In an open letter to Tesla Motors CEO Elon Musk, the group on TeslaMotorsClub.com claims the P85D “falls considerably short” of that 691 horsepower figure. Based on their dynamometer testing, they claim the real-world output of the dual-motor P85D is actually closer to 557 horsepower, and have appealed to Tesla regarding the alleged discrepancies and possible solutions.
On September 21, JB Straubel, Tesla Motors’ chief technical officer, published a note on the company’s website that didn’t explicitly respond to the open letter, but nevertheless clarified how Tesla assigns horsepower figures to its dual-motor, all-wheel-drive vehicles. Essentially, Tesla adds the horsepower rating of both front and rear motors.
The post also went on to discuss the difficulties of comparing internal combustion engines with electric motors, and also touched on environment effects, such as cold temperatures, which may fluctuate an EV’s horsepower.
“Since the battery electric horsepower rating varies it is not a precise number to use for specifying the physical capability of an EV,” wrote Straubel, “The motor shaft horsepower, when operating alone, is a more consistent rating. In fact, it is only this (single or combined) motor shaft horsepower rating that is legally required to be posted in the European Union.”
He concluded by adding, “The true measures for any performance EV driver are acceleration times and driving performance of the vehicle.”
While that might not be the response that the Tesla owners who penned the letter had in mind, it may be the only answer they’ll find.