Meanwhile, the five-door hatch and Sports Tourer estate will get some cosmetic changes and will feature in a revised Astra range that arrives in dealers this September. Badged 2.0 CDTi BiTurbo, the new engine is also likely to spread to the other bodystyles in the range, although Vauxhall won’t yet confirm that.
The twin-turbo-diesel for the GTC is borrowed from the Insignia, where its blend of power and fuel economy make it one of Vauxhall’s best diesels.
In the GTC it makes 192bhp and 295lb ft of torque and boasts a top speed of 139mph and a 0-60 of 7.8sec, which make it the fastest diesel in the GTC range and comparable to many rivals’ turbocharged petrol models. The other important figures are 139g/km of tailpipe carbon and 53.3mpg fuel consumption.
Badged 2.0 CDTi BiTurbo, the new diesel features sequential turbos with the smaller blower spinning-up rapidly and providing up to 258lbft of torque form 1500rpm. The second, bigger turbo starts working in the mid range, from 1750rpm to 2500rpm, adding an extra 37lbft.
To cope with the extra performance the GTC Bi Turbo also gets a 6mm lower chassis and 18in wheels. Also on the standard equipment list are a body-kit, electronic climate control and ‘Track’ interior trim.
The GTC BiTurbo is priced from £23,925, a £995 premium over the 163bhp 2.0-litre diesel.
A package of mild cosmetic tweaks will distinguish the Astra from the autumn with a new front grille, restyled bumper and new front indicator lamps. The rear is tweaked, too, with a new boot panel and chrome-trim added to the lower bumper moulding.
The other improvement to the Astra is a longer list of optional equipment, much of it available on the Insignia and now brought to the Astra. Included on the list are front and rear camera systems that can read speed limit signs and provide collision warnings. Some of this equipment is included in a £750 Driver Assistance Pack.