The Polo BlueGT, unveiled on Tuesday at the Geneva Motor Show, attempts to combine dynamic performance with extreme fuel efficiency, thanks to the use of ACT cylinder deactivation, which is being used for the first time in a production Volkswagen.

The turbocharged 1.4-litre four-cylinder engine produces 102kW, yet returns a combined cycle fuel consumption figure of just 4.7 litres per 100km, and emits a forecasted 108g/km of CO2. Opt for the seven-speed DSG transmission, and fuel consumption drops to a forecasted 4.5 litres per 100km and CO2 emissions of 105g/km. Top speed is 210km/h and zero to 100km/h takes 7.9 seconds.

At the heart of the Polo BlueGT, and responsible in large part for its combination of high performance and low fuel economy, is the first of the new EA211 series of engines, which will become commonplace in the new modular transverse matrix (MQB) that will underpin future Volkswagen models.

Under light and medium loads, the second and third cylinders are automatically shut down, producing fuel savings of up to 0.4 litres per 100km in the EU driving cycle. At a constant 50km/h the savings can be as much as one litre per 100km, and even at 70km/h in fifth gear, around 0.7 litres per 100km can be saved.

Cylinder deactivation occurs at engine speeds of between 1250 and 4000rpm, and at torque outputs of 25 to 100Nm. If the driver presses the accelerator pedal, the two cylinders are imperceptibly re-activated. All mechanical switchovers occur within 13 to 36 milliseconds, depending on engine speed. The multifunction display in the instrument binnacle lets the driver know when cylinders are de-activated.

While the cylinder de-activation is so unobtrusive that only the driver might know about it, the Polo BlueGT itself is distinguished both inside and out by various styling cues. On the outside, there are multi-spoke 17-inch alloys and GT badges front and rear. The suspension is lowered by around 15mm. Added to this are some features borrowed from the Polo GTI (the rear spoiler, rear bumper with diffuser, plus front bumper with LED daytime running lights) and some features borrowed from the Polo BlueMotion (side sills and front windscreen rain channels). A black-painted front grille and black door mirror caps complete the look.

Inside, as in the Polo GTI, the roof lining is in black, while the instruments are also from the GTI. Both driver and passenger sit on bespoke BlueGT sports seats, and there is a leather-trimmed steering wheel with BlueGT emblem.