Note the 2.6s number is for 0-100kmh. 0-60mph is 2.5, which I believe is the 'standard' Ludicrous number, which the parameters of this vehicle profile aim to model. Of course, there is a limit to how accurate a simple model such as this, with only a few dozen parameters, can model an entire vehicle performance!
But the beauty of having a model is that you can change the model parameters to see what it would require to get a model S to 60 in 2.3s, and thus discover exactly what Tesla are doing.
Note that I've had to assume quite high friction values (mu=1.25) even to get to 2.5s number.
So assuming the tyres haven't changed and we are wheel slip limited in the 0-30 range, it would imply Tesla are raising the base speed somehow to extend the flat torque range higher to improve the 30-60 number.
Of course this another way of saying, they are increasing the motor peak max power. The 2.3s number could be achieved by upping the total motor power from 600kW to 700kW, but this pushes the max current from 1600A to ~2000A. This sounds astronomical, but given some of JB Straubels comments regarding their inverter, may not be so far fetched...
The power rating increases are largely enabled by better and better power electronics – transistors or IGBTs which is what we are using. As those improve, we can continue pushing up the current rating and continue increasing performance. If we can make the inverter just half a percent more efficient, that’s half a percent less battery pack that we have to put in the car or half a percent more range that the customer gets to have so it a very strong and virtuous feedback cycle with high efficiency.
And, this could be done within the 10C discharge envelope of the pack.
OTOH if the tyres can
achieve mu=1.6, that would pretty much do it...