Red Bull may swap engines in 2011 Christian Horner has indicated there is no guarantee that Red Bull will still be powered by Renault engines beyond 2010.
The team principal is quoted by Italy's Autosprint as saying he is happy with the relationship between Red Bull and Renault, but he reportedly wants the French marque to be allowed to catch up the power deficit to the leading suppliers.
"We've shown that we have an excellent chassis, but the engine has maybe 20 or 30 horse power less than the competition.
"We are happy with the relationship with Renault," said Horner, who wanted to switch Red Bull to Mercedes engines this year but was vetoed by the German supplier's existing customers.
"The problem is, as it always has been, that under the current regulations, the way that the freeze currently is, you freeze in advantages and disadvantages, and you might think it is ironic that I sit here talking about an engine disadvantage despite having six pole positions and three wins.
"But I think it demonstrates the job the guys are doing with the chassis, they are doing a phenomenal job at the moment because we probably are 20-30bhp down on the class of the field.
"While we enjoy a chassis advantage at the moment, that might not be the case in two or three races times, and then the engine becomes a determining factor, and once you have frozen a product to freeze an advantage or a disadvantage for a three or four years period is unfair.
"The manufacturers need to get together among themselves and agree a formula to move forward."