• British Grand Prix

Engine performance turned down for reliability - Renault

ESPNF1 Staff
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The Renault engine uses exhaust blowing to cool its exhaust valves © Sutton Images
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Renault Sport has had to reduce the performance of its engines to ensure they are reliable under the exhaust regulations for the British Grand Prix.

The Silverstone weekend has been peppered by FIA technical directives dictating what the teams can and cannot do in relation to off-throttle exhaust blowing. On Friday Renault Sport was given a concession for reliability purposes to continue to keep the throttles 50% open when the driver was off throttle, but that was withdrawn on Saturday morning.

Forty five minutes ahead of qualifying the teams met for an extraordinary meeting of the Technical Working Group on the issue and agreed to run with the restrictions in place, albeit with a view to discussing the issue in the future. That decision had a well publicised effect on diffuser performance, but Renault Sport, which supplies Red Bull, Renault and Lotus, told ESPNF1 that it would also affect the performance of the engines this weekend.

"For sure, every additional constraint has the effect of reducing the scope to optimise the performance of the engine within the same reliability window," Renault Sport Deputy Technical Director Rob White said. "I guess the fundamental underlying question is whether that effect is greater for one subset of the grid or another - one group of teams or another, one engine or another and even within the same group of engines one group of teams or another."

He said the main problem for the Renault engine was cooling the exhaust valves, which had previously been done by electronically managing the throttles when the driver was off the accelerator.

"I think like everybody does, we juggle all of the available control parameters to achieve the best compromise of performance and reliability," White added. "Specifically when it concerns exhaust valves then one of the things that is a problem is the heads fall off if you make them too hot for too long.

"So one of the things you do is control the throttle position, spark and fuelling to manage the time-temperature profile of the exhaust valves, and I guess we acquired some operating procedures which had been developed over some time with all of the teams. The discussion is where we are now compared to a few races ago and where we will be in a few races time."

He said having a moving target with the regulations over the weekend had caused the biggest headache. "All of these things adjust setup parameters and what is kind of awkward is dealing with a space which changes and the way in which that is handled is a bit uncomfortable for everybody."

When Renault team boss Eric Boullier was asked if he had any reliability concerns ahead of the race, he said: "We have some."

He added: "We know that the margin is very, very close to where we don't want to be."

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