The Japanese manufacturer and partner team McLaren have been tight-lipped about what was changing with its power unit for the season ahead as its bids to build on the lessons of its first two years back in F1.

However, last week McLaren technical director Tim Goss did confirm that there would be a new layout and architecture for the season ahead.

"The new power unit takes much of the learning from the past two seasons, but has been specifically redesigned for this season," he said.

Although no details of the redesign have been revealed, sources have confirmed that Honda's F1 chief Yusuke Hasegawa has given the green light to Honda moving away from the compact 'size zero' concept that has been used for the past two years.

That design – aimed at making the engine packaging as tight as possible – featured a split turbine and compressor situated within the confines of the V-bank of the internal combustion engine.

Believing that the advantages of that concept did not outweigh the drawbacks, for 2017 Honda has decided to go down the Mercedes route – which means the compressor being situated at one end of the engine while the turbo is located at the other.

Just like Mercedes has done too, the two elements of the turbo-charging system will be joined by a connecting shaft that runs between the inside of the V-bank.

As well as that, the water intercooler will be located in a niche between the chassis and the engine, which will significantly lower the power unit's centre of gravity.

Work on the changes are currently ongoing on Honda's test benches at Sakura in Japan.

Despite the dimensions of the power unit being slightly larger than before, it is understood that McLaren is still able to package a very tight rear-end to the MP4-32 around the rear.

As well as the packaging change, Honda has been focusing efforts on improving the internal combustion unit element of its package, with it feeling it had made good gains with energy recovery last year.

It is expected that Honda will adopt a multi-jet injector system to spray fuel inside the combustion chamber, similar to the Turbo Jet Ignition system that Ferrari has put to good use.

The extent of the changes to the Honda has been possible because F1 has scrapped the engine development token system for 2017 – which means that modifications to the power units are now unlimited.