Porsche has revealed the car it will use to defend its FIA World Endurance Championship titles in 2017.
This year's 919 Hybrid is a heavily upgraded version of the car that swept the drivers' and manufacturers' championships last season.
It retains both the two-litre V4 combustion engine and the lithium-ion battery recovery system jointly capable of creating around 900 horsepower.
Like the new Toyota TS050 Hybrid, the Porsche has undergone an aerodynamic facelift in accordance with the new WEC regulations designed to control cornering speeds.
Porsche has also adopted a new livery for 2017 that has already been seen on the manufacturer's GTE and GTLM cars.
"For the 2017 season, 60 to 70 per cent of the vehicle is newly developed," said Team Principal Andreas Seidl.
"The basic concept of the 919 Hybrid still offers scope to optimise the finer details and further boost efficiency."
"The monocoque has remained unchanged since 2016, but the optimisation potential of all other components was analysed and, in most cases, adjustments made accordingly.”
Porsche unveiled its car at Monza ahead of the official WEC pre-season test.
Neel Jani, Andre Lotterer and Nick Tandy will campaignt the #1 this season, with Earl Bamber, Brendon Hartley and Timo Bernhard sharing the #2 machine.
View photos of the 2017-spec Porsche 919 Hybrid below.
