SECTOR Upper Medium  PRICE €39,200 – €42,200  FUEL 3.6l/100km  CO2 95g/km

While Citroën has launched its Hybrid4 diesel-electric drivetrain as a high-performance four-wheel-drive option in the executive-class DS5, Peugeot’s approach has been to highlight its off-road credentials in the 3008 crossover and Audi

Allroad-alike 508 RXH, until now.

The 508 HYbrid4 saloon breaks that trend. It uses the same 163hp diesel engine and 37hp electric rear axle as the RXH, but sheds the rugged cladding and raised ride height. Instead of marketing its ability to cross rough terrain, this new model becomes the most efficient 508 and one of the most powerful too.

For most European markets, it’s the model which makes more sense for fleets, because at 95g/km it qualifies for a number of tax benefits to offset a price increase of over €5,000.

The drivetrain is well packaged. Peugeot has fitted the motor and battery under the boot floor, and the only visual clues come from a HYbrid4 badge on the grille. The downside is a noticeable drop in luggage capacity, and drivers regularly carrying bulky loads may find the remaining boot space a little shallow.

Interior differences are as easily missed, confined to a hybrid display in the instrument binnacle, mirrored on the satellite navigation screen, and a power gauge which replaces the tachometer.

HYbrid4 is available in two trim levels. For most markets, it is based on the 508 Allure, and includes 18-inch alloy wheels, electrically adjustable half leather heated front seats, keyless entry and start and Peugeot’s intuitive infotainment system with satellite navigation and Bluetooth. A higher spec, based on the Feline trim, is also available in some countries.

On paper, at least, it’s an impressive all-rounder. There’s a combined 200hp power output, the option to drive short distances using electricity and 3.6l/100km fuel

consumption, resulting in a tempting balance of efficiency and performance that’s difficult to match in the D-segment.

HYbrid4 starts in economy-prioritising Auto mode, one of four which can be selected by the driver. This makes the most efficient use of diesel and electric power, and feels like a stop/start system, which shuts off the engine more frequently.

Efficiency can be boosted further by selecting ZEV pure electric mode at low speed, depending on battery charge.

The remaining 4WD and Power modes combine the two power sources for an electric ‘boost’ function or extra grip as required, and the electric motor also cuts in to smooth gaps in power between gear changes from the sluggish electronically-controlled gearbox.

But, with an additional 140kg, it’s not a fast car. Performance is brisk, but the hybrid is outpaced by the equivalent conventional diesel, and this isn’t its biggest problem.

Early road tests of the 3008 HYbrid4 criticised its poor economy, and the 508 suffers a similar issue. Drivers expecting close to the claimed 3.6l/100km will find its real-world economy of between 5.1 and 5.6l/100km disappointing, as other non-hybrid 508s easily return similar figures. There’s a skill to extracting the best economy from the system, helped by forcing the electric motor to assist the diesel engine at high speeds.

Ultimately, its downfall appears to be a lack of ability to ‘sail’ on electric power at motorway speeds and disconnect the diesel engine like some other large hybrids. This omission means the saloon makes the most sense as a low-pollution urban car with many tax benefits as its most obvious attraction.

Verdict

The 508 HYbrid4 offers a tax-conscious high performance option no competitors can match. It’s a shame the high speed efficiency struggles to meet Peugeot’s claimed figures.