The turbocharged 2.7L I4 L3B gas engine is pretty versatile, providing motivation for both GM trucks and luxury sedans. But what makes this big four-banger tick? To find out, Engineering Explained dug deep into the GM engine technology that powers it, as profiled in this 10-minute video.
The turbo 2.7L I4 L3B GM engine, as found in the 2019 Chevrolet Silverado 1500.
For reference, the L3B GM engine is offered in 2019 and newer Chevrolet Silverado 1500 and GMC Sierra 1500 pickup trucks. It’s also standard with the Cadillac CT4-V, and is offered as an available option with the Cadillac CT4 Premium Luxury trim level. The L3B will also be offered on the next-generation GMC Canyon and Chevrolet Colorado.
The video opens with the host laying out GM’s repeated assertions that the L3B was developed specifically for truck applications, despite its appearance under the hood of the Cadillac CT4-V. Putting that aside, we get down to some of the nitty gritty info that Engineering Explained is known for.
First off, the L3B is pretty big for a four-cylinder gas engine, displacing 2.727 liters with a stroke of 102mm and a bore of 92.25mm. As such, it incorporates two balance shafts under the crank shaft to combat vibrations, which start to become an issue in big engines with a relatively low cylinder count.
Next, the video looks at the GM engine’s variable profile camshaft, which enables both power when it’s needed, and fuel economy when cruising. Interestingly, the video points out that the Silverado 1500’s naturally aspirated 5.3L V8 L84 manages to eke out slightly better fuel economy on the highway, although it’s worth pointing out that the L3B still manages superior fuel economy in the city.
Finally, the video gives a breakdown of the L3B’s which is Dual Volute turbocharger, an impressive bit of GM engine technology that maximizes the impact of exhaust gas energy by separating the exhaust pulsations to the turbine between two volutes. The end result it better response, better low-end torque, and better efficiency.
All told, this video is definitely worth a watch for those readers out there craving some nerdy details on this versatile GM engine.
Comments
Jason went a little too ‘engineer’ on this. The engineer in him sees the power and torque delivery through the RPM range and loves it. The engineer loves the energy efficiency of the 4 cylinder package. And the efficiency of the dual volute turbo.
But the real world is a 5000lb truck with a huge frontal X-sectional area that makes this little engine work hard to maintain 65mph. A lot of truck owners put wider and taller tires on their trucks (gearing the truck down, adding unsprung rotational mass, and increasing the coefficient of friction), and lift kits (increasing the x-sec area and also reducing aero) further making this small engine work overtime.
The more boost/air the turbo needs to jam in the engine to provide the power to maintain 65mph the more fuel it also has to dump in the engine. The harder the turbo and engine work the hotter it gets, ECU will add more fuel to help keep combustion cool.
Next toss a trailer on, like a boat, or a utility trailer with 2 or 3 quads, and that little engine is back outside of it’s element.
I don’t think the Silverado is the right application for this engine. It would certainly be more at home in the Colorado and in crossovers.
The 5.3 V8 is a much better half ton engine. The 2.7T will get better city mileage no doubt, but that 5.3 will clean up on the highway and when asked to work.
The 2.7 has nice low end torque and will ‘feel’ faster and nice and punchy, but punchy in a 5000lb truck means fuel chuggy. It’s not like a punchy little hot hatch where you can have some spirited driving and only use an extra half a liter of fuel.
I’m not against turbo engines, but there are some draw backs and a little engine in a big vehicle shows those drawbacks best. Similar is true with Fords same displacement (2.7) ecoboost, except twin turbo and V6. That engine has great specs, and makes for a fast truck 0-60. But holding 65-70mph on the highway or asking it to work and you’re better off with a F150 5.0 Coyote. The 2.7 is great if the truck is empty. Put 4 adults in it and some luggage in the bed and it’s no longer the nice little economy turbo. Where as a V8 you’d hardly notice a difference. The disparity gets worse when you start adding something in tow.
