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Should GM Offer The Turbo 2.7L High-Output L3B Engine In The Full-Size SUVs?

Despite an industry-wide pivot to electric vehicles, internal-combustion engine technology continues to impress. That includes GM’s turbocharged 2.7L High-Output L3B four-cylinder gasoline engine, which can be found in a broad variety of applications, including the Chevy Silverado 1500, GMC Sierra 1500, Cadillac CT4, Chevy Colorado, and GMC Canyon. Notably, the turbo 2.7L I4 L3B is not offered in GM’s full-size SUVs – but maybe it should be.

Should GM offer the turbocharged 2.7L I4 L3B in its full-size SUVs?

Turbocharged 2.7L I4 L3B gasoline engine

While some readers out there will no doubt scoff at the idea of a modern, full-size GM SUV running a turbocharged four-banger, the spec sheet starts to bring things into focus. At present, GM’s full-sizers, including models like the Chevy Tahoe, Chevy Suburban, and GMC Yukon, offer three engine options – the naturally aspirated 5.3L V8 L84 gasoline engine, the naturally aspirated 6.2L V8 L87 gasoline engine, and the 3.0L I6 LM2 turbodiesel Duramax engine.

However, when it comes to peak torque numbers, the High-Output L3B nearly matches that of the L87 and LM2, churning out 430 pound-feet as compared to the 460 pound-feet produced by the L87 and LM2. And compared to the L84’s 383 pound-feet of torque, the L3B simply offers more peak twist.

L3B, L84, L87, LM2 Specs
Engine Type Turbo 2.7L I4 5.3L V8 6.2L V8 Turbodiesel 3.0L I6
RPO Code L3B L84 L87 LM2
Bore x Stroke (in / mm) 3.63 x 4.01 / 92.25 x 102 3.78 x 3.62 / 96 x 92 4.06 x 3.62 / 103.25 x 92 3.30 x 3.54 / 84 x 90
Block Material Cast aluminum Cast aluminum Cast aluminum Cast aluminum
Cylinder Head Material Cast aluminum Cast aluminum Cast aluminum Cast aluminum
Valvetrain DOHC, 4 valves per cylinder, VVT OHV, 2 valves per cylinder, VVT OHV, 2 valves per cylinder, VVT DOHC, 4 valves per cylinder
Fuel Delivery Direct high-pressure injection with AFM Direct high-pressure injection with DFM Direct high-pressure injection with DFM High-pressure common rail direct injection
Horsepower (hp / kw @ rpm) 310 / 231 @ 5,600 355 / 265 @ 5,600 420 / 313 @ 5,600 277 / 207 @ 3,750
Torque (lb-ft / Nm @ rpm) 430 / 583 @ 3,000 383 / 519 @ 4,100 460 / 623 @ 4,100 460 / 623 @ 1,500
Transmission Hydra-Matic 8-speed automatic Hydra-Matic 10-speed automatic Hydra-Matic 10-speed automatic Hydra-Matic 10-speed automatic

Interestingly, the L3B also offers peak torque at a lower rpm than the V8 engines, and more power than the diesel six-cylinder as well.

With all that in mind, the High-Output L3B isn’t really that much of a stretch for GM’s full-size SUVs. Of course, it might not be the best option for the more-refined Cadillac Escalade, but for the Chevy Tahoe, Chevy Suburban, and GMC Yukon, it could very well hold its own.

Then we have fuel economy. While we don’t know what sort of returns the L3B would provide in a full-size SUV, we can estimate, and based on the other gasoline engine ratings, the L3B could provide some pretty decent mpg figures. As a cherry on top, the L3B is actually 130 pounds lighter than the atmospheric 5.3L V8 L84.

Fuel Economy Estimates
Engine Drivetrain GMC Sierra 1500 GMC Yukon
L3B 2WD 19/22/20 18/21/19 (estimated)
L84 2WD 16/21/18 15/20/17
L87 4WD 15/19/17 14/18/16
LM2 2WD 24/29/26 21/27/23

So then, what do you think, dear reader? Should GM offer the turbocharged 2.7L I4 L3B gasoline engine in some of the automaker’s full-size SUV models? Let us know by voting in the poll below, and remember to subscribe to GM Authority for more GM technology news, GM business news, and around-the-clock GM news coverage.

