John Welch’s Vauxhall Astra Xtrac

Filed under: Classic News |
John Welch in his Vauxhall Astra XtracAt the beginning of 1987 it became obvious that the all-conquering Xtrac Escort had reached the end of development. John and his team looked towards the introduction of the new Rallycross regulations for 1988 before deciding on the nexr car to develop and race. Count to three and that's the time it takes for John Welch's Vauxhall Astra to rocket from standstill to 60 mph and that's as fast as a current Formula 1 car! While you could be forgiven for mistaking the car for any road-going Astra GTE, Welch's Vauxhall has four-wheel drive and is powered by a 2.1-litre turbo engine producing a staggering 650bhp. And the car has no ordinary bodyshell either; the Kevlar and carbon fibre shell clothes a full spaceframe race chassis. Welch, from Hampshire, is currently campaigning this supercar in the ultra-competitive British Rallycross Championship. Backed by Vauxhall Dealer Sport, the quiet spoken John Welch is no stranger to success, having won the championship on two previous occasions. The car itself was originally built for General Motors' planned Group S 'silhouette' rally programme but had to be shelved when FISA banned this new generation of super rally cars in favour of a less rapid Group A class. But the Astra's tremendous acceleration and leech-like traction make it perfectly suited for the mud and tarmac surfaces found on rallycross circuits. The transition from rally to rallycross spec took eight months but the debit win in the BRDA National 'A' Final at Cadwell Park demonstrated that John and Xtrac got their sums right. John Welch's Vauxhall Astra XtracThe car gets its performance from a 2.1-litre four-cylinder engine that started life in a Group B Open Manta 400. That's where it started, but Welch together with Swindon Racing Engines have increased the power output from 320bhp to a massive 650bhp. The fuel injection system comes straight from an F1 engine as do the hand-made Mahle pistons, while a Garrett AiResearch TO4S turbocharger blows at 2 bar pressure through a F1 Arrows wastegate. The car's four-wheel drive system has been developed and built in the UK by Xtrac and comprises three differentials. At the front there's a conventional limited-slip diff that feeds power to the front wheels through heavy-duty Xtrac drive shafts. There are also Xtrac internals in the rear limited slip diff while the epycyclic centre differential can vary the amount of power being transferred to either front or rear wheels. But that's where the sophistication of the system begins. The Xtrac transmission can also direct the engine's torque automatically to either the front or rear wheels depending on the grip available and the turbo boost pressure. The MBE engine management system is more sophisticated than anything ever seen previously in rallycross. John WelchAnd when John Welch hits the brakes hard before pushing the Astra through a tight corner, the system can unlock the centre diff so the car will be more responsive when turning into a bend. This year, the Astra is competing in the 11-round British Rallycross Championship, which for the first time, includes a class for Vauxhall Novas. Its one of the toughest championships in motorsport, yet John Welch's determination coupled with the Astra's remarkable performance and handling, should ensure he stays among the leaders.

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