The 3.5 ecoboost is a great sized engine for the application – which is why I believe GM’s 2.7 will be better suited in the Colorado. I think Ford purposely put the 2.7EB in the F150 instead of their 3.0EB because they had to separate it more form the 3.5. On paper that 2.7 is almost as fast as the 3.5 but more efficient. Until you drive both and you see how much harder the 2.7 has to work and how unrefined it is working. The 3.0 would have been a better choice but the gap between it and the 3.5 even narrower. It’s like how for a long time Porsche throttled back the Cayman, they wouldn’t let the midengine younger brother overshadow the rear engine 911. Those days are gone and the Cayman can finally show it’s true potential.
I can’t wait for this engine in the Colorado, but I would never consider it in the SIlveado. Especially now that the 5.3 is throwing down 6.5sec 0-60 times (C&D, MT verified) and will cruise 65mph @ 24-25mph real world dry.
Ive put 8k on my 2020 L3B 4wd silverado. It does NOT struggle to go 65. Ive rented 2020 5.7hemi ram limited and 5,3 Tahoe after flights recently and unless the v8s are WOT the are sluggish compared to my 2.7T. Towed a 4K trailer at 80mph through the mountains 800 miles ave 13.9mpg. With trailboss lift and tonneau Im getting 20.5 @ 82mph, 22.6 cruising suburban areas, using 87 octane. Truck is light and nimble. I love it. Btw my reference point: Ive owned 60 cars/trucks, 15 motorcycles, and rented at pres. Circle status for 20 years…
While Jason covers some of the tech here he leaves out a lot of the why and what is going on with going to a 4 cylinder.
The reason for the v is not just MPG but overall cleaner or as I should say less emissions.
You are making as much power from less liters that in turns creates less emissions.
Then you add in the EPA Off Cycle Credits that add up much more to help GM in overall emissions. These are not sexy selling points but the are ways to keep higher HP viable in gas powered vehicles as emissions get tougher to meet.
As for less cylinders working harder. That is irrelevant today as these 4 cylinders are not the old cast crank, rod and piston Iron Dukes go 1984.
today these engines are built as Levels many race engine were built not very long ago. They are built to take the higher forced and are very durable.
It is no different than the many Semi truck for years that ran Turbo 4 and Turbo Diesel engines run millions of miles as they are built to take the load.
I feel this engine was targeted primarily at the mid size trucks as we now have confirmed. Cadillac using them is not a big surprise either but the Truck marketing is a problem for them if they want to appear special o4 worth the extra money.
GM has quietly and slowly reduced the 3.6 from many applications. It may not be a surprise it will vanish in the coming years.
The Silverado was just a jumping off point for th3 engine as they never expected more than 10% of sales there.
I expect most GM vehicles to be V8, Turbo 4 or electric in the coming years. The V6 May die before the V8.
I also expect the DOHC V8 May replace the cam in block V8 just for the improved emissions. At least it would not be a surprise as time goes on.
One has to wonder whether there was any debate on whether this could have been a 2.7L DOHC-4v inline 5 or inline 6 engine given the displacement size or whether it was needed at all given that GM already builds a twin-turbocharged 3.0L DOHC-4v V6; Chevrolet could have replaced the twin-turbo setup with a supercharger.
A car engine will not hold up in truck service, this is one reason the 2.7L four is scheduled for the Colorado/Canyon. Most truck owners are not drug store cowboys, but actually use their trucks for at least towing a boat, or camper.
I’d be interested in an inline 6 version of this for the Silverado. Otherwise, hard pass.
Why does no one get that this engine is meant to replace naturally aspirated v6s and consolidate engine diversity among different models. People keep comparing this to the 5.3 when it is eventually replacing the 4.3. The 4.3 is a huge v6 that is only used in trucks. The 2.7 doesn’t have to beat it’s fuel economy, but it does have to beat its emissions, which is the primary job of this engine in the portfolio. How many people buy the base engine in a full size truck given incentives and such? Might as well throw this engine in the mix for CAFE. The reason the 5.3 gets better fuel economy on the highway is because it can be less than 4 cylinders with dfm vs afm and it isn’t forced induction. The 2.7 probably makes more power than the 5.3 at a certain lower rpm as well considering its running at more than just atmospheric pressure 14.7 psi. The 5.3 still has peak numbers because of cylinder count. The biggest mistake gm made wasn’t putting this engine in the Silverado, but rather not putting the 10 speed behind it from the start.
Another GM mistake. Customers do not want that engine in a full size vehicle. Durability issues will also be a area of great concern The leadership that made those decisions to put that engine in full size vehicle should be looking for a new job.
