The FIA has announced that the new 1.6L V6 turbo engines will have a rev limit of 15,000rpm and will still ensure Formula One has a unique sound.

9970 - FIA announces 15,000 rpm limit

There has been speculation of what the limit would be as Bernie Ecclestone and the circuit owners had voiced their concerns at the sound of the new engines. After Adrian Newey told BBC Sport in Valencia that he expected the limit to be "around 14,000 or 16,000", the FIA announced in a Q&A press release that the limit had been agreed on a middle ground.

"This parameter has been updated from 12000rpm to 15000 rpm to allow engineers more flexibility in power and energy management," the FIA release read. "However, as a consequence of the new architecture (V6) and the change in rev-limit, the engine will sound different, but will remain representative of Formula One."

The clarifications come after the FIA ratified the new power units for 2014 on Wednesday. In a further challenge to the engineers, the FIA announced that the fuel flow had not changed from the initial limit imposed in order to force the engines to be even more efficient.

"The fuel flow limit will stay the same. The technologies are the same and as a consequence any increase in rpm will constrain the engineers to work harder on reducing friction and gaining on engine efficiency. The challenge will be even bigger than originally planned and will therefore enhance the technological lead of Formula One."