Review of the new Saab 9-3 Convertible 1.9 TTiD

Guilty as charged, I'm afraid. When I first heard that Saab were endowing their 9-3 Convertible with a 1.9-litre diesel engine, I thought it would be a peaky little thing, all turbo lag and lunge and no flexibility. Putting an engine with this modest capacity into such a hefty drop top surely was a recipe for a dull and stodgy driving experience? I'm glad to report that I was wrong. This is a convertible with a surprising amount of get up and go.

There are a couple of diesel options available in this drop-top variant, both twin-turbos with either 160 or 180PS. Here, we look at the 160PS version. Mated to a six-speed manual gearbox as standard, with the option of a six-speed auto, there's plenty of scope for plugging the car straight into the meat of the torque curve. With at least 90% of peak torque available in a broad load running from 1,750 to 3,250rpm, you'll be guaranteed respectable progress.

As importantly in a soft top car, it also offers impressive refinement. Saab have worked closely with turbocharger manufacturer Garrett to optimise the performance of this unit and the result is very close to that target for all decent turbocharged cars, namely to feel like a normally aspirated bigger capacity engine. The variable geometry vanes in the turbo unit allow the pitch of the blades to be electronically adjusted for strong low-end torque and then tuned to offer a smooth transition into the turbo's power phase.

It's respectably quick too, punting the big-boned Convertible to 60mph in just 10 seconds even in 160PS form but the in-gear acceleration times that really indicate a diesel engine's torque response have been slashed dramatically. Surging from 50 to 70mph in fifth gear - a typical A-road manoeuvre - takes around 8.5 seconds.

"Somewhat against the odds, this 1.9-litre turbodiesel engine makes a very accomplished partner to the 9-3 Convertible"

It's a clean engine too. Unlike other particulate traps, the diesel particulate filter in this unit is maintenance-free and self-cleaning, requiring no additives or periodic replacement. In order to clean the filter and to keep the exhaust flow as free as possible, deposits are periodically burnt off by short pulses of over-fuelling. These briefly raise exhaust temperatures to the required level of 600º C. The process is automatically initiated when back pressure in the exhaust system reaches a certain level and is completely undetectable by the driver. The self-cleaning process takes place whenever necessary, irrespective of throttle load or engine temperature.

When work began on this 9-3 Convertible, Saab's designers were determined to imbue it with the same handling characteristics as the acclaimed 9-3 Sports Saloon. In order to overcome the loss of rigidity caused by removing the roof, a secondary supplemental chassis was developed, effectively a ring of steel linking and reinforcing the front rear and side structures.

The result is a car devoid of the shake, rattle and roll of many convertibles. Of course, many drivers won't care a jot about chassis stiffness, but the result is a car that drives more smoothly, that allows its suspension to work properly and which also permits designers to work to fine tolerances in the construction of components like the electric folding hood.

The Saab 9-3's hood may not be of the trendy folding hard top variety, but for a ragtop it's very impressive. Electrically operated, it requires no unlatching or arcane procedures to operate, and retracts in just 20 seconds, making it possible to drop the top at traffic lights without the potential embarrassment of being caught at half mast when the lights turn green. The hood's operation is very slick indeed. Instead of flipping up, an aluminium tonneau cover raises itself and then slides back, making for a quicker operation and a better seal than a traditional hinged cover. It can also be operated while the car is moving at up to 20 miles per hour.

Saab's CargoSET system is another innovation of which the Swedes seem proud. This 'self expanding trunk' frees up a useful amount of luggage space in the boot - the kind of space that convertible owners in this class must usually forgo. The hood itself is triple skinned for improved noise and thermal insulation and is available in black, sand or blue. In order to counter the dinginess that most convertibles suffer from when the hood's up, the Saab's hood is internally trimmed in either beige or light grey.

The attention to detail is laudable. A small gutter has been sewn into the side of the fabric to prevent water droplets dripping onto the seats and there's also what Saab calls a 'surround trim'. This is basically a horseshoe-shaped line that runs from the base of each door pillar and incorporates the panels on top of the doors, the rear side trims and most of the tonneau cover. It's finished in a crackle matt black paint but can also be specified in body colour. It's a neat design idea that works particularly well with brighter colours.

The 9-3 Convertible has consistently been one of the stronger-selling premium four-seater drop tops on the market. Endowed with these fine diesel powerplants, the likes of BMW, Volvo and Audi will only have an even tougher nut to crack.