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If you're like me and want to avoid V4 mode, especially during the 500 mile break in, there is a good way to avoid it without having to drive in Z mode with power set to track (since this can over-rev the engine during breakin if you're not careful).
Just hit the M button to switch to manual mode. I used Mymode with the power set to it's highest setting and just stayed in Manual mode for shifting through the 500mile break in. Now this of course can over rev the engine too so you have to be mindful and upshift at/before 4k RPM or so, but it's a lot easier than Zmode in my opinion. I accidentally hit 5k RPM twice and 6k RPM once during break in but only VERY briefly, backed off the throttle right away when it happened (once was an inadvertent downshift that threw it up to 5800ish instantly).
This method was nice for a number of reasons. It allowed me to cycle through the gears a lot more than the car would on its own in tour or sport, and let me stay in a lower gear for long periods (like cruising at 60-70mph give or take for 10+ mile stretches of hill country roads where I would alternate between 5th, 6th, 7th, and 8th gears and would downshift on uphill slopes to avoid "lugging" the engine).
My C8 spent a grand total of maybe 30 seconds in V4 mode in its first 530 miles, and I feel like my break-in was extremely thorough in exercising all the gears at various RPMs.
Tl;DR --- Manual mode with the paddles (in any drive mode) is outstanding for preventing V4 mode!
I simply don't understand the preoccupation with avoiding V4 mode during break-in or any other time. When you want V8 power, your right foot takes care of that.
It was more understandable with the C7 because the transition was a bit rough, which is not the case with the C8.
I simply don't understand the preoccupation with avoiding V4 mode during break-in or any other time. When you want V8 power, your right foot takes care of that.
It was more understandable with the C7 because the transition was a bit rough, which is not the case with the C8.
I wonder which is worse: accidentally hitting 6,000 rpm when break-in is supposedly limited to 4,000 rpm (while trying to avoid V4) or just letting the engine go to V4. My guess is neither is harmful but 6000 rpm is probably worse than coasting for a few minutes. During my break-in while varying speed I saw V4 light up periodically and felt no change between V4 and V8 since I was varying speed lightly.
The ONLY time it goes into V4 mode is when you are at absolute dead steady speed and the only throttle applied is for maintaining that exact speed. Which is what you are attempting to avoid in break in ANYWAY. My point is, if you go "around" the AFM and are at a dead steady speed of say 58 mph, you aren't varying the engine speed then either. Way too much thought goes into this and a bunch out there think they have some secret recipe to a successful break in. I just saw some post saying all the variations the owner did and now pronounces his car burns no oil! Hallelujah, the secret recipe worked!.........oh wait, I didn't follow his recipe at all and after 4,500 miles mine doesn't use any oil either. Huh, maybe it wasn't the secret recipe that broke in the engine correctly after all.
^
Yep, I can see V4/V8 transitions actually being a helpful part of the break-in process of varying rpm, etc.
Maybe if I ever intended to use it, but I dont. If I wanted a 4 cylinder I'd buy a 718 cayman or drive the ecoboost mustang I use as a DD. I bought a V8 I want all 8 cylinders, all the time. This topic has been beaten to death though. I was just sharing my experience in case any like-minded people would be interested. I didn't share it to hear how I should allow V4 mode. I have zero interest in it now and never will.
Originally Posted by Phil1098
The ONLY time it goes into V4 mode is when you are at absolute dead steady speed and the only throttle applied is for maintaining that exact speed. Which is what you are attempting to avoid in break in ANYWAY. My point is, if you go "around" the AFM and are at a dead steady speed of say 58 mph, you aren't varying the engine speed then either. Way too much thought goes into this and a bunch out there think they have some secret recipe to a successful break in. I just saw some post saying all the variations the owner did and now pronounces his car burns no oil! Hallelujah, the secret recipe worked!.........oh wait, I didn't follow his recipe at all and after 4,500 miles mine doesn't use any oil either. Huh, maybe it wasn't the secret recipe that broke in the engine correctly after all.
