Chevrolet's New Cylinder Deactivation System Is a Game-Changer

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By Chad Kirchner

During the reveal of the 2019 Chevrolet Silverado 1500 at the 2018 North American International Auto Show in Detroit, Chevy said the new truck would have six engine options. Those are the 6.2-liter V-8, the 4.3-liter V-6, the new 2.7-liter turbocharged four-cylinder, the 3.0-liter turbo-diesel and two versions of the 5.3-liter V-8.

The two 5.3-liter options depend on which technology is used for engine management and cylinder deactivation. Chevrolet broke down the differences for auto journalists at a technical briefing Thursday in Milford, Mich., then allowed us to drive a 2019 Chevrolet Silverado 1500 equipped with the reengineered 5.3-liter V-8.

New Cylinder Deactivation System

The base 5.3-liter V-8 uses an active fuel management system that deactivates cylinders to conserve fuel. It's similar to the setup in the 2018 Silverado and can either run the truck on four or eight cylinders. The new setup, also on the 6.2-liter V-8, uses what Chevy is calling Dynamic Fuel Management. This technology can run on all eight cylinders or as few as one. But it's way more advanced than that. The oil control valves on the new DFM setup are located in the engine block and there is one for each cylinder. There are also two switching lifters for each cylinder, totaling 16. Building the oil control valves into the block shortens the distance required for the oil to travel and speeds up response time.

The firing pattern for the new engine remains the same: 1-8-7-2-6-5-4-3. What is different is that the system can control which cylinder fires in the rotation. Chevrolet uses fractions to describe which mode the engine is in. For a basic example, 1/2 mode fires cylinders 8, 2, 5 and 3 during each cycle. That's the same as V-4 mode in the older active fuel management setup. It gets more complicated when fewer cylinders are required. In a 1/3-firing fraction, the engine has to cycle three complete times for each cylinder to fire once. On the first cycle, 7 and 5 fire. On the second cycle, it's 1, 2 and 4. On the third cycle, it's 8, 6 and 3. Eventually every cylinder fires, but the system can control individually which cylinders fire on which rotation.

System Benefits

The benefits to the driver are multifold. Under the standard EPA test cycle with the old engine, the engine operated in four-cylinder mode 52 percent of the time. The other 48 percent of the time it was running as a full V-8.

Using the same test cycle, the upgraded engine operated in V-8 mode only 39 percent of the time. It then operated between four- and eight-cylinder modes 45 percent of the time. Finally, 16 percent of the time the engine operated on less than four cylinders. Using this new setup, the 5.3-liter Chevy can use up to 29 different cylinder firing patterns. In the production version of the Silverado, it uses only 17.

09-5.3L-V8 II

So why did some get cut? If you've driven the 2018 Silverado 1500 with cylinder deactivation, you can probably tell when it's running on four cylinders. It's a bit harsher and there's an audible difference in how the engine sounds. Of the 29 different firing patterns, 12 resulted in similar effects. Engineers had a primary goal of making this all imperceptible to the driver.

To assist with smoothing out the roughness, Chevy is also uses a centrifugal pendulum absorber in the torque converter like it uses in the new 2.7-liter four-cylinder and the Chevrolet Colorado diesel.

Aside from reducing unpleasantness in the cabin, why else did Chevrolet switch to this system? Improving overall performance in all driving situations. By controlling cylinders individually, the engine can improve response and efficiency more often. In fact, the system makes changes every 12.5 milliseconds. That's 80 decisions a second.

Jordan Lee, Chevrolet chief engineer of small-block engines, noted that there are nearly 66,000 lines of computer code devoted specifically to the new cylinder-deactivation function in the new engine control unit. The system takes into account more than 29,000 different variables to know which profile to run and when to run it.

Inside the truck, the V-4 and V-8 indicators are gone. Because the system is changing firing profiles on demand, there isn't a display to replace it. If you want to really geek out over this technology when you drive the truck, you'll be a bit disappointed.

How It Drives

To demonstrate how it works, Chevrolet attached a secondary display to the truck and then sent us out on the test track at GM's Milford Proving Grounds to try it out.

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The 5.3-liter feels natural mated to the eight-speed automatic, and shifts are as smooth in this truck as they are in the 2.7-liter turbo we also sampled. Additionally, it's apparent after driving just 100 feet that this new truck is significantly lighter than the current generation.

