Cateva detalii despre motoarele de Formula 1 2006–2011 For 2006, the engines had to be 90° V8 of 2.4 litres maximum capacity with a 98 mm maximum circular bore, which imply a 39.7 mm minimum stroke. They had to have two circular inlet and exhaust valves per cylinder, be normally aspirated and have a 95 kg (209 lb) minimum weight. The previous year's engines with a rev-limiter were permitted for 2006 and 2007 for teams who unable to acquire a V8 engine, with Scuderia Toro Rosso using a Cosworth V10, after Red Bull's takeover of the former Minardi team did not include the new engines. Pre-cooling air before it enters the cylinders, injection of any substance other than air and fuel into the cylinders, variable-geometry intake and exhaust systems, variable valve timing were forbidden. Each cylinder could have only one fuel injector and a single plug spark ignition. Separate starting devices were used to start engines in the pits and on the grid. The crankcase and cylinder block had to be made of cast or wrought aluminium alloys. The crankshaft and camshafts had to be made from an iron alloy, pistons from an aluminium alloy and valves from alloys based on iron, nickel, cobalt or titanium. These restrictions were in place to reduce development costs on the engines. The reduction in capacity was designed to give a power reduction of around 20% from the three litre engines, to reduce the increasing speeds of Formula One cars. However in many cases, performance of the car improved. In 2006 Toyota F1 announced an approximate 740 hp (552 kW) output at 19000 rpm for its new RVX-06 engine, but real figures are of course difficult to obtain. For 2007 the engine specification was frozen to keep development costs down. The engines which were used in the 2006 Japanese Grand Prix were used for the 2007 and 2008 seasons and they were limited to 19,000 rpm. In 2009 the limit was reduced to 18,000 rpm with each driver allowed to use a maximum of 8 engines over the season. Any driver needing an additional engine is penalised 10 places on the starting grid for the first race the engine is used. This increases the importance of reliability, although the effect is only seen towards the end of the season. Certain design changes intended to improve engine reliability may be carried out with permission from the FIA. This has led to some engine manufacturers, notably Ferrari and Mercedes, exploiting this ability by making design changes which not only improve reliability, but also boost engine power output as a side effect. As the Mercedes engine was proven to be the strongest, re-equalisations of engines were allowed by the FIA to allow other manufacturers to match the power. 2009 saw the exit of Honda from the Formula 1 racing series. The team was acquired by Ross Brawn, creating Brawn GP and the BGP 001. With the absence of the Honda engine, Brawn GP retrofitted the Mercedes engine to the BGP 001 chassis which resulted in a very successful season which saw the newly branded team win both the Constructors' Championship and the Drivers' Championship from more notable contenders, Ferrari, McLaren-Mercedes and Renault. 2010 saw the re-introduction of Cosworth to the grid; who had been absent since the 2006 season. New teams HRT and Virgin Racing along with the established Williams used this engine. The season also saw the withdrawal of the BMW and Toyota engines, as the car companies withdrew from Formula One due to the recession. 2014 The FIA has announced the intention to change the 2.4-litre V8 engines to 1.6 litre V6 turbo engines including energy recovery systems and containing fuel flow restrictions, in order to make Formula One more environmentally aware and to attract more commercial partners for 2014. The engines would also be limited to 15,000 rpm. In addition to the current suppliers, a new company, Propulsion Universelle et Recuperation d'Energie (PURE), has been founded to produce the 2014-specification engines. The new formula is set to reintroduce turbocharged engines, which last appeared in 1988, have their efficiency improved by turbo-compounding and introduce more energy recovery systems - with power to be harvested from the brakes and exhaust gases. The original proposal for four-cylinder turbocharged engines was not welcomed by the racing teams, in particular Ferrari. Adrian Newey stated during the 2011 European Grand Prix that the change to a V6 enables teams to carry the engine as a stressed member, whereas an inline 4 would have required a space frame. A compromise was reached to adopt V6 turbocharged engines instead.