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GM Turbo Six Cylinder Truck Engine Project Canceled: Exclusive

GM has canceled the development of a previously planned turbocharged six cylinder engine, GM Authority has learned from sources familiar with the matter. If development had continued, the engine would have seen use not only in The General’s full-size pickups, but also in full-size SUV models.

Back in May 2022, GM Authority exclusively reported that GM was in the planning stages of a new turbocharged six cylinder gasoline engine. The powerplant would have been part of GM’s Cylinder Set Strategy (CSS), which aims to optimize engine development and production through economies of scale.

A side view of the GM 2.7L I-4 L3B Turbo engine.

GM 2.7L I-4 L3B Turbo engine

In rough strokes, the now-canceled turbo six would have been a variant of the 2.7L I4 L3B gasoline engine with two more cylinders, boosting the L3B’s already-impressive performance – one that was previously described by engineers as one that “punches above its weight, delivering surprising performance and efficiency.”

Even more intriguing is that GM’s planned twin-turbo inline-six was targeted at generating in the vicinity of 500 horsepower and 500 pound-feet of torque. That would be considerably more than GM’s current V8 engines – the naturally aspirated 5.3L L84 V8, rated at 355 horsepower and 383 pound-feet of torque, as well as the flagship 6.2L L87 V8, rated at 420 horsepower and 460 pound-feet.

Side view of the 2022 GMC Sierra.

GM’s engine lineup already features several twin-turbocharged V6 engines. A few modern examples include the 3.0L LGY, found under the hood of the Cadillac CT5-V and optional in the CT5 Premium Luxury. Another, the 3.6L LF4, powers the Cadillac CT4-V Blackwing and (previously) the Cadillac ATS-V. A few examples of this engine configuration from past GM vehicles include the 3.0L LGW, as found in the Cadillac CT6, and the 3.6L LF3, as found in the Cadillac CTS V-Sport and XTS V-Sport.

GM Turbocharged Six-Cylinder Engines
RPO Code LGY LGY LGW LF3 LF4 LF4
Configuration Twin-Turbo V6 Twin-Turbo V6 Twin-Turbo V6 Twin-Turbo V6 Twin-Turbo V6 Twin-Turbo V6
Displacement 3.0L 3.0L 3.0L 3.6L 3.6L 3.6L
Power (hp @ rpm) 335 @ 5,400 360 @ 5,400 404 @ 5,700 420 @ 5,750 464 @ 5,850 472 @ 5,750
Torque (lb-ft @ rpm) 405 @ 2,350 to 4,000 405 @ 2,350 to 4,000 400 @ 2,500 to 5,100 430 @ 3,500 to 4,500 445 @ 3,500 445 @ 3,500
Applications Cadillac CT5 Cadillac CT5-V Cadillac CT6 Cadillac CTS V-Sport, XTS V-Sport Cadillac ATS-V Cadillac CT4-V Blackwing

Various GM competitors, including Ford, Stellantis, and Toyota, have opted to develop turbocharged V6 engines in place of ever-larger V8s. As can be seen, these engines develop considerable power and torque.

Ford, Stellantis, Toyota Turbocharged Six-Cylinder Engines
Manufacturer Ford Ford Ford Ford Ford Stellantis Stellantis Toyota
Name EcoBoost EcoBoost EcoBoost EcoBoost EcoBoost Hurricane Hurricane i-Force
Configuration Twin-Turbo V6 Twin-Turbo V6 Twin-Turbo V6 Twin-Turbo V6 Twin-Turbo V6 Twin-Turbo I6 Twin-Turbo I6 Twin-Turbo V6
Displacement 2.7L 2.7L 3.0L 3.5L 3.5L 3.0L 3.0L 3.4L
Power (hp @ rpm) 325 @ 5,000 330 @ 5,500 418 400 @ 6,000 450 @ 5,850 420 @ 5,200 510 @ 5,700 389 @ 5,200
Torque (lb-ft @ rpm) 400 @ 3,000 415 @ 3,100 440 500 @ 3,100 510 @ 3,000 468 @ 3,500 500 @ 3,500 479 @ 2,400
Applications Ford F-150 Ford Bronco Ford Bronco Raptor Ford F-150 Ford F-150 Raptor Wagoneer L Grand Wagoneer L Toyota Tundra

Rear three quarters view of the Chevy Silverado 1500.

