the connectors to the AFM Exhaust Flow Control Valve Actuators on the muffler. They would default to open as I understand it. And it will set a code. But maybe it would affect AFM operation - maybe not. Long shot.

 

It should be in V4. But, it is in V8 instead. I don't know if you've driven through MD but the light delays there are 1 minute or more. I'd rather have on/off or V4 when stopped. The moment I take foot off the brake, it could switch to V8. GM choices make no sense to me when everyone else uses the on/off this way.

 

^^^^
Since they have the fuel consumption data felt GM knows best why at idle all cylinders firing are better overall than at that low rpm having the V8 missing on 4 cylinders.

But you're right re Stop/Start great when you have many stops. From my observation, with ~1000 miles on my E-Ray, looks like they are using what I know my wife's BMW X5 SUV does to start the engine. It's mostly done without the starter motor! They stop the engine right after a combustion even and capture that high combustion pressure. Then, just as soon as you foot is of the brake pedal that pressure turns the engine and it starts. Cannot get my foot off the brake and on to the gas pedal as fast as the engine starts with both. Seldom hear the starter motor.

Similar in concept to what was used in WWII to start airplanes, tanks when eclectic power was not available. It was called the Coffman starter and used a special blank ammunition shell that fired into a cylinder at TDC. In fact, at least some, if not all the British Spitfires used that method versus an electric starter motor. Saw a pic where it had a multi-shell cylinder so if the first didn't do the job had several more!

I also see in MY Mode set to Sport it does stay in V4 longer. The electric motor, powered by otherwise wasted braking energy, is used. Sometimes with quite a bit of HP, more than the LT2. The center display where you have two graphs showing power from each, is neat!

 

In my AMG turning the auto shut off is part of enabling my “individual” setting so it gets turned off every time I get in the car….

In my wife’s car I have to find the “off” button to disable the feature…. Nothing annoys me more than forgetting and coming to a stop and the engine dying….

But at least I can turn it off…. We can’t turn AFM off… if we can’t buy cars without these “features” we don’t want we should at least be able to turn them off…

I only have a handful of miles on my C8 and already I find myself looking down checking if the V4 light is coming on and trying to drive around it…. According to the manual driving in Sport mode or Z mode with engine in Sport, at least limits AFM to gears 5-8 vs Touring or My mode which allows AFM to activate in gears 4-8….. Track or manual mode is no AFM…. I like driving in manual mode but I wish the car had a normal shift lever. I learned to drive on manual transmission cars and almost always drive with my left hand so my right hand is not usually on the wheel for right paddle upshifts (first world problems…. I know…) but it’s hard to break the habit when you learned to drive that way…

 

^^^^
Had some similar feelings. BUT after I got my 2020 C8 Z51 and now E-Ray don't miss stirring a stick. Love the DCT technology. Below is a summary of my 64 years driving!

Suggest watching this video. It's what got to using Z-Mode Power set to Track a month after I got my C8.

You Tube

SIDEBAR
First, until I got my 220 C8Z51, EVERY DD I had for ~60 years was a standard shift. Many fast cars, like the Hot Rod I built when I was 16 and stuffed an Olds engine, I had bored 1/8-inch etc! Yep, couldn't wait to get 4 on the floor after going from the '41, 3 on the floor to my '50 Ford 3 on the tree. That was my 1st new car a '67 Chevy.

Heck was enough of a purist that did not have a car with hp robbing AC until I moved South in 1985. Had a black turbo pocket rocket I brought from CT. Lived for 2 summers without AC, which is crazy in SC! Bought my 1st Vette a 1988, to get AC. Only 15% of us bought standard shifts that year as it was the exact same price as automatic (data from Corvette Black Book) as GM stopped making standard transmissions for high powered car some years before. Mine had a true 7 speed built by Doug Nash, a Michigan Hot Rodder. It was essentially an old GM beefy 4 speed he had an electric activated OD built into the tailshaft. OD could be activated with a button on the shiftlevel in 2nd, 3rd, and 4th. IF you split shift (like an 18-wheeler driver) you'd get 7 well-spaced gears!