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Jonathan is an automotive journalist based out of Southern California. He loves anything and everything on four wheels.

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Comments

  1. Actually shocked they are not offered already.

    I expect it is coming anyways. The coming numbers will force it.

    Reply
  2. Already available in the in full size Silverado. Torque is king. With 430 lb/ft. It will no doubt have no problem powering a Tahoe or Yukon. Revise the tune to bump up horsepower to 325- 330. The 2.0 Turbo in my wife’s Buick Regal has made a believer out of me on the smaller displacement Turbo engine.

    Reply
  3. A Suburban with four cylinders will SIT on the lots and be a laughingstock. Not sure if even heavy discounts would sell it.

    Guess it’s perception; a vehicle that size and price needs an engine to match.

    Reply
  4. Considering they sit on the lots so long for the Silverado. I would say absolutely not.

    Reply
  5. When the 4T came out in 18 and the lots were full of trucks you could not find a 4T, same answer we are not ordering any 4T,now gm tells them 4T truck or no truck.

    You may save a couple of MPG if you puppy it around town, highway no.

    I hope gm stays with the great deal of giving a $2000 “discount” for accepting a 4T.

    Reply
  6. Only if offered in a base L trim with vinyl bench seatingfor 9 and a 7000$ discount as a contractor vehicle. You have also got to understand that the fuel economy will tank as the 2.7 already rides into the turbo while cruising with the lighter Silverado. Fuel economy numbers will be even worse on the suburban. The 5.3 is a better fit for the suburban. I’d like to see the 2.7 on a traverse however. The 9l65 will need upgraded however.

    Got to remember that not even ford offered their 2.7 on the expedition. Engines that small were originally designed for fuel economy, and with the ecoboost coming out as being either eco or boost, there’s no advantage when your in a vehicle that’s just boost. There better be a good monitary incentive or people will just pay the extra grand to upgrade to the more capable engine.

    Reply
    1. The added weight (SUV are tested with weight simulated to near GVW), the part-load advantage of the small engine goes away. The 5.3 is CHEAP for GM to build.
      It would be awesome in the Traverse-

      Reply
    2. I like the idea of an L trim level Suburban. I grew up riding in an all black vinyl second hand former fire chief station wagon. Somehow, I made it even without the DVD, no XM stereo, no power windows, no A/C, no sunroof, no power locks, no driving nannies, no two tone leather, and (shock) rubber floors. And I still think my Dad was a very cool dude.

      Reply
  7. imma say no. imo it would be better in the traverse / blazer

    Reply
    1. Not sure it can go transverse and I don’t think the drive line can take the torque.

      Reply
      1. They once made a 6 speed AWD transaxle for the XTS V-Sport that could take the even more powerful 3.6 Turbo. But now everyone wants 8 or 10 gears for bragging rights.

        The XT4, 5, & 6 need this engine badly.

        Reply
        1. The XTS V-sport was limited to 369 lbs-ft – similarly, Ford limited their 3.5 Ecoboost vehicles to 350 lbs-ft in their cars that also used the GM-Ford 6-speed transverse transmission. A beefed up 9T65 probably wouldn’t get the full bore LB3 tune, but would still have a lot more torque than the 3.6L NA motors.

          Reply
          1. Even if the rating was around #70, it would be completely flat.

            Reply
      2. Excellent question. So they put the 2.0LTG in the traverse RS, which made a measly 260hp which pales next to the V6, and the 2.7 L3B is actually a stroker engine with a longer stroke, smaller bore. The bore of the LTG is 86mm, the L3B is 92mm. We’re talking about a little less than 2 inches. Also, they fit a 5.3 into the impala SS in 2007, and it’s bore is also 92mm. As for the transmission, the 9T65 was capable of taking the 300ftlbs from the 2.0 turbo. Definitely not the full 430 ftlbs, but with slight modifications, the original 380ftlbs might be possible.

        Reply
  8. NO! Increase production of the 6.2 V8.

