Playing with V4/V8
Thread Starter
Burning Brakes
Joined: Mar 2021
Posts: 998
Likes: 388
From: Tyrone, GA
Playing with V4/V8
I have been experimenting with driving in "D" and watching the V4 mode pop up and I have found that if I don't try to accelerate in V4, I don't get any lag or disappointing acceleration. What seems to work well is to downshift with the paddle while in V4 mode just before you want to accelerate or go up a hill. This way the engine and transmission are in a stable condition with no load on the engine or torque converter. Then when you downshift, the tranny goes to "M" and the engine goes to V8 with no load on either the engine or the torque converter. Think of the paddle as a passing gear while in V4 mode and it works out with no noticeable hesitation or droop. Then after you have passed or climbed the hill the tranny will automatically go back into "D" and the V4 mode will come back on if the road is flat. I think most of the torque converter issues come from trying to accelerate while in V4 mode. Give it a try and let me know what you think.
Racer
Joined: Apr 2020
Posts: 425
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From: Cape Coral,FL
What I think is V4 does way more harm then good. It causes drive train issues has a chance of destroying your motor when going from v8 to v4 and back again. For me from day one I've had a range device.
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I have the Range AFM Eliminator plugged in and do not have to worry about V4 mode. The small penalty on gas mileage is worth it to me.
Drifting
Joined: Jul 2013
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From: Windsor CA
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If the Range device was not available and a person could not "tune" it out I would have sold my 2019 GS weeks after I bought it new. No place for a V4 for me with this type of car.
Melting Slicks
Joined: Nov 2002
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From: North shore,Ma./Naples Florida
I have always used a Range in mine and never used the V4, which I also think is stupid. I do however get a little nervous when I hear some claiming that keeping it shut off all the time is inviting disaster also. I already went through all the dropped valve stress and worry when I owned the C6 Z06, and I don’t need it all over again.
Tech Contributor
Joined: Oct 1999
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From: Charlotte, NC (formerly Endicott, NY)
I have been experimenting with driving in "D" and watching the V4 mode pop up and I have found that if I don't try to accelerate in V4, I don't get any lag or disappointing acceleration. What seems to work well is to downshift with the paddle while in V4 mode just before you want to accelerate or go up a hill. This way the engine and transmission are in a stable condition with no load on the engine or torque converter. Then when you downshift, the tranny goes to "M" and the engine goes to V8 with no load on either the engine or the torque converter. Think of the paddle as a passing gear while in V4 mode and it works out with no noticeable hesitation or droop. Then after you have passed or climbed the hill the tranny will automatically go back into "D" and the V4 mode will come back on if the road is flat. I think most of the torque converter issues come from trying to accelerate while in V4 mode. Give it a try and let me know what you think.
Bill
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Melting Slicks
Joined: Feb 2018
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From: North Texas
The A8 TCC is always in a 'slipping' mode ( engaging / disengages ) usually around 10%. It is never locked up as in the past at 100%.
When you enter V4 mode the TC does this 'dance' even more ( higher % ) to help isolate the V4 engine vibrations, ie: even more wear and tear.
Do you think that GM went to this 'dance' and a steel torque tube housing instead of using the previous aluminum one just for fun and giggles? No, it was due to excessive vibration from the V4 unbalanced mode of operation.
When you enter V4 mode the TC does this 'dance' even more ( higher % ) to help isolate the V4 engine vibrations, ie: even more wear and tear.
Do you think that GM went to this 'dance' and a steel torque tube housing instead of using the previous aluminum one just for fun and giggles? No, it was due to excessive vibration from the V4 unbalanced mode of operation.
Instructor
Joined: Oct 2013
Posts: 144
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From: New Jersey
I have a 2014 m7 with 22k miles for about a year. I have never engaged eco mode to actuate the v4. I don't know if previous owner ever had either. Is there any perceived problem in never actuating the eco mode? I'm afraid if I did actuate it accidently something will malfunction. Is there any benefit to letting it run in eco once in a while?
Melting Slicks
Joined: Jan 2015
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From: Darien, IL
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I have a 2014 m7 with 22k miles for about a year. I have never engaged eco mode to actuate the v4. I don't know if previous owner ever had either. Is there any perceived problem in never actuating the eco mode? I'm afraid if I did actuate it accidently something will malfunction. Is there any benefit to letting it run in eco once in a while?
Thread Starter
Burning Brakes
Joined: Mar 2021
Posts: 998
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From: Tyrone, GA
I understand your reluctance to use the V4 mode but I have owned a GMC and Silverado trucks with it and never had an issue. Like I said, I usually use manual so I don't run in V4 mode but was only trying to see if there was a way to not try to load the tranny while in V4 mode. I believe I accomplished my aim and also I did not see any transitioning from V4 to V8 and back on normal roads. While in V4, anytime I wanted to accelerate I just tapped the downshift paddle and the car instantly went into V8 mode and then I accelerated. I am a believer in keeping any system in my car operational and exercising the V4 mode is one of them. Obviously, this system was designed for GM's mpg issue and not the owners of their cars/trucks, but it is still part of our cars and if not maintained may become a headache later. IMHO
Drifting
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From: Lake Tapps WA.
Drifting
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From: Melbourne FL
Intermediate
Joined: Jan 2024
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I use it on road trips. But I have had a few GM vehicles with AFM never had an issue with any of them. When I got my first truck I swore it was gonna blow up from all the stuff I read on the net and it never did. That said the transition on the GM trucks and SUVs is a lot harsher then it is on the vette. Not sure it's cause of the weight or the tune.
That said I have built and owned many cars that people said wouldn't hold up. I still have a stock 4l60E behind my 481hp lt1 in my 95 camaro and it has over 160k mile on it with a 3600 stall converter.
I think a lot of people abuse their stuff and find a reason to blame someone else for the failure. Obviously the lifters and other components to have a higher level of failure then older setups and some vehicles are just problem plauged the day they leave the factory. Been there got the T-shirt wore it out. But I do belive more failures happen from abuse whether it's driving hard or not doing proper service to the vehicles or trying to cheap out while doing it.
That said I have built and owned many cars that people said wouldn't hold up. I still have a stock 4l60E behind my 481hp lt1 in my 95 camaro and it has over 160k mile on it with a 3600 stall converter.
I think a lot of people abuse their stuff and find a reason to blame someone else for the failure. Obviously the lifters and other components to have a higher level of failure then older setups and some vehicles are just problem plauged the day they leave the factory. Been there got the T-shirt wore it out. But I do belive more failures happen from abuse whether it's driving hard or not doing proper service to the vehicles or trying to cheap out while doing it.