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My 2023 C8 is getting built end of August and I have reservations about the “gas saving” V4 mode in a $100k sports car. Not something I want any part of even on a long trip on a freeway. I’m old school and can’t imagine something like this being any good for the motor and I definitely don’t want the car in 4 cylinder mode at any time while I am trying to enjoy the vehicle. What’s next- turn the car off when it stops at a red light? This is a Corvette, right? Is there someway to turn this off?
My 2023 C8 is getting built end of August and I have reservations about the “gas saving” V4 mode in a $100k sports car. Not something I want any part of even on a long trip on a freeway. I’m old school and can’t imagine something like this being any good for the motor and I definitely don’t want the car in 4 cylinder mode at any time while I am trying to enjoy the vehicle. What’s next- turn the car off when it stops at a red light? This is a Corvette, right? Is there someway to turn this off?
I understand your concern.
One of my cars, I'm driving an Aston Martin DB11 V12. Not only does it have the start/stop, it also deactivates half the cylinders at certain times making it a straight 6 CYLINDER!
In its defense though, having it on the Florida highway 75 going from Sarasota to Ocala at 95 to 115 mph a lot of the way, I know there were times it had to have been in 6 cyl mode, but be darned if I could tell. Every time I wanted 600hp, I got it.
I am VERY automatic now - when I get in I buckle my seat belt, hit the start button, shut off auto start, hit the D button and go.
My 2023 C8 is getting built end of August and I have reservations about the “gas saving” V4 mode in a $100k sports car. Not something I want any part of even on a long trip on a freeway. I’m old school and can’t imagine something like this being any good for the motor and I definitely don’t want the car in 4 cylinder mode at any time while I am trying to enjoy the vehicle. What’s next- turn the car off when it stops at a red light? This is a Corvette, right? Is there someway to turn this off?
I understand your concern.
One of my cars, I'm driving an Aston Martin DB11 V12. Not only does it have the start/stop, it also deactivates half the cylinders at certain times making it a straight 6 CYLINDER!
In its defense though, having it on the Florida highway 75 going from Sarasota to Ocala at 95 to 115 mph a lot of the way, I know there were times it had to have been in 6 cyl mode, but be darned if I could tell. Every time I wanted 600hp, I got it.
I am VERY automatic now - when I get in I buckle my seat belt, hit the start button, shut off auto start, hit the D button and go.
I'm betting you'll not notice V4 mode.
Last edited by BlindSpot; Jul 22, 2023 at 05:59 PM.
I always drive in Z mode, track or manual to stay out of 4 banger mode, since I put on aftermarket exhaust I know if I forget as my exhaust note changes
I always drive in Z mode, track or manual to stay out of 4 banger mode, since I put on aftermarket exhaust I know if I forget as my exhaust note changes
How do you avoid V4 in Z mode?
I run in Z and mine switches in and out of V4?
I have a 2023.
One of my cars, I'm driving an Aston Martin DB11 V12. Not only does it have the start/stop, it also deactivates half the cylinders at certain times making it a straight 6 CYLINDER!
In its defense though, having it on the Florida highway 75 going from Sarasota to Ocala at 95 to 115 mph a lot of the way, I know there were times it had to have been in 6 cyl mode, but be darned if I could tell. Every time I wanted 600hp, I got it.
I am VERY automatic now - when I get in I buckle my seat belt, hit the start button, shut off auto start, hit the D button and go.
I'm betting you'll not notice V4 mode.
Turning a V12 into L6 is a different story though. L6 as half of an V12 is perfectly balanced, but a V4 is far from that. And IIRC the GM system is not capable of alternating which cylinders to deactivate which can lead to uneven wear
We know some customers are not fans of AFM (Active Fuel Management, otherwise known as cylinder de-activation). They worry it will sound bad, or feel bad as it transitions in and out of V4 mode, or just don't like that the engine doesn't always run on all cylinders. Manufacturers around the world are being put under tremendous pressure to reduce fuel consumption and greenhouse gases. As a result, you see a massive move to electrification, hybridization and small displacement charged engines. General Motors is fully embracing the initiative and has a stated goal to get to a zero emissions future.
So how does Corvette fit into this picture? Even before global greenhouse gas concerns became mainstream, Corvette prided itself on efficient operation. After all, low mass, low drag and efficient engines make for a better sports car. There are a lot of ways to get fuel efficiency and some of them negatively impact the driving experience. Our manual transmission skip-shift we had for years was not a customer favorite, but it helped economy and kept us away from gas-guzzler taxes. The bottom line is that we have to make choices that balance the owner's experience (including operating cost) and our impact on the planet.