    Reply
  9. I expect the lighter trucks to lose the V8 at some point and may only be 4 or 6 cylinders.

    The V8 can easily live in the larger 3/4 and one ton trucks as regulations are easier on them.

    This is what a GM engineer stated a while back. I just did not know if those plans were in play. With the new V8 they may be.

    Reply
  10. It needs to replace every 3.6 application for sure but what what full-size SUVs need more is a hybrid system.

    Reply
  11. Great idea, Ford has popularized the turbo 4’s and 6’s across their truck lines with great success. I have a 22 Ranger and it smokes my friends Colorado in all categories, this 2.7 engine sounds like a real winner, we all hope it’s reliable.

    Reply
  12. I noticed the charts do not provide fuel economy. If there are not much MPG savings then I would rather stay with the proven V8s engines.

    Reply
  13. The L3B should cost a lot less to produce than any V-style engine. Count the sub assemblies: 1 head, 1 exhaust, 4 pistons, and all the associated parts. There is an additional camshaft and the turbo. This engine will package a lot better in a front drive vehicle. I think GM will slot all its EV’s at higher prices than Gas Vehicles, and thrift out the lower priced gas vehicles until they completely go away.

    Reply
  14. Talk about the “dog” of the lineup. This is a movie we’ve already seen, with GM’s full-sized 1500 pickups.
    Instead of investing in something that really matters, such as–oh, I don’t know–a good interior, GM went all-out designing a four-cylinder engine that powers like a V-8, torques like a V-8, and tows like a V-8.
    So what’s not to like? Oh, yeah: This whiz-bang turbo four-cylinder engine still feels like a four and sounds like a four. It’s coarse and shrill, in other words. It turns out, moreover, that the same technology that makes this turbo-four such a powerhouse (at least on paper) is somewhat fragile. For that reason, this precious little engine is prone to breaking down as the miles build up.
    The crowning insult? It turns out that real-world fuel efficiency–surely the raison d’etre for designing such an exotic little engine in the first place–is no better than that of the V-8s this turbo-four is intended to replace. Purpose: defeated.

    Reply
  15. For mama to drop off the kids and get groceries in her $80k Tahoe, 90% of owners will never even know what’s under the hood.

    Reply
  16. GM should Learn from Porsche and their move to 4 banger in the Boxster. Power is good but the truck will sound like a Singer Sewing Machine going down the road . . . . . . . . . . .just sayin.

    Reply
    1. Boxer 4’s don’t package well. Their flat, but that makes them insanely wide and their still not very short as the manifolds have to stretch to opposite ends of the engine. Boxer 4’s are for lowering the center of gravity, not packing efficiency, lower weight or power.

      Reply
    2. Porsche is moving back to flat sixes in the 718 lineup. At least in the GTS & GT4 models.
      Also, I had 3 Subie STI’s in the past and I sold them all before or after 60,000 miles. I never trusted the turbo charged engine to last much longer without major turbo repair costs. I experienced one turbo issue in one of the STI’s, a 2010 model that had 29,000 miles on it at the time but out of warranty by 4 months. Luckily Subaru picked up the +$4,000 repair charge as an act of good faith. Would you feel confident that gm would do so for a Suburban in a similar situation?
      If I had to chose an engine for a Suburban it would be the diesel, and yes I am aware that it would be contrary to my first statement about turbos.

      Reply
  17. If they can’t design a good shifting transmission, what good is any motor!!!

    Reply
  18. NO! NEVER! BAD IDEA! Remember when Traverse offered a 2.0T? It was salesproof!

    Reply
  19. Very few want this for an engine in the larger vehicles. It’s a deal killer for many in the GM driving public.

    Reply
  20. I wonder if this high output turbo four will need premium gas for the highest output.

    Reply
  21. Not for me! Maybe in a2,000 lb. Car or small truck , but then your in a death trap!! Turbo are for kids!! & a lot more maintenance! V/8 Baby !!

    Reply
  22. I have driven a turbo 4 in a 2021 Cadillac CT4, given to me as a loaner, and it was a real dog in that compact car. It got worse gas mileage than my Corvette and sounded like it was going to send a rod through the bottom any second. A 60 mile one-way trip from the dealership to home and the thing drank 1/4 tank of gas. On the interstate it could ALMOST get out of its own way. I can’t imagine the repairs on this thing!