How is it a mistake? It’s an option. You don’t have to buy it. the V8 is still available, If no one buys the turbo 4, then GM will drop it.
In just a full size vehicle?
I always wanted my (not full size) Chevrolet to be inspired by tuner Civic motors /sarc
Comment for Andrew.
If you don’t think this truck will tow with the 2.7l turbo watch TFL truck with it towing 7000 pounds up the Ike gauntlet.
TFL truck also did a highway fuel economy test where it got 2 miles per gallon more than rated and came in at over 24 mpg highway for a 4 wheel drive truck. This test also included a Ram Rebel which was also rated at 22 mpg hwy. However the ram came ended up more than 5 miles per gallon less than rated and didn’t even make 17 miles per gallon.
With more horsepower and torque then 1st generation Colorado V8 5.3 that’s not bad for about half the displacement. 100% torque at 1500 rpm that works for me.
With 0 to 60 times only 2/10 of a second slower than 6.2 l V8 Silverado that’s pretty impressive. When you consider the cost of a 6.2 l V8 equipped Silverado at $15-20K or more, it becomes a great deal.
If you need more horsepower and torque to do more work buy the bigger engine if you don’t the 2.7 does a lot.
I didn’t say it can’t tow.
Just that it isn’t well suited.
Like I highlighted in my original comment, if you get caught up on the paper specs it’s a fine motor, but go drive one of these small turbo engines in a half ton truck, put 800lbs in the bed or a boat out back and tell me how those paper specs are treating you.
Ram gives the Rebel the same EPA est. as a non-lifted Ram without AT tires. They cheat the sheet. GM is honest and rates the TrailBoss seperate from a standard LT.
That 2.7 in the Silverado is like the base 3
3L V6 in F150, it’s a BS engine for its half ton application and shouldn’t be bought to work.
Drop 500lbs and front profile with the Colorado and it’s more at home.
For reference:
Last I knew GM sold trucks all over the world. So, while the 2.7 liter turbo engine may not appeal to American consumers, European and Asian consumers might like it. Moreover, I’m confident General Motors put the engine through durability testing both on the dyno and on the road. GM has a multi-axis dyno that simulates a variety of engine horsepower and torque demands going up or down at hill and at an angle therein simulating possible oil starvation around a corner.
When this engine was announced well over a year ago, everyone on this forum said the same thing, why wasn’t it slated for the Colorado and the Canyon. Well it’s coming on the next refresh and it will be a big success.
My 3.0 liter in my Explorer ST pulls trailer/ boat with no problem and has 400 hp , and will hang with a Durango SRT with a monster 6.4 gas guzzler
of course this engine has its naysayers, but I haven’t spoken to one person who was disappointed with it so far. In fact the opposite. Everyone says its super snappy and handles everything. Yea if you’re towing big, its not the engine for you. We all know that. This is a great engine for people just doing light towing. Which is all you should be doing with a 1500 truck anyway.
What I find interesting is how the EPA consistently has been underrating GM’s the past 4-5 years dropping mileage ratings by as much as 3 on the same vehicles or only bumping city numbers slightly when switching to CVT’s or DFM setups and 9/10 speed transmissions. My 2017 Impala 2.5 is a perfect example. Rated for 22/31 from 2014-2017 then dropping to 22/30 for 2018 and then dropping again to 22/29 for 2019 on the same exact vehicle with the same exact engine and transmission and zero explanation for the drop! Well I have taken this car on numerous long trips, some 900 miles total with the AC blasting going 73-75 MPH and have seen 36 MPG plenty of times on both the readout and verified with calculator. So that means the EPA clowns were off by 5 on the 2014-2017 models, 6 on the 2018 and 7 on the 2019’s!
The fact that TFL achieved 2 more MPG on several highway tests on a new green 4X4 Silverado 2.7T is even more impressive considering how heavy, high off the ground they are and how much frontal mass is going down the road. We have rented many a Silverado 4X4 5.3/6 speed and 3.08 rear gears, Ram 4X4, Hemi/8 speed and 3.21 gears and various F-150 4X4 3.5/5.0 and 2.7 setups and in most every case the GM’s got their highway rating or exceeded it and the Rams and F-150’s struggled on the highway and often got lower than sticker! No surprise that Ford is in trouble again for overstating MPG on their trucks but it really should be the EPA that is checked and investigated.
