I have searched the TMC forum for answers on this subject, and while I have mentioned this concern on several work orders, I have never gotten a satisfactory explanation or resolution. Here is the issue: I purchased a Signature 85, its serial S2108 for Canada - so early days. I got used to being able to carefully drive pretty close to the average of the 'rated range' line of the trip graph, in Si units: under 200Wh/km, often far less. Then my drive unit was replaced about a year ago - and ever since - my efficiency tanked. The drive unit was 'upgraded' to a P85 motor, as I was told the early S85 motors in the lower HP range were discontinued. Now I can no longer come close to the 200Wh/km number, and since the new drive unit was installed, I have gotten an average of 220Wh/km (equal to 354Wh/mi over 37,600miles) - which is on the high end I understand from reading the lifetime efficiency thread, and I live in a very flat area with moderate continental temperatures. On speaking with other Signature P85 owners that travel the same routes I do - we have shared stats, and mine are always higher - and this is less related to driving style, because we are often stuck in the same weekend traffic. So I was determined to get to the bottom of this. Last time I was in for service, the loaner was a P85 with the same wheels I have, same everything, just a newer car. I drove it home like a bit of an animal, lots of fast starts, I was trying to get a high number like with my sig - not even possible. My 71km trip consumed a total of 13.8kWh, for an average of 192Wh/km. the next night, almost identical empty road, same 22degree temperature, I drove like a little old lady in my car, and used 16.4kWh or 229Wh/km. A good 15% difference. And 15% of a 400km trip - as you all know, is the difference between arriving at your planned destination or not. Loaner P85 My P85 I would like to understand what the issue could be here. a) driving habits - I ruled this out after I did my test with the loaner. b) temperatures - same - ruled out after loaner test. c) wind and hills - ruled out. d) roof rack/sunroof/windows - nope. e) drag in wheel bearings - Tesla service checked - nope - rolls normally f) tire inflation/type/wheel type - same tires, same inflation (checked w. pocket guage, 42psi & 42psi) g) inversion issue - maybe h) regen issue - maybe At first Tesla said it was because the motor was a higher wattage model, but W=v*a, so if I am not *making* the motor work harder, why would it use more than the current supplied - it didn't make sense. I am starting to think my inverter is not paired to the new motor - could that be the issue? Where would the lost power go? Heat? Is my inverter getting unusually hot? I have no idea. I would be very grateful for any of you technically savante owners to offer your enlightened opinion here, as I am flummoxed to say the least, and I would like my car to perform as specified - and to do so, it seems I need to explain to Tesla what is in fact going on here. Thanks all!