Holden Astra 2006 Review

With the rush of new European diesel cars hitting the Australian market it comes as no great surprise that Holden's entry into the booming diesel passenger car sector comes courtesy of the small Astra hatch. As its only mainstream European-sourced model in the Holden lineup, the Astra has long been available with a diesel engine in Europe and the UK so bringing the car to Australia was not a great stretch.

It also competes in what is probably the biggest diesel sector with proportionately high sales of Volkswagen Golf, Peugeot 307 and Citroen C4 being diesel variants. Diesel passenger car sales have more than doubled over the same period last year -- albeit still off a relatively small base -- and most carmakers are scrambling to get into the market.

The Astra diesel is not Holden's first with the company having sold a Gemini with an Isuzu-sourced diesel in the early 1980s but the Astra -- along with the current crop of diesel cars -- is a far cry from the low-powered, noisy and dirty diesels of the past.

The newer generations of common rail diesel powerplants are generally smooth and refined, clean and fuel-efficient and offer substantial amounts of low-mid range torque.

And Holden's Astra diesel fits the mold. There are two models on offer that differ only from a mechanical perspective, largely the drivetrain. Although both the six-speed manual and six-speed automatic are mated to a 1.9-litre turbocharged four-cylinder, the block and capacity is about the all the engines share.

The manual version uses a twin-cam 16-valve head that enables outputs of 110kW at 4000rpm and 320Nm at 2000rpm while the auto makes do with a single-cam, eight-valve head that only delivers 88kW at 3500rpm and 280Nm at 2000rpm. The manual also sits on a firmer, lowered suspension and has a sharper steering ratio that helps emphasise Holden's intent that despite the turbodiesel engine, this is sporty Astra.

While both models share a five-door body style and comprehensive standard kit list that includes air-conditioning, power windows and mirrors, remote locking, cruise control and a good sounding quality single-slot CD audio system with steering wheel-mounted controls, the drivetrain differences make these two quite different cars to drive.

Apart from the drivetrain, however, this is standard five-door Astra fare. Slip into the driver's seat and there is a multitude of adjustments for the seat and steering column to enable you to get a decent driving position. There is plenty of space for bodies -- the 60/40-split rear will take two adults in reasonable comfort for short trips -- but a noticeable lack of storage areas. The seats themselves, while supportive, are very firm and flat and could really do with a bit more shape for comfort.

CarPoint started with a week in the automatic and while many new diesels are almost indistinguishable from petrol engines in terms of noise, the Astra's diesel is not among them.

From both inside and out, there is a very distinctive diesel tick at idle that slowly dissipates as the speed of the car increases but when stationary at the lights or backing out of the driveway leaves you and others in no doubt that the car is a diesel.

Off the line, the auto Astra is reasonably enthusiastic but the engine really doesn't hit its stride until it is revving over about 2000rpm. From there it pulls steadily and strongly through to just over 4000rpm with the slick auto transmission shifting up gears in a refined and unfussed fashion.

As mentioned, once off idle the noise becomes less apparent and the engine is reasonably smooth and refined with the auto transmission offering well-spaced ratios that mate easily with the engine characteristics. It is reasonably responsive to right foot pressure and will quickly drop a couple of gears for overtaking and if you want to shift your own, there is a sequential manual function.

As with the rest of the Astra range, the ride and handling compromise is good with a slight bias towards the latter although in the automatic transmission CDTi the ride quality is firm but still offers enough compliance to remain comfortable over most surfaces.

With a lowered and firmer suspension tune, the six-speed manual Astra diesel however, can get a little uncomfortable over rough surfaces. It does tend to get a bit jiggly on patchwork tarmac and it crashes over bigger potholes and bumps. Without any great comfort from the seats, this can, over time, become tiring.

There is however a payoff in the sharper handling with a quicker steering ratio making the manual car feel more lively and responsive at the wheel. Both models are competent through the twisty bits but with the firmer tune, the manual seems to feel that bit more tied down and solid on the road.

It also, obviously has the extra grunt to go with the sharper handling but the characteristics of the engine mean that the difference is greater than just a case of more mumbo.

Peak power is reached at higher revs and when combined with the extra 40Nm at 2000rpm, there is a slight feeling of lag when powering off the line. Once the engine is spinning over 2000rpm, the abundance of torque makes its presence well and truly known and it will keep pulling until about 4500rpm.

Keeping the engine spinning in its power band is reasonably easy courtesy of the slightly notchy but well defined six-speed manual box while a "sports" switch rejigs the mapping for the throttle response and electric steering to further increase the sharpness of the car.

Both models feature bigger ABS-equipped brakes than the petrol engined kin and they do a good of pulling the car up sharply although they do have a tendency to bite sharply at lower speeds. Both diesel Astras also come standard with ESP and traction control -- especially handy in the manual on wet roads -- with the systems calibrated for enthusiastic driving and intervening only when essential.

Along with the rest of the diesel brigade, Holden is pushing the fuel economy benefits with the manual officially listed at returning 6.0l/100km and the auto 7.4l/100km.

After a week in the manual without being too conscious of economy, CarPoint achieved 6.9l/100km, which for a sporty driver, we considered a fairly good result. Our fuel consumption in the auto however, was less impressive for a diesel -- and especially considering the more cruisy conservative nature of the vehicle -- with a final figure after 350km of mixed city and country of 7.8l/100km.

Whether you prefer comfy cruising or driving with a harder edge, Holden has a diesel Astra to suit and while the two cars will definitely appeal to different types of buyers, either makes a better choice of Astra than the petrol variant.