Revealed: How Mercedes' packaging of their turbo engine has given them the edge

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Sky F1 analyst Hughes has learnt that, in a highly complicated engineering feat, the team have successfully packaged their turbine and air compressor at either end of the W05's engine.

The innovative design - which, like the best ideas, sounds simple, is vastly complex and brilliantly effective - is believed to have been conceived over two years ago.

The revelation is also the best explanation yet for why the W05 has so far proved unbeatable in 2014, with Nico Rosberg's cruise to victory in Australia followed by Lewis Hamilton scoring F1's version of a hat-trick - pole position, the fastest lap of the race and victory - in Malaysia on Sunday.

Hughes has learnt that the Brackley team's ties with Mercedes High Performance Engines gave them a critical headstart at the start of F1's new turbo age.

Looking to achieve the most aerodynamically efficient car possible, the Mercedes team had significant influence over power unit design created at the German manufacturer's engine base in Brixworth.

Writing in Motorsport magazine, Hughes discloses that Mercedes' breakthrough 'innovation is having the turbo's compressor at one end of the engine and the turbine at the other, linked by a long shaft through the vee of the engine'.

The 'trick turbo layout' triggers a series of critical performance benefits. As the air is not travelling through as much pipework, a reduction in turbo lag means less power needs to be be harvested from the car's ERS unit to keep the turbine spooled off throttle. That in turn improves the efficiency of the car, with more power reserved for performance gain and less fuel consequentially used up.

Mercedes' customer teams all have the same advantage. However, because McLaren, Williams and Force India only took delivery of their power units relatively recently, they have had less time to work the layout into their respective car designs.

But for the works outfit, the benefits of the W05's innovative layout has proved multifaceted.

With the compressor further away from the turbine - which is spun by hot exhaust gases - the W05 has a smaller intercooler, meaning Mercedes are running with smaller sidepods which boost aerodynamic performance.

Furthermore, with the compressor in front of the engine, Mercedes have also moved their car's gearbox forward, improving its centre of gravity and therefore, in theory, its handling.

But while Mercedes' rivals are aware of the championship leaders' secret, they are essentially powerless to react. The engines for 2014 are now in lock-down, with February 28 marking the agreed homologation date by which all the teams had to register their design for the new season with the governing body, the FIA.

"We're talking about 2014's double diffuser with the exception that you can't copy it this year," Hughes said during Sky F1's live coverage of the Bahrain GP.

"Its impact is maybe not quite as big as active-ride, but it's certainly a major technical advantage that they've engineered themselves for the rest of the season."

The Mercedes power unit has been widely credited as being the critical performance differential in their victorious start to the new season. Red Bull boss Christian Horner claimed in Malaysia that his team was one second slower along the straights, with trackside observers estimating that the Mercedes unit boasts anything between 50 and 70 extra horsepower over the rest of the field.

Sky Sports F1's exclusively live coverage of the Bahrain GP begins at 2.30pm UK Time, with the race underway at 4pm