The FIA explains the thinking behind the new for 2014 formula.

The World Motor Sport Council voted on 29 June 2011. What did it decide?
Following consultation with the various Formula One stakeholders and the current Formula One engine manufacturers, the WMSC has ratified the adoption of a V6 turbo engine to be used in Formula One from 2014 onwards. This required changes to the regulations initially adopted by the World Council on 3 June 2011. The full regulations applicable to the 2014 season will be published in due course.

Will a V6 use more fuel, or have inferior economy compared with the original proposal?
No. To push the engineers to develop engine efficiency, the technical regulation imposes a fuel flow control. When evolving the regulation to fit with the manufacturers' new request this parameter has not been changed. Thus the efficiency requirement will be unchanged.

Why has the rev limit been increased from 12,000rpm to 15,000rpm. Is this purely to enhance the sound of a Formula One car?
No. This parameter has been updated from 12000rpm to 15000 rpm to allow engineers more flexibility in power and energy management. 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.

Will the increase in rpm alter fuel consumption?
Absolutely not. As mentioned above, 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.

Has the FIA retained the energy recover devices originally intended to be used in conjunction with the 2014 engine?
Yes, the concept initially presented is respected. All of the technology intended for the 2014 is still present. This new power plant will be a dramatic step forward in both fuel efficiency and in energy management.

Will those manufacturers already engaged in the development of a four-cylinder engine face increased costs now they need to redirect their resources toward designing a V6?
To our knowledge, five manufacturers were working on the proposed 4-cylinder engine. They will all need to adapt their project and this will surely involve some additional costs, depending on how advanced each project was. This evolution has been proposed and supported by all four engine manufacturers currently involved in Formula One.