Tesla Model S owners claim P85D hp rating is exaggerated

A group claims the combined output is nearly 150 hp below Tesla\'s own estimate.

A few Tesla Model S owners have cried foul over alleged horsepower exaggeration for dual-motor variants such as the P85D.

"The P85D was marketed as making 691 horsepower. It doesn't," the letter claims, according to excerpts posted on HybridCars. "We believe, based on various testing methods and tools including dynamometer testing and testing with professional performance data loggers that the maximum energy output is 415 [kilowatts], which results in a maximum horsepower of 557 ... Even without factoring in drive train loss, this is almost 20 percent less than the advertised horsepower."

Following the complaints, Tesla published a blog post clarifying its methodology for estimating "equivalent" horsepower ratings for its dual-motor vehicles. The company "took the straightforward and consistent approach" of specifying the combined capability of both electric motors front + back.

"With the shaft horsepower coming out of the motors the situation is not always as simple as front + rear," wrote Tesla CTO JB Straubel. "As we have pushed the combined motor horsepower higher and higher, the amount of times where the battery chemical horsepower is lower than the combined motor horsepower has increased."

The executive suggests the discrepancy is rarely experienced in the 85D and 70D, as the combined motor shaft power almost always stays within a range that can be supported by the battery. The shaft power of the P85D's motors, however, "often exceeds the battery electrical horsepower available."

The company quietly changed its website to specify horsepower ratings for the individual motors -- 259 hp front and 503 hp rear in the case of the P85D. The combined total is no longer listed and, interestingly, the basic "front + rear" methodology described by Straubel results in an even higher total of 762 ponies.

"The missing horsepower is quite noticeable at highway passing speeds," the disgruntled owners added. "For example, from 70-90 mph ... the P85D is easily outperformed by an Audi RS7."

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