The multi-motor hybrid powertrain of the 508 PSE is similar to the one used by that experimental 308 of a few years ago; but the ways in which it is different reveal a lot about the limitations of using electric motors, batteries and combustion engines in performance cars, and the challenges as regards robustness of power generation, and management of both weight and heat, that will exist for all car makers that attempt the same switch Peugeot is now making.
Just like the 308 Hybrid R, this 508 uses a front-mounted 1.6-litre turbocharged four-cylinder petrol engine as its primary source of power and also has an electric drive motor for each axle. The front motor is sandwiched between the petrol engine and an eight-speed automatic gearbox, and the rear one drives the rear wheels via reduction gearing.
The electric motors could make as much as 110bhp each, which is roughly as they did on the Hybrid R, but the 508 PSE’s combustion engine is rated to produce only 197bhp, down from 266bhp in the 308 Hybrid R.
That change may allow the motor some margin to work as a current generator without affecting how much power it can supply to the front wheels but it is just as likely to be about preventing it from producing so much heat that the electric half of the car’s propulsion system becomes adversely affected.
Peak ‘system output’ for the 508 PSE is 355bhp, rather than the 400- odd you might have just tallied up, and peak torque is a combined 384lb ft on tap from just 500rpm.