Vauxhall Astra GTC Bi-Turbo: Driven

A diesel Astra on PH? Yes really, but this one is more interesting than you may think

Biturbo: TIME called it one of the 50 worst cars of all time. But let's not be too hard on Maserati, because it's moved on. Don't let the baggage of its name tarnish what's actually a really rather decent Vauxhall Astra, either.

Three-door Astra still a handsome car

Guffaw. But while Vauxhall's Astra is not a car we generally get excited about on PH, hidden within the range is the sort of variant that, of all people, PHers may appreciate. One that, once you get over the badge baggage, reveals intriguing engineering detail you'd normally associate with premium brands, not mainstream. The inverse of that Maserati, if you like.

Such as? Well, suspension that someone's actually thought about for one. Fitted at the front is Vauxhall's HiPerStrut setup, with decoupled top mountings to separate spring and damper loads, and thus minimise torque steer, while improving steering feel. There's an aluminium strut carrier and lower control arm - aluminium suspension components are the stuff of BMWs and Porsches, surely not Vauxhalls? - and even the anti-roll bar is made from hollow-section steel. An Astra that's focused on reducing unsprung mass: well, I'll be.

Bi-Turbo sits 6mm lower than other GTCs

At the rear, OK, it's a torsion beam, but it's firmed up by a Watt's linkage (yes, that James Watt), while an Opel engineer once told me the ability to engineer the beam to different thicknesses allows the chassis guys to tune the roll-steer characteristics closely. Cleverer than it looks, then.

With a subtle 6mm taken out the ride height, and even the option of adaptive dampers, there's been more effort put into the setup of the GTC Bi-Turbo than you'd ever first think.

Of course, all GTCs get this setup. For the cooking ones, it's to allow the fitment of big wheels. For this, it's there to tame a VXR-matching 295lb ft of torque, that's yours between 1,750-2,500rpm. Even from 1,250rpm you have 236lb ft - some people use more revs than that just to pull away from the line. It also boasts 195hp (or, in respect to Watt, 145kW), which isn't far shy of what Golf GTIs used to produce.

Oh yes, it's also diesel, so does 57.7mpg, or nearly 23 miles per gallon more than the VXR. But don't skip on - thanks to those two turbos, it performs more satisfyingly than you'd ever think.

Best learn all those buttons quickly...

Key to it is the turbo response. The small one, active up to around 2,500rpm, does as you'd expect and ensures turbo lag is minimal. In practice, this doesn't simply mean there's little delay until the surge kicks in - rather, it means this is a turbo engine that feels like a big normally aspirated one. There's far greater fluidity during transients, allowing you to blend on and off the throttle with much less staccato. The instant return of surge during gearchanges is satisfying too.

Above 3,000rpm, the big turbo takes over, which ensures this low-rev punch doesn't tail off at higher revs. It means this engine has a much greater effective power band than most narrow-window diesels, which makes it surprisingly sophisticated for what is, despite its high performance aluminium pistons, fracture-split conrods, optimised cylinder head and cams plus a five-layer head gasket, still a mainstream four-pot diesel.

Two turbos give great throttle response

Even the diesel clatter is minimised at regular revs thanks to the softening effects of the turbo induction: extend it and it does start to get gravelly, but you're far better off changing up to open up your effective rev range again. All while enjoying a planted, lithe front end and a firm chassis that still has enough rough-road depth to complement the flexible engine on twisting British roads.

In short, it's an Astra with a depth of ability, rather than one with a pleasant sugar coating that quickly dissolves when you press on. Even the steering, traditionally a Vauxhall oversight, has a pleasingly sharp, natural and in-contact feel as you turn in. Again, subtleties you just don't expect.

An unexpectedly interesting car to drive then, one more satisfying than you'd ever think. And that's why we like it so: after all, who doesn't love a hidden gem?

VAUXHALL ASTRA GTC BI-TURBO
Engine: 1,956cc 4-cyl turbo
Transmission: 6-speed manual, front-wheel drive
Power (hp): 195@4,000rpm
Torque (lb ft): 295@1,750-2,500rpm
0-62mph: 7.9 seconds
Top speed: 139mph
MPG: 57.7 (NEDC combined)
CO2: 129g/km
Price: £24,175

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MrTappets

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