From the outside, nothing seems to have changed about the Opel Astra over the past two years: the styling is modern and the car looks good. What’s new is under the bonnet and it changes the driving experience completely. Opel is using a new 1.6-litre turbo-diesel engine that has been dubbed the whispering engine and has made this car a game-changer for Opel.

It’s been a while since I drove an Opel Astra and I was waiting to be impressed. When the current version of the car was introduced in 2013 it looked well. With this new engine there is so much more to the car that will raise Opel’s profile on the Irish market.

Opel has spent on the engine and when it launched this option in 2014 to replace the 1.7-litre turbo-diesel offering, it was a change that was long overdue. The new engine is made almost entirely from aluminium to lower the weight and this, combined with a new fuel system, delivers a better economy performance. I drove the new 110bhp Astra and it is very impressive. Volkswagen’s Golf and the Ford Focus will see the new Astra coming in their rearview mirrors.

The engine produces impressive power. Compared with the Golf and Focus, the power is smooth, giving it a new sense of driver and passenger comfort. Opel has worked in what is called the NVH (noise and vibration harshness) to good effect. Coupled with the smoother and quieter engine, I was very impressed after driving more than 800km behind the wheel.

This new engine brings plenty of torque, minimising gear changes on rural roads. I found, however, that third gear was higher in ratio than I would have expected, so I used second more than usual. In sixth, the Astra cruised on the motorways at 120km/hr with the engine at less than 2,000rpm.

The acceleration is a match for the competition. It can go from zero to 100km/hr in 11.6 seconds and all the way it feels smooth and solid – so much better than the previous 1.7-litre engine. It may sound exaggerated, but this engine changes everything about the Opel Astra. In my mind, it pushes the car into a far more desirable zone, with the added benefit of looking good and offering value relative to the Golf and Focus.

When it comes to economy, this Astra scores well too. Over my 800km of driving, I recorded a figure of 17km/litre (48mpg or 5.8l/100km) across a range of conditions. That’s about 35% less than the quoted economy figure but it’s a reasonable result for my driving style. There’s a 56-litre fuel tank so the range will be close to 900km; I expected a little more. The CO2 rating is 104g/km, giving an annual road tax cost of €190.

Opel claims that the engine is as clean as a petrol engine. Like its petrol counterpart, the 1.6 CDTi benefits from engineering measures that minimise noise, vibration and harshness. Opel claims that it has recorded the lowest in-vehicle noise ratings when tested against other vehicles using 1.6-litre turbo diesel engines. The big impact of the change is the smoothness of the driving experience. Towing rating, however, remains lower than that of the Golf at 1,400kg with a braked trailer.

This car is stylish even if the design is two years old. The interior is impressive. The seats give good adjustment and space in the rear compares with the competition. The boot is also a match at 351 litres – just marginally smaller than that of the Golf, but bigger than the Focus. Opel had a space saver spare wheel in the boot, but it’s on the options list for the range, and worth it at €146 extra.

The one downside on the Astra is that it’s Euro NCAP crash test rating is from 2009. However, the car has plenty of safety gear, including Isofix kit in the rear, so it should measure up.

The other message is the value one. The top-of-the-range test car is priced at €23,995 (£19,770 in NI) including the delivery charge. That’s cheaper than the Focus and Golf by close to €2,000 for a good-looking car that is now a quality drive. If you’re in the market for a mid-range hatchback, you have to give it a test drive. Opel has some scrappage deals that will make the car even more competitive to own, while its 0% finance deal could be the icing on the cake for what is a great car to drive. CL

Opel Astra 1.6 CDTi SE

Engine 1.6L diesel

Engine power 110bhp

0-100km/hr 11.6 seconds

Economy 25km/litre

Fuel tank capacity 56 litres

CO2 emissions 100g/km

Road tax band A2 (€180)

Service interval 30,000km/ 12 months

Euro NCAP rating Five stars (2009)

Towing rating 1,400kg

Warranty Five years