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Image: - Dr. Rüdiger Szengel, Director Gasoline Engine Development

Having been triumphant in this class for the last four years, VW’s TSI Twincharger engine faced major competition this year in the form of Fiat’s innovative MultiAir technology, the new 1.3-litre hybrid powertrain in the Honda Insight and VW’s own 1.2- litre TSI unit that somehow churns out 105bhp. But as the votes rolled in, it soon became apparent that these three powertrains were mere pretenders to the crown, with the TSI comfortably winning the 1-litre to 1.4-litre class once again.

A frugal 1.4-litre engine, TSI Twincharger can deliver up to 178bhp in certain applications due to the combination of petrol direct injection, a turbocharger and a supercharger. Low-end torque is ensured at low speeds by the mechanically driven supercharger. The turbocharger takes over at higher speeds once the intake air is pressurised, filling the ‘hole’ in the torque at low revs, and blessing the diminutive engine with the sort of power usually associated with a 2-litre naturally-aspirated unit.
The ambitious power output targets could not be achieved with a single-stage supercharged or turbocharged 1,400cc engine alone, but with this combination, the upstream compressor increases the boost pressure of the exhaust turbocharger to impressive levels. The turbo and the supercharger have a pressure rating of 1.53 bar, and the maximum system boost pressure is set at 2.5 bar at 1,500rpm.

Power is only half the story, as the innovative TSI engine offers fuel economy benefits over its larger, similarly powered rivals, returning fuel consumption figures in the new-generation Volkswagen Golf of around 6.2 l/100km (45.5mpg), compared with 10.6 l/100km (26.6mpg) for Volkswagen’s 2-litre FSI, which is of comparable performance and power output.

As Nikos Kounitis of 4Wheels said, “Supercharger combined with turbo, fuel efficiency combined with performance; a brilliant idea with an exciting result in fuel economy.”