On the C7 engine.............

 

Have you ever seen a Corvette with a failure of the AFM components? Or heard of one?

 

The plant reopened on schedule.

 

No, but I haven't been following the C7. If it's the same system and the same lifters, I don't see why it couldn't happen. If they only fixed on the Corvette, that's pretty stupid on GM's part.

 

It was a noticeable sound with my stock NPP exhaust on my 2021.

I then installed a MagnaFlow system that includes 4 new valves (not simulator plates, actual working valves). I hear the same sound, so it’s how it sounds on mine.

The common denominator is the valve motors, I have heard GM has multiple vendors for them.

 

gm tech at large dealer in NJ said he has done 5 new Tahoes and pickups. All lifters and its the same pn as the **** 2012 5.3 dod lifters. What junk. Disabling it from day one is the only move. And the new gen V8 dod in the full size trucks can knock it down to 2cyl lol. That is gm grabbing for every .1 mpg it can. Unreal to me.

 

On the c7 you “felt” the change because the exhaust tone changed.....on the c8 nada.

 

I disabled AFM on my C7 via a tune on day 1 (no way to turn off AFM with an A8). My logic is that I didn't purchase a sports car with 460hp to run on 4 cylinders. I appreciate the fact that I will be able to disable it on the C8 without a tune as again, I'm not buying such an awesome sports car to run on 4 cylinders. I also worry about any long term issues it may cause that are not known as of yet. But I also have no issues with those that want to use it.

 

yep. It happens. No difference in the afm lifters of the corvettes vs every other afm lifter.

 

I actually forgot it had AFM. It's the most seamless system I have driven.

 

Not arguing with you in the least, just trying to understand the logic. I did buy my C8 because it was 500 HP, but you can't drive WOT to redline all the time or even close, especially on the street. If the car is just loping along steady at 70MPH, why not enjoy the economy? If you even start to push the throttle it is back to a V8 in literally a fraction of a second. It's not like the pedal is on the floor and you're pulling levers to try and get the thing out of 4 cylinder mode and back to 8.

 

Take a look at this video and you will get a better feel for the context of my comment. I feel very much the same about how I want my sports car to drive and I too am more interested in smiles per gallon vs miles per gallon :


When I had my C6 with an A6 I had it tuned so that it shifted at ~ 2000-2200 in each gear to keep the tranny more in the power range and reduce the number of down shifts when I got on it. In other words, I wanted it to feel more like a sports car.

Lastly, I fully appreciate all of the comments about how good the C8 handles AFM. However, in my opinion there hasn't been enough road time yet with the C8 to know if there will not be any downsides to AFM. For example, many of the A8 shuddering/failure issues on the C7 was thought to be attributed to AFM. Don't know if this is true or not, but many thought there was a correlation. I have not experienced any such issues with my A8 on my C7 and I'm not sure if bypassing AFM on it had anything to do with it.

 

None. Because the shuddering issue in all the A8s gm built was in fact a trans fluid formula that was hydroscopic. The issue was improved after 2.5 yrs with a new formula then again for Feb 1 2019 on the corvette line. What sucked was the improper diagnosis in "bad torque converters" and all that work for nothing. Even after 15 20k miles of that hydroscopic fluid, most of the converters stopped shuddering with the latest formula.

Although in a round about way you are correct. Because the pulsing of the converter clutch programmed into the tune was to lessen vibration of v4 to v8 mode. So in essence without a v4 v8 switch the pulsing would be programmed differently. None of that was seen in the 6spd trans with dod because of the more traditional design of the engagement of each gear vs the 8spd.


Whats really interesting to me is how the DCT performs after a few years in customer's hands vs the "engineers". Because they didn't pick up on crap with the A8 shudder after 100k + miles in several cars in various conditions if we are to believe that.

The more complex things are the more of Murphy's law can be applied. Which makes all electric cars just one less complicated piece to a puzzle. Taking the engine and transmission out of the mix in many all those thousands of parts gone from the mess.

 

I love AFM. I hope they keep it.

 

I'm not against going into V4 mode as much as I am against my '21 Tahoe shutting down at stop lights. I disable it every time i start the car.

 

Pretty seamless and I've only detected it when the radio was off and I was watching for it.

A bigger downside is I'm under the impression that AFM limits rpms and limits cam choices if not removed. This is my first car with it, so I'm not fully versed on the topic. Without AFM, the LT2's redline might have been 7,000 rpm.

 

I had it on my 15 C7 A8 and loved it because of the fuel mileage. I never felt or heard it engage in the four years and 38k miles that I drove that car. All I knew is that it would go a long way on road trips before I needed to stop for fuel.

 

As my granddad used to say, "Wish in one hand and s**t in the other; see which fills up the quickest." It's not there because "we" (customers) want it. Duh...

 

I wonder if they'll charge less for the non-AFM vehicles.
I've always wondered that the payback point is between the additional fuel of non-AFM and the additional costs of AFM. And that doesn't even address out of warranty repairs.

 

Yes that is exactly the reason I sold my C7, it drove me crazy when NPP and AFM collided, AFM always won. Did you have a C7? I ask because i am interested in a comparison AFM C7 v C8 from someone who hears that clunk. Maybe those who do not hear it are not so much deaf, but no NPP?

I suppose if I opted to not get NPP maybe it would not be as annoying, but that sound....