There's a couple things different here. There is no SAE horsepower rating procedure for EVs yet (they are working on it, I mentioned the SAE number somewhere in this thread but too lazy to dig it up). Tesla never claimed they have an SAE rating (because nobody does), they very carefully described the number as "motor power", and now in response to concerns raised in this thread, they even removed the reference to 691hp.
About the Rx8, I don't believe there was ever a lawsuit over horsepower (although there were for other engine defects). The buyback and coupon offer for horsepower is mainly to quell the backlash over the issue (it wasn't selling well in the first place, so this would just be another nail in the coffin). Officially Mazda said the lower chassis dyno results may be from ECU pulling back on detecting abnormal conditions and some late tuning they had to do related to catalytic converter longevity.
The ECU pulling back can be the same issue in the dyno tests of the P85D so far. Otherwise I don't see a very good reason why so far the results are *less* than what the P85 was measured at, esp given the REST numbers are far higher. Someone who pulls REST at the same time as a dyno run may be able to answer some questions there.
There was a lawsuit but it did not go to trail. It settled out of court.
REST numbers were not taken with the two P85D dyno runs so we don't know what the car claimed it was pulling from the battery. It could have been too warm, or too cold. Who knows. Clearly the P85D under optimal conditions should dyno more than a P85 but the two that have been done so far are right around P85 numbers.
At any rate, the highest REST number ever obtained from a P85D is 414 KW which means that the most the P85D could ever produce with 414KW is 555 hp. But of course that assumes 0 loss through the inverter and through the motor. We don't know what those losses are. So the P85D is producing less than 555 hp under optimal 90% SOC with a warm but not too warm battery.
The SAE standards obviously don't apply to electric vehicle power testing, but 745.7 watts is still = to 1 hp no matter how you slice it. The REST numbers simply put an upper end on what the P85D could theoretically be making. It cannot make more than 555 hp under 100% zero loss conditions and it's probably making a lot less by the time it hits the motor shaft. I stress motor shaft because it's the most apples to apples comparison with the driveshaft of an ICE.
That said, we can give Tesla some discounts that make one of it's peak hp much better than an ICE's peak hp.
1) Instant response. No downshifting. No waiting for extra fuel and air to make it in response to the ECU telling the throttle body(s) to open open.
2) All wheel drive efficiency. The P85D doesn't have the same inefficiencies normally associated with AWD cars. AWD ICE cars have to transfer their mechanical energy through much more linkage and mass. Transmission, flywheel, transfer case, half shafts, etc non of which the P85D has. An AWD ICE car typically has 20 to 25% drivetrain loss loss. The P85D should be much less.
3) Width of power band. The Tesla produces it's power flat such that once you hit peak it mostly stays there. ICE cars have narrow peak power points such that the job of the transmission is to put gears just before and after the peak keeping you as close top the peak as possible. This is why the Tesla is so much faster from a stop. If you graph the power curve and integrate the area under the curve, the Tesla puts down much more power for the same peak power than an ICE does. This is why a P85D with 500 something real hp at the motor shaft will always kill an ICE from 0 to 60 as long as you're not slipping the clutch and relying on kinetic energy spooled up in a flywheel. Computer controlled versions of this are called launch control and even then it's hit and miss only working a fraction of the time. The P85D is pretty much a 100% consistent ride. I was stunned how my VBOX readings at 77 % to 74% produces such consistent 3.2 0-60 times within a 100 ms.
These factors make an AWD electric car with X hp much better, faster, and responsive than an ICE car with the same rated X hp.
It's just a darn shame that Tesla overrated the P85D by so much.
Note, I'm still hopeful they'll fix this. They're still telling customers when the ask directly that it's 691 hp. That's more likely because the CS reps haven't received instructions on telling customers anything different. I'm sure this issue is being taken extremely seriously and I'm hopeful they'll fix this.
There are those that are trying to claim Tesla didn't lie because the motor power of the two motors added up = 691 and nowhere did Tesla state that they'd produce that power together at one point in time.
TESLA IS NOT MAKING THIS STATEMENT THEMSELVES. This is speculation by other members. And if it's not what Tesla intended, it doesn't mean they lied. It just might mean they made a mistake or they got ahead of themselves and advertised something they intended to deliver but haven't quite yet.
I seriously doubt they'll try and fallback on word games as others have. When they advertised 691 hp, customers expect that the car will perform like a car that actually has 691 hp and in certain important ways, the P85D doesn't. It cannot accelerate as fast from a rolling start as cars that have even a much lower power to weight ratio spec. Tesla has a claimed weight to power ratio in the 7:1 range yet it performs like other ICE cars that have a ratio of 9:1 when comparing 50-70 and 70-90 passing.