What's as impressive as the weight reduction is how seamlessly the DFM system works. If it weren't for a digital readout showing the fraction mode the computer was in (1/3, 5/9, etc.), you'd have no idea that the system was working.

The system responds rapidly to changes in throttle input. You might be running on two or three cylinders and put your foot down. It immediately is in V-8 mode with no noticeable lag. If you didn't know any better, you'd just think your V-8 was always running in V-8 mode.

GM has been building small-block engines since 1955 but continues to find ways to optimize and enhance them with the latest technology. Dynamic Fuel Management is the latest of those advancements.

We should get towing and payload performance numbers soon, along with EPA fuel-economy estimates. Although our time driving was brief, we walked away impressed with the 5.3-liter V-8 and are look forward to seeing how it holds up when subjected to the rigors of real-world testing in a few months when it hits dealerships.

Manufacturer images

Factory 10-Speed for the 6.2-liter V-8

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Factory Eight-Speed for Everything Else

08-8-speed-automatic II

 

Comments

I was talking to a mechanic yesterday who owns a 5.3 with the old school Displacement on Demand. it's a lot of complexity in exchange for the benefit.

The new DOD sounds much smoother and refined. Still a lot of complexity. Would want to see the EPAs to know if it's worth it.

Not a fan of deactivation at all. Makes me Leary of all the issues that may arise on this complexity....

Nitro- I am not either. BMW and those type of vehicles have it down pat, but it scares me to think American makes are doing it. WE are not as smart as they are.

-CT

Not smart?

@CT

Please speak for yourself

It looks like GM simplified the accessory drive to only two belts.

@ Nitro

I am not a huge fan of cylinder deactivation. I am going to take mine off here this summer, when I get my new 6.2L tuned. My buddy tuned his new Escalade and he gets 21 mpgs on highway running 80 down interstate in that GINORMOUS hog!! Plus, he said never have to worry about that engine oil consumption issue some of them are known for.

This technology is state of the art. Sounds very interesting, yet, its very complex. One little thing goes wrong, sounds like FAILURE to the engine is possible or after warranty is up, gonna be a huge bill to fix.

Although, I still give GM the biggest hand shake for sticking with the 4.3L, and their small block V8s.

I want to know how well the 4.3L does against their new 2.7L. Its the base engine, which the 4.3L used to be? We all know that little V6 is bulletproof.

For all of us who indicate concern for the advanced complexity of Displacement on Demand systems:

There is no free lunch.

Look at the performance of the current V8s. Unless you use hybrid, turbo or DoD, there's a big price to pay in terms of FE. Today's oil prices are only about 60% of the 2008 prices, but it's still enough to keep truck buyers focused on FE

So, are you willing to buy a V8 without the tech enhancements and pay more at the pump? I might be.

I love how GM is taking on the challenge of making their legendary small block V8 more fuel efficient while other manufactures has pretty much all but given up on their V8 offerings. Nothing like a V8 rumble when you put your foot into it.

@ GMSRGREAT

I second that notion!! CHEERS!

If you ask me (and I know you won't) this is just more proof that the pickup truck is no longer a working vehicle but is instead little more than a gigantic, open-bed, station wagon.

Fine. So this thing has over 300 horses at full power; so it has over 300ft-lbs of torque; it's still a tiny four-cylinder engine that drops to two cylinders when unloaded and will suck as much or more fuel than the six it replaces when under load. Obviously it's a part-time worker at best and even then not for the kinds of loads that six could handle on an everyday basis.

PAPA- of course your little brain goes back to insults, and you claim I'm the one who is stupid.

-CT

It looks like GM simplified the accessory drive to only two belts.


Posted by: George_C | May 18, 2018 8:54:25 AM

It's been that way since 2014. The 2nd belt drives the vacuum pump for the brakes.

@ Vulpine

I totally agree with you! I'm a fan off more displacement for sure. I want to see a FULL REVIEW on this thing to give it my final judgement.

But like many have said, and I will also say: So many people are buying trucks now instead of minivans and station wagons of the 90's! They don't use a truck as a truck! That is why TRUCKS have escalated in prices the past 10 years!! Just think, my dads 77 Ford brand new off the show room floor was $2300. Granted it was a regular cab truck but they are hitting OVER $60K brand new now a days.

@ Vulpine

I totally agree with you! I'm a fan off more displacement for sure. I want to see a FULL REVIEW on this thing to give it my final judgement.

