LONDON, March 25 (Reuters) - Most of the engine problems suffered by Renault-powered cars at the season-opening Australian Formula One Grand Prix have been resolved, the manufacturer said on Tuesday ahead of this weekend's race in Malaysia.
Renault supply world champions Red Bull, their sister team Toro Rosso, Lotus and Caterham with the new V6 turbocharged power units.
Of the four teams, only Toro Rosso scored points in Melbourne with Red Bull's world champion Sebastian Vettel retiring after a handful of laps and his Australian team mate Daniel Ricciardo disqualified from second place for excessive fuel flow.
Neither of the Lotus or Caterham drivers lasted long enough to see the chequered flag.
Renault Sport F1 track operations head Remi Taffin said in a preview for Sunday's race at Sepang that the manufacturer was optimistic of a better showing two weeks on.
"We had several issues across the cars in Melbourne but we have recreated the problems in the dyno at Viry (the factory in France). Most are fixed and the remaining (ones) will be under control by Friday in Sepang," the Frenchman said.
"While we anticipate further issues may occur we are much more able to react quickly to minimize their impact."
Taffin cautioned however that Sepang would be far tougher on the new engines than it had been on the old V8s that were pensioned off last season.
"In the V8 era the circuit sat towards the middle of the table for the challenge it posed for engines but now it will be one of the toughest races of the year," he said.
"The humidity in Sepang made it a little bit easier on normally aspirated engines since power comes down as the water content in the air increases. This means we were generally able to offset the impact of the two long straights. This year we won't have this luxury.
"With a turbo engine the air intake is controlled at all times regardless of ambient conditions so those long straights will really start to hurt," added the engineer.
The straights at Sepang are both more than 1 km long and will see the turbo revving at close to 100,000rpm for more than 10 seconds on each. Pressures within the combustion changer are almost twice as great as the V8.
High air temperatures also make choosing the right cooling level crucial. (Reporting by Alan Baldwin, editing by Ed Osmond)