A LINE up of new eco-friendly engines is set to transform the latest Vauxhall Astra increasing its appeal to those who want to make a killing on the fuel front.

Fuel economy and emissions are down by up to 21 per cent thanks to a new range of three-cylinder engines developed by Vauxhall and its sister brand Opel.

The new model will be on the road in November and the engines comprise 1.2 and 1.4-litre petrols while a 1.5-litre diesel is also available.

Six-speed manual gearboxes are fitted to the 1.2 engines and the diesels while a new CVT box is used on the 1.4. The diesels also come with the choice of a new nine-speed automatic transmission.

Prices are up by a couple of hundred pounds and the new range starts from £18,885 for a 1.2-litre developing 110ps, £20,875 for the 1.4 which has 145ps on tap and £19,305 for the diesel which comes in 105 and 122ps states of tune.

The automatic option is fitted to the higher powered engine and costs from £21,985.

Seven trim levels are being offered with the range topping out from £26,755 for an Ultimate Nav model fitted with a 145ps derivative of the 1.2-litre engine.

We have just tried out the new Astra fitted with that engine as well as sampling the 1.4 with what Vauxhall calls its stepless transmission and the new automatic diesel.

The powertrain changes are telling and keep the facelifted Astra up with alternatives such as Ford's Focus and the VW Golf.

Cosmetically, the new Astra gets a fresh face which incorporates an active shutter arrangement in the grill which has helped to reduce drag and makes the car the most aerodynamic in its class.

That has helped on the fuel front and the diesel version has a CO2 rating as low as 90g/km for the 105ps engine which equates to 83mpg. The automatic has an equally impressive emissions figure of 112g/km which works out at almost 67 to the gallon.

While we couldn't quite match that - on an eco run the diesel Astra notched up an average of 62mpg and in regular driving 40.4 to the gallon - it is streets ahead of the previous 1.6-litre block in terms of all round performance and quietness.

Performance figures for the diesel auto are a top speed of 127mph with a 0 to 60 acceleration of 10 seconds and the gearbox has a smooth pattern although it was lacking paddle shifters.

The stepless transmission in the 1.4-litre is equally impressive and its a CVT box that has almost eliminated any feeling of surge as it goes through its paces.

It is rated at 48.7mpg at best under the new WLTP fuel test programme although we saw a return of 35.1 to the gallon over a similar run to the diesel. Emissions are 112g/km and the car has a maximum of 130mph with a nine second 0 to 60 time.

On the road the best performer was the Astra with the 1.2 engine which was not only the quickest of the bunch - 0 to 60 in 8.8 seconds and a top end of 137mph - but is also rated at 54.3mpg with a CO2 figure of 99g/km.

We managed to average 45.9 to the gallon which for such a lively performer is quite credible.

Compared to the previous 1.0-litre turbo Astra the new block is some six kilos lighter and the revisions for the facelift also include a new damping set up as well as changes to the steering which have both improved the car's demeanour.

Other changes include a brake-by-wire set up and on the technology front the latest Astra can be fitted with an eight-inch display screen and an upgraded media system which is fully smartphone compatible.

A new forward facing camera now gives the car pedestrian as well as vehicle detection while LED matrix headlights can also be specified as can a new-look digital instrument panel.

While Vauxhall is now owned by French auto group PSA the new engines have been developed in-house by engineers at the Opel factory in Germany and the car itself is built in the UK at Vauxhall's Ellesmere Port factory in Cheshire.

The revisions deployed in the hatchback also come on stream in the Astra Sports Tourer estate models which are now priced from £20,355 for a 110ps 1.2 in base SE trim to £26,930 for a manual diesel.

Although the stepless automatic is included in the estate range priced from £26,035 it is the only two pedal option and the diesel automatic is available in the hatchback versions only.