But like many have said, and I will also say: So many people are buying trucks now instead of minivans and station wagons of the 90's! They don't use a truck as a truck! That is why TRUCKS have escalated in prices the past 10 years!! Just think, my dads 77 Ford brand new off the show room floor was $2300. Granted it was a regular cab truck but they are hitting OVER $60K brand new now a days.

It looks like GM simplified the accessory drive to only two belts.


Posted by: George_C | May 18, 2018 8:54:25 AM

It's been that way since 2014. The 2nd belt drives the vacuum pump for the brakes.


Posted by: Brick | May 18, 2018 11:00:39 AM


///////

I believe that's incorrect. That belt design is very similar to my 2011 6.2.

The 2nd belt is for the A/C.

Been that way for a while.

That's interesting. Hopefully they get it right.

Its nice to see GM finally get serious about getting modern engines into their trucks.

Not going with the joint 10spd auto across the board doesn't make any sense.

That's interesting. Hopefully they get it right.

Its nice to see GM finally get serious about getting modern engines into their trucks.

Not going with the joint 10spd auto across the board doesn't make any sense.


Posted by: Clint | May 18, 2018 12:19:59 PM

///////

overly complex and more prone to failure (ecoboost) with no real gain in real world mileage compared to v8's, is not what I would consider modern.

The 4.3 V6 is almost as legendary as a 350 (5.7 for the younger guys).
It's been a great engine and my '14 that I bought for a "shop truck" quickly turned into my favorite little daily truck to drive! I"m glad the 4.3 is sticking around too!

all Silverado's have tranny problems
maybe they should improve the tranny before changing the engine

all Silverado's have tranny problems
maybe they should improve the tranny before changing the engine

Posted by: Ecoboost Rules | May 18, 2018 2:02:47 PM

So what you're saying is that Chevy has a great engine.

@ Ecoboost

What transmission problems do they have? Please, explain

GM refines its V8 engines and the Ford guys get all verklempt. It must suck to only have a car engine for their half ton trucks.

Toyota Tundra
Nissan Titan

Superior engines. Superior reliability.
Superior to Ford, RAM, GM!

GM refines its V8 engines and the Ford guys get all verklempt. It must suck to only have a car engine for their half ton trucks.


Posted by: papajim | May 18, 2018 2:45:07 PM

Do you read your comment before posting?

Says the Guy who's gloating GM's 2.7L Turbo in the Silverado.

Grief...get a life.

I believe that's incorrect. That belt design is very similar to my 2011 6.2.

The 2nd belt is for the A/C.

Been that way for a while.
Posted by: andrwken | May 18, 2018 11:36:58 AM

My mistake, I knew I should have double checked. 1 belt for AC compressor, 1 belt for the mechanical vacuum pump, and the serpentine belt.

@ Frank

Do u read. This engine was built from the ground up for trucks!!!! Your ecoboosts were not built for trucks. They first appeared in cars and SUVs. What is so hard for u to understand? Or are u just upset that this little 4 cylinder makes more power than your 2.7L ecoboost V6 car engine?

all Silverado's have tranny problems
maybe they should improve the tranny before changing the engine
Posted by: Ecoboost Rules | May 18, 2018 2:02:47 PM

Tranny problems? The main "problem" that they've had is that people don't like the hard downshifts. That was the #1 complaint and red mark against GM's transmissions according to Consumer Reports. The most common issue with the GM 6L80 is hard downshifts. The most common issue with the Ford 6R80 is hard downshifts. They both exhibit the same issue. Both have TCC shudder complaints too. Funny thing is, these transmissions will exhibit this behavior yet last 200-300k miles as long as the transmission is properly maintained.

GM's 8-speed had issues with torque converter shudder that led to TSB's being issued that recommend replacing the defective TC and flushing the transmission. The design of the torque converter for the 8L90 was a new higher efficiency "pancake" TC. It had a new TCC setup called an electronic controlled capacity clutch (ECCC) that allowed a small amount of slip to help smooth out engine pulses. The issue was the friction material used. The friction material was breaking away from the TCC and clogging the transmission up. The only other ongoing issue is the occasional hard downshift that both GM and Ford transmissions are known for.

Teething issues like that is normal for any new transmission. It's not as though Ford has been off to a great start with the new 10-speed. Delayed shifts, hard shifts, torque converter shudder at highway speeds, erratic gear hunting, howling or rattling noises coming from the valve body, etc.

@brick

that's an impressive description of the issues.

Thanks for sharing that with us.