With the cancellation of the twin-turbo inline-six engine project, GM will now focus on use of its existing turbocharged inline-four 2.7L I4 engine instead, which – in its most potent, high-output guise – is rated at a very potent 310 horsepower and 430 pound-feet of torque. The General is also developing a new generation of Small Block V8 engines, which we expect to find their way into its next-generation full-size pickup trucks and SUVs.

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Comments

  1. Thanks to GM, because the good current V8 and Next Gen V8 will expose some alleged turbo inline 6 as gas Guzzler.

    GM has probably decided correctly because there are already some V6 petrol turbos at GM and why still develop a new 3.0l inline 6 if the 2.7l inline 4 is very good? You should also consider why the HP (PS) and torques have to rise higher and higher! It is more important to reduce the vehicle mass! We see you evil weight spiral at the BEV if a comparable ICE is 1000 pounds lighter!

    Why GM decided against the I-6!
    In addition, using the example of the Stellantis 3.0l Biturbo you can see that the supposedly old Hemi V8 are just as economical. Above all, the Hemi V8 N/A are also more durable and cheaper for customers. BMW and Mercedes Build I-6 that also drink petrol and diesel!

    Reply
    1. YES THANK YOU! GM STILL BUILDS TRUCKS WITH V8S FOR REAL MEN

      Reply
      1. Only difference is the reliability of a straight 6 is Legendary and low end torque.

        Reply
        1. Has nothing to do with a strait 6 configuration. The strait 6’s of the. 60’s-80’s were pushrods. They had more in common with todays 5.3 than rams hurricane I6. They also were built with a low compression ratio for emissions which naturally gives excellent long term reliability. Todays small block will be more reliable than any new I6 turbo.

          Reply
        2. There is no inherent torque advantage in an inline-6 versus a V-6. Historically people believed there was because the “legendary” I-6’s of the 60’s & 70’s ran out of breath before they hit 4,000 rpm – and it gave the illusion there was gobs of torque at the bottom when compared to an engine that could spin to 5,000 or 6,000 rpm. The falsehood was exacerbated by the I-6’s commonly being equipped with ridiculously low gears (4.11, etc.) while V8’s of the era commonly used 3.08 to 3.42 gears to balance performance and economy. I’ll acknowledge I-6’s can exhibit amazing balance and smoothness, as an inherent element of their design – but they aren’t more economical or capable of producing more torque because of that design.

          Reply
    2. No one wants the 4 cylinder Silverado

      Reply
      1. I spent a fair amount of time at 3 Chevy dealers yesterday. One had a total of 31 new 2022 and 2023 Silverado Crew cabs in both Custom and LT trims. Every single one of them were 2.7’s. The 2023 Customs were over 51K with a 4 cylinder engine, a cheap urethane steering wheel, the older interior and several other lacking features. The LT’s were over 56K with a few separate options like 20″ wheels, a bedliner and rear wheel liners. A few years ago these same basic trucks were 45-48K with V8 engines and All Star or Texas editions. The other dealers had ,ore of a mix but still on the heavy side with 2.7 engines. It sure seems that these overpriced 4 cylinder trucks are a hard sell in my area at least.

        Reply
        1. I bought a brand new 2019 LT Trail Boss Crew Cab 6.5 foot bed in Oct of 2019. Stickered for about 52K, I got it for 48K. The same truck but with the minor update to the front end and new interior is $62,080 and they are not buding. There is no way that those two updates are worth an additional $14,000. I like to get new trucks every 3-4 years. But there is absoltely no way I am paying $14,000 more dollars for basically the same truck with a new interior. They are crazy!

          Reply
  2. I doubt this decision was made in 2022. It was likely Made I 2017-2018 when the T1 platform was finializing. A 4L I6 would require a hole through the radiator. It was never in the books. Also, the new small block generation was likely started In 2019 once the 2.7 project was completed. They have had these engines built for a year by now and are testing them so their is no suprises when they release them next year

    Reply
    1. Who said 4L?It was going to be 3L.

      Decision was made recently… the 2.7L needed to prove itself, which it did and then some… so everyone started asking how to expand the formula for even higher levels of performance.

      Reply
      1. The article did.

