What Does GM's Trio of Ultium Motors Reveal For its Future Vehicles?
By Edward A. Sanchez – Sept. 23, 2021
The slow-drip of information regarding GM’s Ultium EV platform continues, with GM president Mark Reuss revealing a trio of modular Ultium-family motors designed to power everything from midsize crossovers to 1,000-horsepower supertrucks, including the forthcoming GMC Hummer EV.
Two of the motors are designed as primary motors, and one designed to be a supplemental rear motor in an e-AWD setup. The two main motors are a 180 kW (241 hp) unit intended primarily for front-wheel-drive applications, a 255 kW (342 hp) designed for rear-wheel-drive and truck and SUV applications (including the aforementioned Hummer), and a 62 kW (83 hp) motor envisioned as a supplemental rear axle AWD motor, presumably in conjunction with the 180 kW front motor.
GM also claims its power electronics controlling the motors are up to 50% lighter and more compact that current equivalents.
GM claims its forthcoming electronic control units will be up to 50% lighter than previous units and pack in 25% more capability.
Known and Potential Applications
We already know at least two applications for these motors, one being the GMC Hummer EV and the other being the Cadillac Lyriq, which was revealed to have approximately 340 horsepower in rear-drive form in April 2021. Combining the 180 kW front motor with the 255 kW rear motor would yield a combined horsepower rating of approximately 580 horsepower. That level of power would also make sense for a Camaro, or whatever its eventual successor will be, as well as another premium sedan – or for that matter, the Silverado EV.
GM’s big 255 kW Ultium motor is a 342 hp powerhouse that will likely help the Hummer EV produce its 1,000 hp.
The Ford F-150 Lightning long-range has already been announced as having 563 hp and 775 lb-ft of torque. We know the GM’s 255 kW motor is rated at 440 Nm (325 lb-ft) of torque. Doubling up the 255 kW motors would yield approximately 680 hp and 650 lb-ft of torque. So while the Silverado in such a configuration would come slightly short of the Lightning’s torque output, it would have a 100 hp advantage. Of course, effective torque can be manipulated by gear reduction ratio.
Although the idea of an electric Corvette may seem premature and borderline heretical before we even have the official reveal of the output figures of the Z06 and its DOHC 5.5L flat-plane V-8, you can bet a fully battery electric Corvette is on the drawing board, and possibly currently testing in prototype stage.
GM says it’s targeting its mid-grade 180 kW (241 hp) motor to power the front wheels of some of its future EVs.
The big issue in performance vehicles like the Corvette is weight, and the heaviest component in fully electric powertrains is the battery, and will probably remain so for the foreseeable future.
Although comparing a Corvette with the Hummer EV may sound like an apples-and-oranges comparison, the Hummer’s 9,000-pound weight does not bode well for a 1,000 hp Ultium passenger car. Even the Tesla Model S Plaid, the closest comparison point for a 1,000 hp performance car, weighs in at 4,766 pounds.
Coming in as an AWD assist, GM’s 62 kW (83 hp) motor could find its way onto numerous rear EV axles.
Bringing a fully battery electric Corvette to market with a weight under 4,500 pounds may be a challenge. A fully electric Corvette that comes in under 4,000 pounds would be a monumental feat of engineering. For that, you need to look no further than the 70 kWh Lotus Evija, which cracked the two-ton mark with a weight of “just” 3,700 pounds. To get there, though, the company had to presumably utilize numerous exotic weight-saving techniques and sells the car for more than $2 million.
There is no “one-size-fits-all” approach to electrification. GM’s modular approach to electric motors will help it make the transition to an eventual majority-BEV lineup easier. We look forward in seeing the next chapter in the Ultium story.
(Images courtesy GM)
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