Clues say Tesla's secret "D" stands for dual-motor, all-wheel-drive Model S

Spy shot from Tesla Forums user adelman; Paris Motor Show press guide
Spy shot from Tesla Forums user adelman; Paris Motor Show press guide

Tesla Motors has such an intensity of following from its owners and fans that little can stay secret for long. So when co-founder and CEO Elon Musk tweeted earlier this week about a surprise announcement set for Oct. 9 involving the letter "D," it was bound to come out well before then. Today, we already have the likely answer: an all-wheel-drive variation of the Model S.

Musk's tweet was accompanied by a dim outline of the front of the Model S, but no other information. The first clue came, strangely enough, from the press guide of the Paris Motor Show, where Tesla was listed as revealing an all-wheel-drive Model S. That was a bit strange, since Tesla had no press conference on the schedule and no executives granting interviews — but it wouldn't be the first time a press guide had an error.

The second piece of the puzzle came from this photo snapped by a Tesla Forums user, whose friend had seen the car charging at an airport. The trunk lid of the Model S includes the designation P85D — with P85 standing for an 85-kWh Performance model; the D had not been seen before.

The D likely stands for "dual motor;" the Model S routes its power through a single huge electric motor on the rear axle, and for the upcoming Model X SUV, Tesla vowed to develop an all-wheel-drive system by adding a motor on the front axle. Since the S and X share a platform, adding it to the sedan would be a no-brainer.

Tesla spokesman Simon Sproule said that "all would be revealed next week." Having an all-wheel-drive variant brings Tesla up to par with other luxury automakers ' sedans, although we still don't know many other details such as price, performance and how the additional motor affects driving range. Musk promised "something else" in his message beyond the letter D; we'll see how long that stays secret as well.