Our AFM system is very effective on the small block V8. It lets us close the valves on the de-activated cylinders so the cylinders act as air springs. When the engine rotates we get energy back as the compressed air in the cylinder expands. Other manufacturers just stop fueling the de-activated cylinders and so don't get much fuel savings. The reason 4-cylinder operation is more efficient is that the active cylinders are worked harder with a greater throttle opening. That's like taking a restrictor out of the system saving pumping losses. On Corvette, AFM saves more fuel than start/stop, a feature becoming very prevalent in the marketplace. For many cars, start/stop is a great choice because it is almost transparent to the occupants. Not so on a Corvette. Our engine has a lot of character, so when it stops running it is very noticeable. We have received a lot of very strong input from customers that they would not like it.
One of the innovations on the 2020 Stingray is the integration of AFM with a DCT. We a quite proud of how seamless we've been able to make it. We believe we are getting the efficiency benefit with virtually no compromise to the driving experience. Numerous drive impression articles have been written and I do not remember reading any negative comments about it. Bottom line is that we must balance conflicting demands and make smart choices so we can continue to offer the driving pleasure of a naturally aspirated V8 engine.
So now to the heart of your question. Yes, when you are in manual mode the engine stays in V8. That is true either by hitting the "M" button or by entering "temporary tap" by pulling one of the paddles. Temporary tap will revert to "Drive" after about 5 seconds if you don't request an additional shift in that time. AFM is also de-activated in "Track" mode. Since PTM is only available in Track mode, the answer is yes to that one too. If you are in PTM, it will be V8 only. New for 2020 is the "Z" mode which will come from the factory set up as an extra sporty mode including shift schedules pulled from the "Track" mode, so that will be V8 only. Of course, you can customize "Z" mode any way you want, so if you elect another shift pattern, AFM will return.
Turning a V12 into L6 is a different story though. L6 as half of an V12 is perfectly balanced, but a V4 is far from that. And IIRC the GM system is not capable of alternating which cylinders to deactivate which can lead to uneven wear
Yes, good points. On the Bentley CGT with W12, it too splits in half running only the 6 cylinders on one side and not random cylinders. I'm either getting too old to notice, or it's just so smooth on these 12s I cannot tell, and both cars have a sport, sport+ mode where cylinder deactivation is not used, but I am never in these modes on the highway. I haven't personally experienced V4 in the C8, but many claim it is seamless.
Just out it in "Track Mode" when letting car shift itself or "Manual Mode" when you want to paddle shift. Either way disables V4 mode. On the highway I usually run it in Sport or Z-mode with your preferred settings, it doesn't kick in to V4 mode very often and if it does a very tiny bit of throttle stops it.
I have AWE Track exhaust which does not have any exhaust valve modes (it is always LOUD) so V4 mode would be more of an issue with my car and I am fine with it or working around it. I had the stock NPP exhaust (too tame for me) and V4 mode was not noticeable as the car goes quiet when it goes it to V4 mode.
I have videos on youtube in V4 node with my AWE exhaust, search under Howard AWE Track
That said, if someone doesn’t want to buy a C8 because of AFM, then that’s their prerogative. Some find it incredulous that a V8 sports car should ever operate on 4 cylinders under any circumstances. However, the system is rather seamless and one would be hard-pressed to know when AFM switches to V4 unless they are watching the indicator or just happen to hear the slight vacuum sound when valves close (imperceptible if listening to the sound system).
AFM is not a big deal to me personally. If it’s a big deal to you and you are on the fence about buying a C8, then don’t buy one.
I would think with tuning available, AFM could be disabled for any drive mode and not have the restrictions of some of the "work arounds". Really pricey though to spend $1500+ for an unlocked ECM, or is that just for unlocking your own ECM? Hundreds more for "Credits" to license and probably another couple hundred to actually have somebody do it. I don't remember how much I paid for a tuning device for my Silverado to turn off it's AFM, but it was nowhere near what it would cost for the C8.
You will be fine, the car will be fine, and you will come to LOVE the 27 MPG on long trips in touring mode.....versus the 13 I get driving around in Z-Mode with my foot always on the floor
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Slideshow: A Jaguar designer's personal project imagines what a modern front-engined Corvette might look like if Chevrolet revisited the golden age of the Stingray.
V4 & V8 Mode