    That POS needs to be kept in China.

    Reply
  23. Absolutely not. Small gasoline engine with high output made of aluminum will have a disappointing short life.
    These engines are designed to meet Federal fleet fuel standards with designed obsolescence of less than 200K miles. GM wants car owners to turn their vehicles every 2 to at the max 5 years. It’s a designed cycle program. Industrial grade in the automotive industry is gone. It went out with the elimination of the gray iron engine.

    Reply
    1. GM is IMHO, actually the best at making vehicles last and repairable by DIYers. I’d bet they’d love to pull a fiat and have their buyers right back at the dealership 18 months later for a new vehicle, but they know the moment that happens they’d loose business even new GM’s have more engine bay space for repairs, the 5.3 is a 500K engine if cared for and the 3.6 is a 300K now that the timing chain issue is resolved and they’ve added an extra quart of oil.

      Even this 2.7 turbo is going to be more reliable than fords. It’s got a pedigree from the original eco tech motor which is a 250K motor easily, and while to turbo will likely need replaced at 150K, at least you can reach it from the engine bay and do t have to remove the whole cab like the ford.

      Reply
  24. They should put the current HD engine, transmission and suspension in the Suburban like they did up until 2019. Some people use the truck for towing and hauling. But I suspect the next HD Suburban will get the EV treatment instead.

    Reply
  25. I learned from a Ford engineer at the SEMA show a couple of years ago that FoMoCo has a German vendor design their small gasoline high output engines. Makes sense to me since German carmakers originated this small displacement turboed high output popular throw-a-way engine.

    Don’t expect to get beyond 200K miles.

    Reply
  26. The 2.7 Turbo requires using PREMIUM unleaded gas at 40 cents a gallon more! Where’s the saving in cost of operation?

    Reply
  27. Absolutely not.

    Reply
  28. They tried to push a 4 in the CT6. Didn’t work out well. Maybe for China. With the “transition”, pretty soon it’s take it or leave it.

    Reply
  29. Maybe as a rental fleet special.

    Reply
  30. I just would like to know who would buy one?

    Reply
  31. Should be out in the full size van.
    Chevy express with an economical engine would be a shop vehicle dream.

    Reply
  32. No way!!!!! Now a twin turbo V6 would be the way to go if you don’t want the 3.0 diesel.

    Reply
  33. Here’s a better one for you. If your so proud of the 4 cylinder put it in the new Corvette and see how well they sell and then get back to us M

    Reply
  34. If it was an I-6 I would say yes. GM was supposed to have a 6 cylinder version of this engine, but where is it? Have not heard any news on that in a long time.

    Reply
  35. To be honest the 2.7 would be more reliable if it was an OHV and barely not that much more powerful than a duel OHC. engine ! all gm engines need to go back to OHV and eliminate Afm – this trying to save % .002 mpg is absolutely nonsense and the cost is only past on to the consumer !

    Reply
  36. I’ll pay $3k for the L3B to be an option on Buick Encore Gx (call it Encore GT) , and Envision. Subcompact and compact SUV’s need more than those tiny 1.3-1.5L one size fits all.

    Reply
  37. Geez! I wish this engine would be available in subcompact and compact SUV’s. Put it as the $5 k option in the Buick Encore GX. Change the anemic 1.3L turbo, 155 ho with a meatier 2.7L, 410 hp version. I’d jump on that!

    Reply
  38. No!
    I want a full-size SUV like a Tahoe or Yukon with a V6 / 3.6-twin-turbo / 472HP/ LF4 engine.
    The same goes for Silverado.
    Only use the 2.7 turbo 310HP L3B in Colorado or Canyon or Traverse.

    Reply
  39. The only reason this motor exists is to have a cheaper sticker price on a basic model. Period. If you’re burning the same amount of gas (MPG) then you’re putting out the same amount of exhaust. Only a fool would buy the 2.7L in a full size truck. Turbos have a failed history and track record and don’t get me started on aluminum heads and blocks.

    Reply

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