I never claimed that my way was the right way, the best way, or that its any sort of secret method to a better break in. If someone like me is interested in avoiding V4 mode, manual mode with paddles is great whether during break in or not.
If they don't, so be it. I do feel like I varied my speed a LOT over the 500 miles. Just because I had periods cruising at a steady speed and would shift gears to vary RPMs, doesn't mean I didn't also slow down and speed up. Lots of hairpin turns, twisty segments, and hills in the hill country. I did 90% of the break in miles on these roads, where speed limits were 35, 45, 55, 65, and 70 with turn signs dictating speeds as low as 15 at times. I like how I did my break in, but I made no claim that others should follow suit. Do as you will with your cars guys. I was just sharing my experience.
That's nice for the C7, but the C8 has no manual transmission - just the DCT. Here's what Tadge had to say about the C8:
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.
Full C8 AFM discussion:
Can AFM be turned off by putting the car in manual mode? How long before it goes back to auto mode?
Assuming I purchase a Z51 with magnetic ride, can I disable AFM by putting it in PTM?
Tadge answered:
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.
Maybe if I ever intended to use it, but I dont. If I wanted a 4 cylinder I'd buy a 718 cayman or drive the ecoboost mustang I use as a DD. I bought a V8 I want all 8 cylinders, all the time.
I just want to understand how you would know how many cylinders are being used when the car is at a steady state of speed with 0.0 g of acceleration? It's the ONLY time AFM works, so if you start to push on the throttle it's back to V8. I'm really trying to understand. I mean, when I stand on it I HAVE a V8 with all the power it can make, when my son stands on his EcoBoost Mustang, it's still a 4 cylinder.
Wow, now I'm really confused. I drove the first 500 miles without even knowing that I was breaking in my car all wrong because I wasn't forcing it to stay in V8 mode. Now I read that in V4 mode the 4 working cylinders are having to produce more torque than they would have to in V8 mode, to compress the air in the unused 4 cylinders with shut valves. So, double jeopardy for being in V4 mode.
Unless of course, the working 4 cylinders are selected randomly to even out the wear. Without that, half of my engine is going to age prematurely! I'm going to read my warranty very carefully to find out which half of my engine is covered.
If you're like me and want to avoid V4 mode, especially during the 500 mile break in, there is a good way to avoid it without having to drive in Z mode with power set to track (since this can over-rev the engine during breakin if you're not careful).
Just hit the M button to switch to manual mode. I used Mymode with the power set to it's highest setting and just stayed in Manual mode for shifting through the 500mile break in. Now this of course can over rev the engine too so you have to be mindful and upshift at/before 4k RPM or so, but it's a lot easier than Zmode in my opinion. I accidentally hit 5k RPM twice and 6k RPM once during break in but only VERY briefly, backed off the throttle right away when it happened (once was an inadvertent downshift that threw it up to 5800ish instantly).
This method was nice for a number of reasons. It allowed me to cycle through the gears a lot more than the car would on its own in tour or sport, and let me stay in a lower gear for long periods (like cruising at 60-70mph give or take for 10+ mile stretches of hill country roads where I would alternate between 5th, 6th, 7th, and 8th gears and would downshift on uphill slopes to avoid "lugging" the engine).
My C8 spent a grant total of 30 seconds in V4 mode in its first 530 miles, and I feel like my break-in was extremely thorough in exercising all the gears at various RPMs.
Tl;DR --- Manual mode with the paddles (in any drive mode) is outstanding for preventing V4 mode!
Funny, I drove in manual mode for a month when I got my C8. My main reason is ALL my DDs in 60 years driving had a 3rd pedal and was reluctant to buy the C8. However after the C8 launce and the under 3 second 0 to 60 took the chance and placed my order. (PS love the DCT now.) Had a person who was like myself and only had standard shifts. He had a Ferrari and said he loved the DCT BUT always drove in manual mode. So for that month Manual Mode is what I used.