        “ In rough strokes, the now-canceled turbo six would have been a variant of the 2.7L I4 L3B gasoline engine with two more cylinders,”

        (2.7/4)x6=4.05. They were planning on adding 2 more cylinders to the L3B to make an I6. You may recall GM’s atlas engine family in the early 2K to help with fuel economy. It was essentially 1 engine with modular parts where they had it in a 4 cylinder, 5 cylinder and 6 cylinder. The difference back then was they designed their medium SUV/truck platform underlining the H3/trailblazer/envoy/Colorado to accommodate the strait 6 from the beginning. The T1 platform under the current trucks has a shorter engine bay to increase cab and bed size, so anything longer than a V8 will be hard to fit. The 3.0 duramax only fit by having an off center oil pump and even then, is unavailable in the ZR2 because it protrudes into the lower rock guard. So their 2 options for a 6cylinder are

        -an all new I6 based off an entirely new engine layout to keep it within 3L and feature compact packing to match the duramax, but have only 5-10% more power than the 2.7…. A very exspensive option

        -a V6, which is counter intuitive as GM’s current high feature V8 weight and costs more than the 5.3 with its DOHC configuration, and after adding 4 camshafts, 3 timing belts and valence shafts has significantly more internal friction than the 2.7

        A way cheaper, reliable and common sense option is update the Small block V8

        Reply
        1. You took it literally. The article says “in rough strokes”.

          This engine was not going to displace more than 3L.

          Reply
    2. They could have kept it the same physical size as the I6 Duramax.

      Also recall from the Atlas family the 4 and 5 cyl displacements were increased to 2.9 and 3.7 while the 6cyl stayed at 4.2L.

      Reply
      1. Why have a I6 and I4 the same size? The duramax is much more complex for only 10% more displacement. They make the same power and the reason you pay the premium is because it’s a diesel. If the made a 3L i6, it would get only 10% more power, maybe less as there’s more friction involved with more rotating components. The I6 would get 335HP, and cost an additional 2K. You would need to go out to 4-4.5L which wouldn’t fit. The Atlas engines were made before the vehicles they were put in. The H3 was designed around that engine to begin with, ditto the enclave/blazer.

        Reply
        1. Why do you think the power would be so limited? The Ram/Jeep Hurricane 3.0L twin turbo I6 is going to have 400 and 500 hp variants.

          Reply
          1. The hurricane runs very differently. It runs hotter turbos with more lag than GM’s, and at higher RPM’s. What you would be talking about is a turbo swap and compression ratio reduction. There’s no reason the 2.7 wouldn’t be able to make 700HP by bolting on a turbo from a freightliner. It would take almost 10 seconds to build boost and run at 7000RPM though.

            What the article talks about is modular cylinder count. The cylinder would be the same size, compression ratio and boost pressure. Therefore you would need additional displacement for more power with turbos tuned to similar RPM’s. That was the plan as it would keep costs down. Going to build a all new clean sheet engine would costs so much it ended up being better to make a new V8.

            Reply
            1. Remember that the hurricane 6 is based off the hurricane 1.5L 3 cylinder and 2L 4 cylinder engines. All share the same cylinders, connecting rods and head design. The 2L also makes 280HP. Almost as much as the much larger 2.7 turbo. It also is laggy, high reving, and guzzles gas when compared to the GM engines.

              Reply
            2. If you were to take the Stella plan, and take 2 GM 1.5L LSD turbo engines and bolt them together (175 HP, 203 for lbs,) you would get 350HP, and less torque than the 2.7. It still wouldn’t fit with those engines, but you wouldn’t be at the claimed 500HP. Tuning does matter and to keep the fuel consumption going to hell and turbo lag down, it would need to be about 4L

              Reply
            3. GM’s latest inline engines are following their Cylinder Set Strategy (CSS) design where each engine is optimized for its application. Other than the 2.7 and 3.0 Duramax, the 1.2L and 1.3L 3cyls were also designed following CSS. CSS does not use a specific set of components.

              Reply
        2. Everybody keeps talking about HP, that’s a measure of work done. torque is the worker. Without torque nothing moves, the higher the torque the better the performance.

          Reply
          1. No. Torque means nothing without rpm. Its all about horsepower. What you are actually referring to by “torque” is a higher amount of torque at lower rpm which results in more power at a lower rpm.