The new 2021 Tahoe/Yukon/Silverado are even more suspicious losing up to 3 highway MPG and 2 in many cases with the excuse being a few extra pounds from the independent rear suspension. Well Ford has been using this setup and a co-developed 10 speed for years with the top and higher performance 3.5 EB V6 and is claiming up to 23 on the highway and 22 on the 4X4 setups so why are the GM’s rated at only 19/20 on the highway with the updated and more efficient DFM V8’s?
The EPA rating system needs an overhaul and really needs to do away with the MPG figure. If you visit the EPA web site you’ll learn that over the years the test procedure slightly changes to meet real word numbers and the outcome could be a little different. There is just too many variables to consider and depending where you live by altitude elevation, in hilly or mountainous areas, average temperature and seasonal weather impacts the ratings. The most important data is the driver themselves. You’ll see many go like a bat out of hell all the time and others will wait until next year to get moving.
Now with EV’s coming along more than ever, what does a MPG equivalent mean when the EV has a rating of 99 MPG? Now they use carbon footprint and kilowatts. Here is the EPA for EV’s, https://www.fueleconomy.gov/feg/PowerSearch.do?action=noform&path=1&year1=2019&year2=2020&vtype=Electric try to wrap your head around 148 MPGe for a Tesla 3. 24 Kilo/100 miles? Unless you are keen on math and a engineering degree, these number are useless for the average buyer.
A more simpler way could be a measuring bar. For EV’s the EPA minimum standard is say 100 MPGe. The car rating would be the percentage above this bar. For the Tesla 3 it be about 45% above the minimum requirement. Each year the bar can change as technology improves. If this helps who knows.
Too much is pounced on the MPG rating of a vehicle overall rating and many reviews will knock down a vehicle for 1 MPG difference or bring it to high heaven because it tested at 1 MPG more. As with many truck owners, MPG is not as important as reliability and able to do the job without breakdowns or premature wear.
This is a fine engine for midsized trucks but it is too coarse and unrefined for a CT4. Balance shafts help but the engine will never be as smooth as a V8, I6, or even a good V6.
Great engine, but wrong implementation. If I was in charge of GM, I would make a 2.3L version of this engine and use it in the Cadillac XT4 and put this engine in the XT5.
I bought a 2019 GMC Sierra with the 2.7 turbo, towing package, and 17” wheels. I’ve been very pleased with the vehicle. I average 18.5 mpg around town. A coworker bought a GMC Canyon with the V6. He averages 19mpg around town. I think without the towing package with the different rear end gearing I’d probably get closer to 20mpg. My previous GMC had the 5.3 and I never got better than 15.5 mpg. I have no desire to pull a trailer of any sort. I use my truck for basic transportation, trips to Home Depot, Green waste facility, and occasionally moving furniture. For this, it has more than adequate acceleration and power. It’s not meant to be for everyone. But for probably 70% of buyers it would be just fine. Now, it hasn’t been all rainbows and butterflies. At 600 miles it stopped running altogether and GM ended up having to completely replace the wiring harness. And I still don’t know about long term reliability.
2022 LTD Trail Boss Custom operated at 7000-9000′ msl in Colorado. Nothing bad to say about this machine. L3B is amazing in every aspect. I am an old GM road racing fart so tech picky. Unless I am missing something in the pictures the DI is getting some atomized charge across the valves too? Deposit correction? Don’t know but I am averaging 20 mpg and drive the speed limit when I am on a hardball road. I am in Auto and 4WD a lot. See Tech Bulletin for wiring harness contact points. Looks like they corrected on the 2022 LTD but still inspecting.
GM Engines Class Action Lawsuit is Szep v. General Motors LLC, Case No. 1:19-cv-02858, in the U.S. District Court for the Northern District of Ohio.
This one is for the engines that consume excessive oil, and then prematurely fail. The Plaintiffs have it all wrong though. GM wasn’t negligent, GM intentionally designed the engines to consume excessive oil and then fail on purpose. Republicans love making the Saudis wealthier at the expense of Americans, and they figured the destroyed engines would mean new sales.
Just wait until the lawsuits hit over thus new GM creation.