My guess (and I mean guess) is that trucks require shift programming that lends itself to harder shifts than we might experience in a luxury sedan, because a pickup or big SUV might be under much bigger loads, and have service requirements that put a greater emphasis on extended service life. That's not necessarily a bad thing, just different.

Every thing is junk motors ,transmission nothing good is gonna come out those engines. Pure junk nothing but junk.

Tntgmc, no the new 4banger does not make more power than the 2.7 ecoboost.
Reread the last bit on that from the other article.

Little jimmy, pick a lane and stick to it. Just because GM announced it doesn’t mean you have to change your mind so quick. Remember, no one wants to hear from you!

The 2016 and 2017 Silverado's and Serria are on the CR - NO BUY LIST cause of tranny problems

(the 2018's have the same tranny)

GMSRGREAT

yea! Chevy does make a great engine !
,,,,,, and Chevy has the best brake system!
too bad everything else on the Chevy is a failure, from the tranny, diff and driveline to very serious electrical issues

Old Guy is correct about the Chevy 4.3 V6,,, that's the greatest engine Chevy ever made

I admit the F-150's have brake problems, the brakes are crap and only the 8" rear diff is a problem, but the 9" diff is great
never-never-never buy an F-150 with the 8" they are trouble!

The 2016 and 2017 Silverado's and Serria are on the CR - NO BUY LIST cause of tranny problems

(the 2018's have the same tranny)
Posted by: Ecoboost Rules | May 18, 2018 11:24:16 PM


The only issue consumer reports cited was hard downshifts, which doesn't affect the longevity of the transmission. GM and Ford have been building and selling 6 speeds that downshift hard for a decade now. The problem is that the soft suburbanites are the ones buying these halftons up and they would rather have a transmission that slips into gear and chews the frictions up by 60k miles than a firm shifting automatic.

GM, payload numbers asap!

Deactivation is stupid.

It's like buying the cheeseburger, but removing the meat to save on calories or something.

You know darn well something is going to wear down or not function properly down the road. Reliability will be in question with these type of systems!

Shutting off cylinders to save on fuel is about the dumbest thing out there.

@Oxi

Please remember this day, and your comment, when the updated Tundra features DoD

I believe that's incorrect. That belt design is very similar to my 2011 6.2.

The 2nd belt is for the A/C.

Been that way for a while.
Posted by: andrwken | May 18, 2018 11:36:58 AM

My mistake, I knew I should have double checked. 1 belt for AC compressor, 1 belt for the mechanical vacuum pump, and the serpentine belt.


Posted by: Brick | May 18, 2018 5:51:53 PM

Wait until you have to change that A/C belt. The honest to god procedure I found is to roll it on (no adjustment)

I got 180k on my current Denali and won't be changing that belt until it flies off!

@ papajim

U beat me to it.

I was going to ask oxi....If Toyota came up with DoD, he would think its the best invention ever!

all Silverado's have tranny problems
maybe they should improve the tranny before changing the engine
Posted by: Ecoboost Rules | May 18, 2018 2:02:47 PM

Tranny problems? The main "problem" that they've had is that people don't like the hard downshifts. That was the #1 complaint and red mark against GM's transmissions according to Consumer Reports. The most common issue with the GM 6L80 is hard downshifts. The most common issue with the Ford 6R80 is hard downshifts. They both exhibit the same issue. Both have TCC shudder complaints too. Funny thing is, these transmissions will exhibit this behavior yet last 200-300k miles as long as the transmission is properly maintained.

GM's 8-speed had issues with torque converter shudder that led to TSB's being issued that recommend replacing the defective TC and flushing the transmission. The design of the torque converter for the 8L90 was a new higher efficiency "pancake" TC. It had a new TCC setup called an electronic controlled capacity clutch (ECCC) that allowed a small amount of slip to help smooth out engine pulses. The issue was the friction material used. The friction material was breaking away from the TCC and clogging the transmission up. The only other ongoing issue is the occasional hard downshift that both GM and Ford transmissions are known for.

Teething issues like that is normal for any new transmission. It's not as though Ford has been off to a great start with the new 10-speed. Delayed shifts, hard shifts, torque converter shudder at highway speeds, erratic gear hunting, howling or rattling noises coming from the valve body, etc.

Posted by: Brick | May 18, 2018 6:26:44 PM


You think some of those "hard downshift" issues are still related to the "clunk" all these trucks can exhibit due to driveshaft vertical movement on output shaft of trans? I know I have had times when coasting and unloading the driveshaft results in a clunk when stepping it back down and downshifting. Greasing the spline made that go away but the average truck buyer nowadays doesn't really get that in depth.

