The McLaren M838T engine is a 3.8-litre (3,798.6 cc) 90-degree twin-turbocharged flat-plane V8, designed and developed in collaboration with Ricardo.

[1] McLaren bought the rights to the Tom Walkinshaw Racing developed engine, itself based on the Nissan VRH engine architecture,[2] which was designed for the IRL Indycar championship but never raced.

[3] In only 18 months, Ricardo went from a modified Nissan engine design to a running prototype.

In 2012 McLaren released an update increasing power to 625 PS (616 bhp; 460 kW) at 7500 rpm.

The engine block has also been modified to incorporate an integrated electric motor as part of a hybrid drive train.