Mat Coch writes:

Lotus will not run its controversial 'device' for rest of the Japanese Grand Prix weekend, the team has confirmed. Fitted to Kimi Raikkonen's car on Friday, which had a KERS battery problem in the afternoon session, the team was unable to calibrate its wing stalling device.

Debuted during practice in Germany the 'device' is understood to stall the airflow over the rear wing in a similar fashion to what became known as F-Ducts in 2010.

Where Lotus' 'device' differs is that it's believed to rely on air pressure to activate, whereby McLaren's system used driver movement. Such movement for aerodynamic benefit was banned at the end of the 2010 season.

Lotus design, in theory, means the system is always available. Once the air reaches a certain pressure, which is related to the speed of the car, a fluidity switch would be triggered to activate it. This is in contrast to Mercedes front wing stalling device which is only active when DRS is enabled.

"We suffered a disrupted day with Kimi's car but despite that we've achieved a reasonable amount," said Technical Director James Allison on Friday. "We evaluated 'the device' in the morning but were unable to make it switch effectively so we won't be using it for the rest of the weekend."

The Japanese Grand Prix is the third event the team has tested the device after Germany and Hungary. The squad opted not to run it in Belgium, Italy or Singapore.