VAUXHALL INSIGNIA DIESEL HATCHBACK 2.0 CDTI ECOFLEX EXCLUSIV [160] 5DR [START STOP]

Vauxhall's environmentally-friendly Insignia ecoFLEX isn't resting on its laurels. Steve Walker reports.

VAUXHALL INSIGNIA DIESEL HATCHBACK 2.0 CDTI ECOFLEX EXCLUSIV [160] 5DR [START STOP]

The Insignia ecoFLEX certainly hit the ground running. With 158bhp and up to 380Nm from its 2.0-litre CDTi diesel engine, it clearly packed a bigger punch than the majority of these eco-special family cars. It looked good too with its lowered ride height and sleek lines, Vauxhall has recently followed it up a lower-powered ecoFLEX, tipping the balance towards seriously good economy and low emissions without giving away too much raw performance.

VAUXHALL INSIGNIA DIESEL HATCHBACK 2.0 CDTI ECOFLEX EXCLUSIV [160] 5DR [START STOP]

There's no bigger issue facing the automotive industry today than the great big green issue. It wasn't that long ago, however, when many manufacturers were still content to pay lip service to it and hope it would go away. Legislation has changed all that and today, waiting for hydrogen fuel cell cars to arrive and save the planet at a stroke is not an option. Manufacturers have been forced into looking at short term ways of reducing emissions and saving fuel by a combination of new legal requirements and public demand. Cars like the Insignia ecoFLEX from Vauxhall are the result. Relying on simple engineering ingenuity rather than major technological advances, they might not be planetary saviours but they are a step in the right direction.

VAUXHALL INSIGNIA DIESEL HATCHBACK 2.0 CDTI ECOFLEX EXCLUSIV [160] 5DR [START STOP]

There are now two Insignia ecoFLEX models based around Vauxhall's 2.0-litre CDTi ECOTEC diesel engine. The recent addition of the 128bhp unit is equipped with a stop-start system for the first time, while aerodynamic enhancements and low-rolling resistance tyres also help bring down the headline CO2 figure.

With this engine under the bonnet, the Insignia ecoFLEX has a top speed of 129mph, and a 0-60mph time of 10.4s compared to 137mph and 8.9s for the 158bhp version. Torque outputs are 221lb ft and 258lb ft respectively.

Whichever state of tune you go for, the Insignia's 2.0-litre diesel engine is an advanced piece of kit. It uses Vauxhall's Clean-Tech process to control emissions consistently through the different stages of its lifecycle. The combustion process in the cylinders is monitored up to one million times per minute so the engine management computer can adapt the volume and timing of the fuel injections to optimise efficiency.

VAUXHALL INSIGNIA DIESEL HATCHBACK 2.0 CDTI ECOFLEX EXCLUSIV [160] 5DR [START STOP]

Aerodynamics play the major role in the environmental performance of the Insignia ecoFLEX. The car is 10mm lower than a standard model which has the happy side effect of giving the car a more purposeful ground-hugging stance. There's also a number of modifications out of sight underneath the car which improve air-flow and lower drag while the radiator grille is partially closed off to send more air down the flanks of the car. The ecoFLEX also runs on Michelin's special low rolling resistance Primacy HP tyres.

The standard Insignia's sleek shape has a drag coefficient on 0.27 CD but the ecoFLEX model lowers that to 0.26. It sounds a trivial amount but the laws of physics reveal otherwise. When you double the speed of a car, the amount of engine power necessary to overcome the aerodynamic drag increases by a factor of eight. That means that even the tiniest improvements in aerodynamic performance can significantly reduce the amount of work the engine needs to do at a given speed, reducing fuel consumption. These aerodynamic enhancements have the additional benefit of reducing wind noise in the cabin and making the Insignia a more comfortable place to sit out long journeys.

VAUXHALL INSIGNIA DIESEL HATCHBACK 2.0 CDTI ECOFLEX EXCLUSIV [160] 5DR [START STOP]

The Insignia ecoFLEX goes up against a raft of eco-friendly rivals in the medium range sector and the battle for sales is likely to be anything but friendly. Vauxhall is obviously hoping that its offering will gain an edge by virtue of its hefty performance as most of the alternatives utilise relatively weedy powerplants to make their efficiency savings. Of course, the Insignia's additional pace will be reflected in the price.

VAUXHALL INSIGNIA DIESEL HATCHBACK 2.0 CDTI ECOFLEX EXCLUSIV [160] 5DR [START STOP]

The ecoFLEX's reduced combined CO2 figure of as little as 115g/km means that business drivers will pay just 13 per cent Benefit in Kind tax - the lowest band for a diesel car - down from 21 per cent for the already competitive non-ecoFLEX 2.0 CDTi models. The lower CO2 also mean that for owners of the lower-powered Insignia there is no VED on the hatchback and saloon, and no VED in year one on the Sports Tourer (estate).

And with all drivers keeping a keen eye on the fuel gauge these days, the Insignia ecoFLEX rewards with an official combined figure of 57.6mpg - a 10 per cent improvement on the 2.0 CDTi model - which puts it among the best in class. It also means that the Insignia ecoFLEX now has a potential range of over 850 miles.

VAUXHALL INSIGNIA DIESEL HATCHBACK 2.0 CDTI ECOFLEX EXCLUSIV [160] 5DR [START STOP]

Going green doesn't have to mean reinventing the wheel or the internal combustion engine for that matter. Vauxhall's Insignia ecoFLEX shows how much can be achieved with a slippery shape, an advanced diesel engine and some skinny tyres. Better yet, it achieves its efficiency gains without making the compromises that some of its rivals force on their owners.

Styling, performance and comfort don't suffer in the Insignia ecoFLEX and that can only help persuade buyers to take the greener option. That and the significant fuel economy and tax savings they stand to make.