He says: 'The two major technologies - the F-duct and the blown diffuser - we are still not completely there with.

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Mercedes had arrived at their home race in Hockenheim with a modification to their exhaust blown diffuser and a new rear wing.

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His driving style was not suited to the off-throttle blown diffuser, which Vettel used to such devastating effect en route to 11 wins in a truly dominant season.

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Ferrari have brought a new front wing to Germany, which is designed to work in tandem with the exhaust-blown diffuser they introduced at the European Grand Prix in Valencia a month ago.

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At Valencia the team's new blown diffuser was introduced and two weeks later at Silverstone came a totally new front wing - the one that was causing such suspicion at Hockenheim.

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"If you don't have aerodynamic features - like the F-duct or the exhaust blown diffuser - then you want to implement them, so you develop them at home, build them on to the car and test them on the race weekend, " explained Schumacher, who was used to unlimited testing in his previous Formula 1 career.

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