Red Bull master designer Adrian Newey has mocked Formula One's new engine rules, claiming they have produced slower cars without achieving the intended green goals.
Speaking ahead of Sunday's Bahrain Grand Prix, Newey, who designed the cars that won Red Bull the past four drivers' championships, said the new 1.6 litre V6 turbo hybrid engines have increased costs and slowed down the cars for little benefit.
For an engine to deliver similar power to last year, with more than 30 percent less fuel consumption, is just an incredible achievement and it's something we should celebrate.
He said the environmental aims of the hybrid engine could have been more efficiently met by reducing the cars' weight without compromising speed, and that there were more ways to be relevant to commercial car production than fuel efficiency alone.
The new engines have been criticised both for creating a muted sound, and also for producing a processional style of racing as cars circulate in fuel saving mode to stay under the 100 kilogramme per race limit.
"Formula One should be about excitement," Newey said.
"OK, they're using 50 kilos less fuel (per race) but they're going a lot slower to achieve that."
However, rival engineers disagreed with Newey, saying the sport had risked becoming too far removed from normal commercial engines and that the technological innovation should be celebrated rather than criticised.
Paddy Lowe, the technical chief of Mercedes who has dominated the early stages of the season, was surprised by criticism of the changes.
"For an engine to deliver similar power to last year, with more than 30 percent less fuel consumption, is just an incredible achievement and it's something we should celebrate," Lowe said.
Bob Fernley, the deputy chief of Force India, said the efforts to make the engines more relevant to road-car production have already borne fruit.
"Honda are coming in next year and it's the first time we've had another major motor manufacturer coming back into Formula One for a long, long time, so that's a tick in the box that says that actually Formula One has got it right," Fernley said.