Why dont the FIA do away with the reams of regulations they have generated from arguing with the teams for decades and just say,
"We will decide what is legal or not legal solely based on how we manipulate the racing and decide who is going to win".
Makes it much simpler to understand.
The differential on the redbull does the same job as any other differential.
It takes a torque input and 'vectors' that torque between two rear tyres.
It is a torque vectoring device.
A differential's purpose is to transfer torque to the tyres so as to maintain traction.
ANYTHING that 'actively' controls the input torque to an F1 differential is a traction control device.
The FIA cannot conveniently split the powertrain up to suit their regulations it makes NO engineering or scientific sense.
Kers does have a varying effect on the input torque to the differential but it is uncontrolled by default.
However, any 'active' and 'designed' method of using the Kers M/G to prevent or reduce the tyres breaking traction IS a form of traction control.
I realise the teams have problems preventing wheel lock up under braking which requires active control over Kers harvesting to balance rear end control on deceleration and gearshifting.
However this is because of the ' seamless' semi automatic layshaft gearboxes used and the lack of powertrain control they allow the driver.
It is almost impossible to balance the unloading of torque during the 'gap' when the trick shift mechanism in the gearbox actuates and at the same time harvest energy from the Kers M/G.
This forced the FIA to open up the programming in the ECU to control the problem.
The FIA established its own 'illegal' traction control by doing so.
Adrian Newey has simply exploited these regulations which have no real meaning or scientific base but leave a huge gap.
There are no ifs or buts about it, using the Kers M/G to prevent wheel spin is traction control.
Spirit of the regulations? Oh right!
I have known about this manipulation of Kers technology ever since it was first used.
I have waited to see just how far the technology would be exploited against that 'spirit'.