Technology

The GMC Hummer EV’s 11,500 lb-ft torque number is misleading, here’s why – Roadshow

GMC’s Hummer EV will likely be highly effective, however doubtless not that highly effective.


GMC

The GMC Hummer EV will not formally launch till fall 2021, however it’s already throwing down some spectacular numbers — most notably, 1,000 horsepower and a whopping 11,500 pound-feet of torque. Factor is, that second quantity is not essentially an correct illustration.

All of it comes all the way down to what specification you employ. GMC’s large quantity seems to correspond to wheel torque, which is conventional motor torque multiplied via the transmission’s drive ratio. Jason Fenske from Engineering Defined has a great video that spells out the difference, a chunk he printed following Tesla’s declare that the Roadster 2.0 will produce greater than 7,000 lb-ft of torque. Fenske used a Dodge Challenger SRT Demon for instance. That mannequin produces 972 Newton-meters of engine torque (770 lb-ft). Nevertheless, multiplied via its gear ratios, you get 14,000 Nm of wheel torque (10,325 lb-ft) in first gear.

“Most EVs have a closing drive discount ratio of about 8:1 (Tesla Mannequin X is 8.28:1, for instance),” Sam Abuelsamid, principal analyst at Navigant Research, informed me. “With 11,500 lb-ft and eight:1, that might translate to motor torque of a bit over 1,400 lb-ft, which sounds proper with 1,000 hp. [Chevy’s] Bolt has a closing drive of seven.05:1, whereas [Tesla’s] Mannequin three is 9:1, so 8:1 is an inexpensive guess till we all know extra in regards to the Hummer.”

After I requested a GMC spokesperson to make clear, I used to be merely informed the ultimate, SAE-specific quantity could be launched nearer to the truck’s on-sale date, and that the 11,500 lb-ft spec is what the corporate is sticking with for now. GMC additionally stated the Hummer EV will be capable to speed up to 60 mph in three seconds. The truck will likely be produced at Basic Motors’ Detroit-Hamtramck plant, which is being retooled to only produce electric vehicles.

I not too long ago skilled this torque disparity firsthand. While testing an electric BMW prototype in Germany final summer time, an engineer informed me the modified 5 Series sedan was producing “round 10,000 Nm on the axles,” which equates to 7,357 lb-ft. Then I requested a unique engineer for the precise torque coming from the electrical motors, and was informed “1,150 Nm,” a still-not-insubstantial 848 lb-ft.

Sadly, there is not any direct conversion for these two torque figures, so it is exhausting to say with any certainty how a lot energy the manufacturing Hummer EV will provide. My finest guess is that it will nonetheless be a fairly large quantity — greater than 1,000 lb-ft, almost certainly — however nothing in five-digit territory.

When the Hummer EV goes on sale, it will compete with quite a lot of different still-in-development electrical vehicles
, none of which declare a torque determine as excessive as GMC’s. Tesla is estimating a fair 1,000 lb-ft for its Cybertruck, Bollinger quotes 668 lb-ft for its B2 (which appears a bit like an previous Hummer H1, coincidentally) and Rivian says the R1T may have 829 lb-ft.

The issue right here is not that the 11,500 quantity is inaccurate, it is simply very deceptive (however hey, a giant quantity looks better in a commercial). After all, there’s at all times the skin risk the truck will even have 11,500 lb-ft of torque, however I am not holding my breath. Both approach, I am fairly stoked to see what’s in retailer for this reborn, electrical Hummer. 

Initially printed Jan. 30.

#GMC #Hummer #EVs #lbft #torque #quantity #deceptive #heres #Roadshow

Author

Steven Ewing