Small turbocharged engines are cropping up with increased regularity in our mid-sized cars and the Vauxhall Astra 1.4 VVT Turbo neatly explains why, says Steve Walker.

Small turbocharged engines are cropping up with increased regularity in our mid-sized cars and the Vauxhall Astra 1.4 VVT Turbo neatly explains why, says Steve Walker.

It achieves a smooth 138bhp with combined economy close to 50mpg which is enough to make you question the need for diesel. The Astra itself sets a high standard for comfort and refinement and is at its best with this engine.

The 1.4-litre family hatchback has never been a particular focalpoint of automotive desire. A decent 1.4-litre petrol engine will typically give you about 100bhp and that isn't a lot for shifting a fully-laden family car up a hill. Vauxhall offers a normally-aspirated 1.4-litre VVT engine at the base of its Astra range and this will be adequate in most situations but the 138bhp 1.4-litre VVT Turbo opens up a world of extra possibilities. A 9.0-second 0-60mph time compares very favourably with the 13.1 seconds it takes the 98bhp 1.4, while the 200Nm maximum torque means overtaking manoeuvres and challenging gradients can be dispatched with far more ease.

Modern turbochargers are a whole lot more advanced than the blunt instruments that were being bolted on to engines a few years back. The Astra 1.4 VVT Turbo has a water-cooled unit, capable of spinning up to 200,000rpm, integrated into its exhaust manifold. It's designed to bring faster throttle response and a smoother power delivery in stark contrast to the worst turbocharged cars of yesteryear which responded to throttle inputs with an extended pause followed by a mule-like kick of power that overwhelmed the tyres. In the Astra, it's tough to detect a turbo at work as the acceleration pours on seamlessly. The experience would be like that of a 2.0-litre petrol car were it not for the 1.4 Turbo's superior flexibility and torque in the middle of the rev-range.

The Astra handles with composure and while it can't quite match the agility and feedback of the Ford Focus, its more relaxed, comfort-orientated approach will be preferable for many buyers. The ride quality is the highlight, with the car staying unruffled even over big undulations and rough surfaces. There's plenty of grip and a very limited degree of body roll in the corners, so only the rather lifeless steering really counts against it.

It's possible to get the 1.4 VVT Turbo engine in Exclusiv, SRi, SE or Elite trim. Exclusive will be a popular choice, with all the basics like ESP stability control, air-conditioning, a CD stereo and six airbags included at a reasonable price. SRi is Vauxhall's mainstream sporty trim level and includes 17in alloy wheels with lowered sports suspension while the SE and Elite models take a more luxurious line.

Astra pricing isn't quite as affordable as it has been in the past compared to rivals with Vauxhall rightly assuming that it now has a product that can match the sector's best in terms of quality.

The 1.4-litre VVT Turbo engine is available with manual or automatic gearboxes and with the advanced FlexRide adaptive damping system that adjusts the car's damper settings according to the driver's preference. Priced about �700 less than the 108bhp 1.7-litre diesel, this small turbocharged engine seems destined to be a popular choice.

PRICE: Vauxhall Astra 1.4 VVT Turbo, �17,290-�20,470 on the road

PERFORMANCE: 0-60mph, 9.0 seconds; top speed 128mph

MPG: Urban 36.2; extra urban 58.9; combined 47.9

EMISSIONS: 139 to 164g/km

INSURANCE GROUP: 8-10 (estimated)

WILL IT FIT IN THE GARAGE: Length 4,419mm; width 1,814mm; height 1,510mm