            Reply
            1. Correct, it’s HP @ your working RPM. Torque is nice so you can have HP @ a lower RPM and mossy along. You don’t want a too much torque down low and none up high either. The L3B has exceptional power down low, but when your merging with a trailer, it wheezes out and you’ll still be screaming at 5500RPM.

              Reply
              1. No, that’s what the higher gears are for, let it upshift and stay in the max torque range.

                Reply
                1. When you need 300+HP to go up a 13% incline with you trailer, or are merging on the freeway, you need to down shift not up shift. Your turbo engine will be screaming. That that point the folly of an engine with lots of low down torque but no high end torque becomes clear. You become a hazard as you drop to 45mph as your engine wheezes out.

                  If you upshift back into your torque band, your horsepower will only be 180HP as power = Torque X RPM, and you’ll come to a slog.

                  Reply
    3. I agree steve,whats up with this site,I clicked thumbs up,it went to 6 a few seconds later 0

      Reply
  3. The 2.7 is a joke and another GM idiotic decision. It gets less mpg than all the other engines.

    Reply
  4. A good friend of mine tows a huge boat (Twin Big Blocks) thousands of miles a year with a Tahoe. He is over 200,000 and hasn’t done anything except routine maintenance. He says he has many friends with the same experience. I seriously doubt these small turbocharged motors will hold up under that work.

    Reply
    1. You clearly haven’t tried L3B.

      Try it. Your doubts will be eased… and likely eradicated.

      Reply
      1. It’s built like a OTR diesel. Cummins/Detroit diesels blow turbos all the time. It does help though that class 8 trucks have a huge engine bay with a engine cover that tilts forward so the turbo is right there looking you in the face. Ecoboosts require you removing the cab to get to the turbos under the manifolds. These turbos will almost guarantee fail at or before 200,000K, but at least on the 2.7, there’s only 1 and you can reach it yourself.

        Reply
  5. Ofc they canned it. But let it be another weak ass 4 or 3 cylinder and they’re all for it 🤦🏾‍♂️

    Reply
    1. No, they decided to invest in the pushrod V8 instead. The smaller engines are needed for smaller models where a push rod V8 is not appropriate.

      Reply
  6. Boosted engines are like boosted people. Taking drugs seems like you have more power but in the end it’s a bad idea. Develop your basic self and develop the basic V8.

    Reply
  7. Ok now that GM has decided to cancel the TT I-6 gas engine, how about they get moving on filling orders with the LZ0? Especially with the max tow and in a double cab. I see GM is slowing or stopping production to keep pricing and profitability up. How about increasing production and flexibility so you can sell a truck? Eventually this strategy will lead folks to competitors where recovering lost market share will be far more difficult than if you would have just built the trucks and retained loyalty.

    Reply
  8. Really I mean nobody wants a 4 cylinder in a big truck doesn’tmake sense I had a tacoma with a 4 cylinder hard time making it up big hills

    Reply
  9. For Jim R, You are 100% correct. I left GM after 50 yrs all GM’s in my 6 car garage, Now 2 older GM trucks. & Chrys/Ram are in their place.

    Reply
    1. Tony, GM now has the top interior and the LZ0 is the best engine out there in a light duty diesel. GM needs three gear options. 3.23 (standard), 3.55 (needed) and the max tow 3.73 (rare as a unicorn). People want to tow with half tons where 900lb tongue weight on the standard final drive is just not enough. If GM is keeping the loads down by limiting tongue weight, then they need a 3.55 final drive option and more rear spring to get the job done.
      Trailers run from 10% to 15% tongue weight where the spring pack needs to reflect tongue weights higher than 10% GVW of the trailer.

      Reply
  10. Mistake. should build it, or they need something significantly better in the next gen v8s.

    Reply
  11. Only difference is the reliability of a straight 6 is Legendary and low end torque.

    Reply
  12. They never should have used the 4 cylinder for the Silverado. Or kept it for work trucks.

    The 4 cylinder is great for cars and SUVs. Colorado too since expectations are lower there. They should have launched a 6 cylinder in the Silverado from day one.

