McLaren's Lewis Hamilton proved fastest in the first practice ahead of the Hungarian Grand Prix while Red Bull, hit by a controversial engine change, endured a slow session.Driving in warm, sunny conditions on the Hungaroring, Hamilton clocked a best time of 1min 22.821 followed by McLaren team mate Jenson Button and World championship leader Ferrari's Fernando Alonso.Red Bull's drivers failed to make it into the top 10. Mark Webber, second behind Alonso in the F1 championship, was 13th while Sebastian Vettel 15th.RED BULL SLOW DOWNRed Bull was forced to change their engine torque mapping after the governing International Automobile Federation closed a loophole in regulations.The new ruling limits how much teams can change the settings that control the amount of torque delivered by the engine in various conditions. Red Bull was referred to the stewards over engine torque mapping before the German GP but was cleared of a breach of regulations and the IAF made it clear in its wording of the decision that it was not happy with the situation.Vettel said: "It's not as if the car doesn't work any more. I'm quite confident nothing will change. There is probably more fuss outside the car than the difference is inside."Red Bull has a reputation for keeping a low profile in qualifying.The conditions in Budapest were a contrast to the wet build-ups to the previous two races at Silverstone and Hockenheim.Hamilton and Button have both praised the performance upgrades which McLaren introduced following a disappointing race at Silverstone.The Hungarian GP will be the 11th of the 20 races of 2012 and will be followed by a one-month break. Alonso is 34 points clear of Webber at the top and will lead into the break regardless of the outcome of the July 29 race. First practice session results ahead of the Hungarian Grand Prix in Budapest:1 Lewis Hamilton (Britain) McLaren 1min22.821 2 Jenson Button (Britain) McLaren 1min22.922 3 Fernando Alonso (Spain) Ferrari 1min23.397 4 Nico Rosberg (Germany) Mercedes 1min23.628 5 Romain Grosjean (France) Lotus 1min23.633 6 Michael Schumacher (Germany) Mercedes 1min23.845 7 Felipe Massa (Brazil) Ferrari 1min23.904 8 Kimi Raikkonen (Finland) Lotus 1min23.983 9 Valtteri Bottas (Finland) Williams 1min24.152 10 Sergio Perez (Mexico) Sauber 1min24.268 11 Pastor Maldonado (Venezuela) Williams 1min24.300 12 Kamui Kobayashi (Japan) Sauber 1min24.394 13 Mark Webber (Australia) Red Bull 1min24.546 14 Paul Di Resta (Britain) Force India 1min24.559 15 Sebastian Vettel (Germany) Red Bull 1min24.608 16 Daniel Ricciardo (Australia) Toro Rosso 1min25.354 17 Jean-Eric Vergne (France) Toro Rosso 1min25.559 18 Jules Bianchi (France) Force India 1min25.715 19 Vitaly Petrov (Russia) Caterham 1min26.440 20 Charles Pic (France) Marussia 1min26.705 21 Heikki Kovalainen (Finland) Caterham 1min26.755 22 Timo Glock (Germany) Marussia 1min27.015 23 Pedro de la Rosa (Spain) HRT 1min27.101 24 Dani Clos (Spain) HRT 1min28.17 Saturday qualifying (July 28) and Sunday’s race (July 29) will each start at 2pm SA time. Stay with Wheels24 for the 2012 Hungarian F1 weekend.