Renault make upgraded engine available for Red Bull and Toro Rosso

Red Bull and Toro Rosso will be able to make use of Renault's upgraded power unit from this weekend's 2015 Formula 1 United States Grand Prix, the French manufacturer has confirmed.

Whether either team elects to do so remains to be seen, however, given that they would also be forced to take grid penalties as a result.

"We will have our new specification of power unit available to use in Austin," Renault's director of operations Remi Taffin said.

"The principal changes involve the internals of the ICE (internal combustion engine) to give improved power and efficiency. We know that introducing the new PU will incur a grid penalty so the decision to use will be made in full consultation with the teams.

"At this point of the season obviously points are crucial so if circumstances allow then we will use on track."

Renault, the last of the four power unit suppliers to dip into their allocation of engine development tokens, said they are confident about Red Bull's and Toro Rosso's potential this weekend regardless of whether either team takes on the revised unit.

"Whatever spec we do use, we are looking forward to Austin," Taffin added. "Our reliability has been good in the last three races and performance more in line with our expectations; both our teams just need a clean weekend to show the improved potential of both packages.

"There's very little not to love about Austin. The setting is impressive, the welcome is warm and the track is one of the best we visit all year. There are some very impressive corners and flowing complexes that challenge drivers, engineers and the technology we use."

Negotiations as to which power units both Red Bull and Toro Rosso will use in 2016 continue.