BUT soon found the 5.17:1 dif ratio and 14:1 torque multiplication in 1st required pulling the upshift button at ~20 mph to stay below 4000 rpm. Easy much of the time BUT not when making a turn from a stop light or stop sign. Upshift paddle is out of position! Easy to exceed 4000 rpm. That was especially an issue when leaving the stop sight at the end of my street and merging into ~70 mph, often heavy traffic, on a 4 lane divided highway. I accelerate to merge and after the 500 mile break-in I even hit the rev limiter several times. NO FUN feeling like you hit a brick wall with traffic coming up fast behind!
Now use Z-Mode powertrain set to track (in my case Ride set to Sport) and just put my foot to the floor and it shifts just before redline. It also does not go into V4 Mode. But unlike my two C7's where I just never drove in ECO AND could feel the V4 transition when I did, it's absolutely a non issue in the C8. The other drive mode I use is MY Mode set to Sport. Unlike Z Mode where it will not use 7th and 8th or V4, it uses all 8 gears and V4. Cannot tell when V4 occurs other then the dash indicator. So after 15 months I don't drive in Z Mode to avoid V4 just to have a more aggressive drive and have it shift up and down as I did my two M7 C7s!
Yep still pull the paddles from time to time in both drive modes. If in Z Mode and just cruising for a long section of road, pull the upshift paddle and go into 6th or 7th. In My Mode, when making a turn, pull the downshift paddle before turning (in Z Mode no need as it downshifts on it's own at higher rpm.) In Z Mode with aggressive braking (as when I lever the ~70 mph traffic on the highway in front o the rural road) I brake aggressively and it down shifts two gears and rev marches in the blink of and eye!
I adjusted my hand position when turning from a stop light to hit the paddle and upshift from 1st to 2nd before 4k rpm without any issues. The paddle can be pulled with 1 finger, didn't take much effort at all.
^^^
Yep, did the same for that 1st month when casually pulling away from a stop light or stop sign. BUT with heavy traffic in both directions, accelerating into packs of ~70 mph traffic was another. Particularly in the summer months (although now often in most seasons) was not easy leaving the stop sign at the end of the rural road we live on when merging onto a 4-lane divided highway. Although we're ~1 hour from Myrtle Beach, that highway is what cars, motor homes etc use when going or coming from I95 South and Route 20 to the Beach. The packs of traffic going ~70+ mph often leave few and small gaps. Have to accelerate rapidly to merge. In my case, often turn left so cross and traffic gap in two lanes and merge into the lanes on the other side of the narrow divider. Have to accelerate quickly and turn the steering wheel rapidly not slow or casual.
Much easier to just press the Z Mode button on the steering wheel and let the DCT shift just before the rev limiter hits! Yep at ~70 mph in the blink of an eye!
Also don't want to have traffic slow excessively for me when returning home so with Z Mode Powertrain set to Track I brake aggressively and the DCT downshifts 2 gears (or even 3 depending on my speed) and rev matches in the blink of an eye. I call in Rev Match Music!
If running in V4 mode during the initial 500 miles was truly detrimental to the engine’s longevity, I’m sure GM would have coded the C8’s operating software to not allow V4 mode until the 501 mile. After all, GM has to warranty the engine for 60K miles. It would not be in their best interest to allow V4 mode during the first 500 miles if it would increase the number of warranty repairs. Pretty sure this much ado about nothing.
Absolutely no reason to avoid the V4 mode during break in period. Just drive the damn thing....
Well I'm avoiding it permanently so I may as well avoid it during break in. As far as I'm concerned I'd rather pay the gas guzzler tax than have it on the car at all.
Originally Posted by Mr Snappy!
Maybe skip the click and the troll post if you disagree with the thread. You do you boo and enjoy your V4 mode if you like it. I'll pass.
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A good way to avoid V4 mode