My '93 Vette had a ZF 6 speed followed by a C6 Z51, 6 speed bult by Tremec. The next two Vettes were C7s with Tremec 7 speeds. Although I was very good at heel toe (or toe side of foot with well-spaced pedals) loved automatic Rev Match. Never used thru higher than 5th gear except when on a Freeway where when in 7th I downshifted directly to 4th (direct drive) at an exit with a perfect match regardless of speed.

When the C8 was announced as not having a standard trans, (about 2 years prior to full details) was concerned GM would use the "slushbox" they designed with Ford turned into a transaxle for cost reasons. If they had, would be driving a Porsche. That goodness it's a DCT.

For the 1st month I drove in MM until leaving the stop sign at the end of our rural road, merging into ~70 mph often heavy traffic. With the wheel turned, accelerating the upshift paddle is out of position I hit the rev limiter as 1st reaches that at 34 mph in the blink of an eye. No fun with cars coming up very fast behind! Found Z-Mode Power set to Track I set ride to Sport. It's smart and shifts by itself just before the rev limit! Often drive in that Mode. But I also drive in MY Mode where it uses all 8 gears and V4. Would NOT KNOW it's in V4 unless I looked at the dash.

My E-Ray uses V4 even more as it utilizes the electric FWD motor instead of switching to V8 or downshifting when you come to a small incline. It also has Stop/Start and like my wife's BMW X5 SUV that starts after a short stop with captured combustion presume it appears to do the same thing. Happy to accelerate with otherwise wasted braking energy and saving fuel (not for money but just smart wasting less gasoline energy!)

Yep, only drove stand trans cars as DDs for ~60 years from my 1st, built in High School


When 2 years before the details were out about the C8 it was clear there would be no standard trans, was concerned they would turn that "slushbox" designed with Ford into a transaxle keep costs low. When a DCT was announced thought heck I leaned to go from a "slip stick" in College to a TI-59 programable calculator to the 1st PC in OH I bought for our R&D Lab from Radion Shack! Now can't operate my part time Internet business without 2 PC's and iPad (when I travel) and reluctantly my 15Pro iPhone I only use when I leave the house. Don't use the cell phone in The Vette or respond to foolish text messages. Unlike many, where the cell phone has become an appendage, been semi-retired since 2000 and will not be tied to the device! Note PIC posted ~2019 before the C8 was produced and I got my 2020 C8 Z51 Now learned no need to even pull paddles. Just drive in Z-Mode Power set to Track.

 

So basically you got AFM all the time. And, like you said, not AFM in gears N-1-2-3 which is stop/go traffic.

 

You get AFM when cruising at steady speed in any of the gears (and driver modes) where AFM can be enabled if you are in automatic shift mode. It may stay in AFM with very very slight acceleration, or maintaining speed on a very slight incline, but nothing more than that. More than that and it exits V4. It always exits V4 with no throttle. And there is a duty cycle. For steady cruising, every 10 minutes it will exit V4 for one minute.

 

So Z-Mode in automatic transmission disables AFM? I thought you HAD to have it in manual regardless of the settings? Also why wouldn't Track Transmission save in My Mode? Isn't that the whole point of My Mode to setup exactly what you want every time hence disabling AFM with Track Transmission.

 

Z-Mode ONLY does not go into V4 IF you set power to Track. The advanatge over setting in Track Mode is you don't have to live with a very stiff Track Ride. i have mune set to Sport but can also set Ride to Touring IF you have MRC. If you don't have MRC the ride is the sae in Track or Tiuring as there is zero control of Ride.

MY Mode is similar to Z-Mode BUT you cannot set Power! So if you set in in Sport, as I have you get Sport ride, but it shifts to all gears AND V4.

 

Thanks for the clarification my car should be built this week (fingers crossed I have a TPW of 4/8) so can't wait and trying to learn as much as I can. My Raptor doesn't have AFM but does have start stop which I disable permanently with Forscan. Someone needs to develop GMScan lol.

 

Have never heard mine and couldn’t care less. My Guess is the 14 speaker stereo system has something to do with it!

There must be a thread on here where people are whining about something important.

 

My experience with forums (I'm a member of too many!) is that 90% of the complaints are immaterial.