    I was excited to see a turbo 6 in the Silverado. Their next gen v8s needs to see a big power and fuel efficiency improvements now. Hopefully the mainstream V8 isn’t lethargic again because the reality is Ford has had two strong boosted v6s and a V8. Ford passing them on truck powertrains is just plain lazyness. Resting on your laurels when the competition keeps improving.

    Reply
    1. Ford blo-motors suck. They sound awful and economy is not there. Guys with these motors hang out on GM Authority and other GM forums and boast about their stupid tubro-Fords and bash the legendary GM small blocks. Lethargic? please. And Ford is not beat GM at anything.

      Wear your cap backwards and go do your Costco runs in your F150 like all the other posers.

      This is where Mr. Mike (who obviously has deep regrets for getting his Ford, calls everyone names for loving their 5.3s and 6.2s.

      Reply
      1. Low self esteem is not a good look for you.

        Reply
        1. Maybe you can wreck it and then get into a nice GM truck. I’m sure you’ve tried leaving the keys in it – but no one will steal the dang thing. Lord knows you can’t get out of your lease or high dollar loan – as you’re way upside down on the mortgage you’ve got on it. If you could only get out of it, you wouldn’t have to keep coming here to get out your passive regret-induced aggression.

          Reply
    2. Think the next generation V8 will only be the 6.2? They only need one good V8. I don’t see any reason the 5.3 should continue…

      Reply
  13. I noticed a lot of comments about the longevity of the V8 and the turbo powered 6 cylinders were left out. I am definitely a V8 fan and have a few but I went to the edge on a f150 3.5 several years ago and I’m sold now. Regular maintenance a nice aftermarket towing tune with an after market intercooler and there’s not a V8 gm has including the 6.2 that can tow with it. Let the war begin but this is 2023 and technology is much better. With that said I will also admit that the term Ecoboost is a joke. My company truck with the 5.0 can match everyday fuel economy empty and will get better towing but it will NOT tow as well as the 3.5. just my 2 cents, take care all.

    Reply
    1. Same here. I’ve had countless 5.3’s. The new ecoboost trucks are unlocked now too and gains of 125whp/125tq on a tune only, 93 octane. So that’s 550hp/650tq on a tune only vehicle. Don’t want to mod? The acceleration of the 3.5 already beats the Ram and any GM 1/2 ton. Did I mention I get 2-3 more mpg? I was sold on the 2.7 EB and couldn’t wait for my order any more and took an in transit 3.5 EB. The 2.7 was so much more punchy and fuel effecient than my 5.3’s were.

      I like the looks of the chev a tad more and their interiors are no longer the joke of the industry but they need more, including better engines to bring me back. There are always the blind fanboys to buy them though.

      Reply
  14. The other thing I would like to add to this conversation is the Ecoboost has now been out 12 years. You do not hear about turbo failures often or any other big issues. Ford designed that engine like a Diesel with direct injection and 2 turbos and then added cooling to the turbos with the oiling. To put this back in the GM court I will say being 55 years old I remember very well when GM produced a 3.8 v6 with a single turbo and then tuned it just a little and called it the GNX. To this day still one of my favorites, that was a BAD car! To bad it didn’t stick around longer but it tore the flagship V8 Corvette out it’s frame so it was stopped. The Camaro wasn’t even close with it’s big 350 tuned port injection. That was almost 40 years ago so fast forward to what Ford has done with technology and I will say until you have driven and tested one you are missing out. The are very fun to drive and pull like a mule for the weekend guy. If needed t pull a bunch I would buy the diesel, the V8 is losing it’s place with technology and I will miss that exhaust note but I won’t hear it much cause I will be in front of it, just saying…… Peace my brothers

    Reply
  15. This is exactly where I am. Ram is going to make a huge mistake getting rid of the 5.7 Hemi and will eliminate their otherwise excellent trucks off of many contention lists (including mine).

    It’s not about the “absolute HP number”, it’s about loafing along at 1500 RPM on the highway, with plenty of torque on tap.

    It’s about NOT waiting for some turbo to spool up to pass a car.

    It’s about hearing the rumble of the exhaust on acceleration, and the good engine sounds in the cab.

    All these components make up the driving experience.

    The Ford Ecoboost will set you back in the seat at 5000 RPM, but it sounds like a toy and for some of us revving it to the moon is anti-religion.

    GM made a good call here, sign me up for a Gen6 V8.

    Reply

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