Red Bull calm on Vettel's engine limit

Vettel suffered two engine failures at Valencia, leaving him with just two fresh power plants and two units that already have mileage remaining on them to last the rest of the season.

Drivers calling any additional engines into play will be hit with a 10-place grid penalty at the first event they run them.

AUTOSPORT understands that he is running one of the engines he has already used before in practice, but will have put in a new power plant by the time qualifying starts on Saturday.

"We are hopeful that we won't have to take a new engine," Horner told AUTOSPORT. "We believe that with the mileage that we have left on existing units and the two new units that are available, we won't need to incur a penalty.

"Inevitably, there will be a slight knock-on effect as we trim mileage slightly on Fridays at the next couple of events."

Horner said that the engine failure Vettel suffered in the race at Valencia, which came despite the engine being unused before the previous day's qualifying session, was down to an error that Renault was responsible for.

"It was basically an engine failure that was caused by what looks like human error," said Horner. "It's a Renault issue.

"The install of the engine resulted in a little bit of damage in qualifying. We had some concerns going into the race but we were still sufficiently confident that the engine should get to the end, based on Renault's advice, to race the engine."

Horner insisted that the double Renault engine failure in Valencia would not influence the team's decision on what engine supplier to use next year. The team is currently in talks with Mercedes about a supply deal, with a final decision on 2010 expected soon.

"We've had good support from Renault for the last three years," said Horner. "You don't judge a partnership based on one race.

"We'll be making a decision imminently about engine partners for next year."