@andrwken & Brick, thank you for your posts my truck displays the symptoms you both describe. Forgive but, I am not a mechanic what exactly is greasing the spline? Can you tell us more about that? Could a dealership provide this service? Thanks guys.

@Jhawk

Google it. Your truck will run forever without that service, but it does reduce the clunk if you grease it.

@JHawk:

The guys are referring to the spines on the output shaft of the either the transmission or transfercase. More prevalent with my experience on the transfercase of a typical 4x4. Applying a special grease to those spines allowed the slip yoke of the driveshaft to move without binding and prevent what is felt like a bump on decel. It typically is a short lived repair as the lubricant becomes broken down when transmission or t/case fluid mixes with it. I haven't worked at the dealership level for many years so I am not sure if such a repair is offered anymore. However, I own a Silverado with 8 speed Trans and it exibits a bump when coming to a stop. It generally only happens during the warm-up cycle. Once the transmission reaches normal operating temp it pretty much disappears. That decel bump felt when coming to a stop on the GM 8 speed is due to the the transmission shifting from 3rd to 1st gear, skipping 2nd gear.

Oops. In my comment above, substitute the word splines in place of spines. It makes more sense with splines.

Just put it in tow haul mode. That deactivates the DOD and the DRS as well as the DOA.

Just put it in tow haul mode. That deactivates the DOD and the DRS as well as the DOA.

@Dale

Tow haul mode in most trucks takes the driver/passenger experience back to the 1980s. Not a solution.

@jhawk,

The issue I speak of may not be related to the hard shifting brick is speaking of. More of a question thrown out there for conversation.

Yes greasing the spline is a temporary fix, i have even seen some people put a racquetball in the spline to quiet it, lol. The point of removing the driveshaft spline in the truck and greasing it will more or less prove it is the issue.

Its not a GM only issue. The natural twist of the solid rear axle during load/unload requires the spline to move in and out on the output shaft. Over time a lip can develop in the driveshaft yoke which causes a clunking sound when it tries to move. Like Papa said, it will run forever, but it can be very annoying when it gets louder. It will clunk when you let off and accelerate, sometmes between shifts, anytime it moves on the spline. I greased my yoke to prove it out and mine has been quiet for over a year. If the clunk goes away, the long term fix is to replace the yoke on the driveshaft. They make a nickel plated yoke that should last longer.

@gmsrgreat

My issue is very repeatable. Not sure Im going to even replace the spline before I trade. Hot or cold doesnt matter. Sounds a little different than what your experiencing.

@jhawk

I forgot to mention. If you can pull the driveshaft, its very easy to do. Just remove the bolts connecting the driveshaft to rear axle, and slide the yoke out of the transfer case/trans. Pump some grease into the yoke connection and reinstall. I think i put 10-15 pumps in it.

If your not comfortable with that, you could probably take it to any local service and ask them to grease the yoke on your rear driveshaft Where it connects to transmission. Dealer may just push you into a new yoke. Probably a few hundred bucks at the dealer.

On the one hand, I know that complexity does not NECESSARILY result in additional problems. I have a Prius, which has many very complex things going on, and it has been ultra reliable for 180,000 miles.

On the other hand, there certainly is more opportunity for failure with added complexity. My last vehicle was retired at 327,000 miles because the variable valve timing started going gunny. I was still getting 3,000 miles per quart of oil consumed, good compression and power, but because this one mechanical feature required what would have been very expensive service, the vehicle ended up at the salvage yard.

VVT is standard across perhaps the majority of engines now. Maybe it's more durable now than in my 2002 example.

The comments about the 4.3L being this amazing thing is impressive considering the current 4.3L has not a damned thing to do with the previous 4.3L which people likely think they are talking about. I'm very happy about all of this displacement on demand stuff that people talk about and know nothing about. Without this stuff in play we would be seeing stuff like Ford sells with the biggest engine being a 5.0L for half ton trucks. The current 5.3L and 6.2L are more powerful than old school muscle cars were and yet achieve decent fuel mileage while making clean emissions. The more of this kind of stuff we see the more room we have for making big power with the trucks we buy. They are impressively powerful in stock form and more impressive when modified. If you take out the technology for fuel mileage we would be seeing the 4.3L V6 as the biggest engine possible and the 2.7L I4 as a hot dog option.



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