DTV FIRENZA TWIN CAM

VAUXHALL’S DECISION to produce the streamlined “droop snoot” version of the Firenza coupe was a courageous one at a time of fuel shortages and gloom. Today the economic shadows seem worse than ever, but Dealer Team Vauxhall preparation boss (on the rallying side) Chris Coburn decided to press ahead with an even further refined, and extra powerful, version of the Firenza.

At this year’s Racing Car Show it was announced that Coburn Improvements would market replicas of a shining black Firenza Twin Cam displayed on the stand. Since then a second car has been partially completed, but no customer cars have been made, and it seems unlikely that they ever will be, because costs have risen to the point where it’s not even clear that it would be economic to market replicas at £6,000: Coburn’s personal example, constructed with used parts that included a converted 170 b.h.p. Vauxhall 16-valve engine, is valued at £4,750.

The car evolved during casual conversation between Coburn and his rally engineer, Paul Husband, as a prestige vehicle for DTV’s activities.

The example we drove had re-trimmed seats, Weathershield metal sliding sunroof, Radiomobile four-speaker radio/tape player with electronic aerial retraction, boot-mounted tail spoiler and fire extinguisher, rear seat belts, plus a number of smaller features.

Mechanically speaking the running gear is little altered for the new engine. Chris prefers a greater degree of oversteer in his motoring than is provided in the production model, so a rear anti-roll bar (from a previous non-droop snoot model) is installed. Even sportier handling is also provided by the substitution of a high-ratio steering rack, Bilstein gas-filled shock-absorbers and 205 section Dunlop Rally Super tyres.

The modified Vauxhall engine, high performance clutch and Firenza ZF 5-speed gearbox are easy to install, though “new tubular exhaust manifolding and a slight dimple in the front bulkhead are needed,” says Chris Coburn.

For customers it would probably be easiest to install the complete Jensen-Lotus alloy engine, for the Coburn example involved some extra labour in adapting the Vauxhall block to take the Jensen-Healey head, complete with that vehicle’s camshafts and 9 : I compression ratio. Heavy duty valve springs are installed, while inlet and exhaust porting has been modified in Coburn’s workshops to improve breathing in conjunction with twin 45-mm. Dellorto twin-choke carburetters. Beneath the cylinder head the engine consists largely of Vauxhall components, though a Lucas distributor is installed at right angles to the oil pump, below the carburation.

How enthusiastic Chris is about his interpretation of the Vauxhall Firenza (which is still available to special order, though there currently seem to be few takers at £3,048) can be gauged from his comments. “My father runs one of the more exotic Porsches, and I can’t help feeling how much better value my car is! I have a considerable amount of boot space, two proper rear seats and a far more unique vehicle.”

We drove the car for less than an hour over the kind of sunlit country roads that provide a living for the fantasies of advertising, and it emerged as a very well balanced vehicle. The handling is exceptional with a very high limit of adhesion and the kind of breakaway characteristics that allow safe, enjoyable, positioning of the Vauxhall.

The gearbox suffers from that annoying “zizz” in 5th gear, but it complements the engine’s quick response with a ratio for every situation, 120 m.p.h. coming up rapidly. The combination of an excellent torque band and the superbly matched suspension and braking systems make this a terrifically enjoyable cross-country flyer, though extra sound insulation could be justifiably requested against gearbox and engine threshings.

A worthy and interesting enthusiast’s car, but I still want a Porsche!—J.W.