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.
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.
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.
|Configuration||Twin-Turbo V6||Twin-Turbo V6||Twin-Turbo V6||Twin-Turbo V6||Twin-Turbo V6||Twin-Turbo V6|
|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.
|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|
|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|
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.