Tuning test



On the track with an Imp-powered Davrian

THIS MONTH the content of MOTOR SPORT’S tuning pages is more than usually varied, mainly because we have been fortunate of late in obtaining some particularly interesting machinery. Originally we were to try a pair of highly-modified sports cars, both capable of more than 120 m.p.h., but they were vandalised outside the Specialist Sports Car Show, so the project was temporarily dropped in order to fit in some brisk laps of our test track in Davrian Developments’ race-prepared GT (class of racing, not a bogus maker’s label) car. In addition to this item, we have also had the opportunity to put a Broadspeed-modified 1600 GT Capri through the performance testing routine. But first the Davrian.

The question most people ask to start with is “what is it?” and on being told it is a Davrian, they look just as puzzled. The man behind Davrian Developments is one Adrian Evans, a cheerful and persistent enthusiast who first thought of building a glassfibre open sports car based on Imp components during 1965. By 1968 Evans had produced a few open cars based on original plywood-constructed prototypes. At the 1969 Racing Car Show the firm displayed a fixed-top version and an experimental mid-engined machine called the Demon, which looked similar to the normal road car, though at that stage customers had the option of Ford, Rootes or BL engines. During last year the firm did very well considering its lack of capital; a small amount of club racing was undertaken in a fully-trimmed road car, which helped to attract new customers, as did the prospect of economic fuel consumption coupled to 100 m.p.h. performance from the 55 b.h.p. Imp Sport-powered cars.

Now based at Clapham, in South London, Davrian are offering two types of bodyshell to the public, one designed for racing (and weighing 81/2 cwt. when assembled in the traditionally stark manner of British Club racing), the other tipping the nearest public weighbridge at just over 10 cwt. ready for UK use. Prices depend on specification, but a complete car can be built for under £500 using the basic £350 glassfibre monocoque shell. This features built-in twin fuel tanks of 41/2 gallons each, seat and dashboard mouldings, sliding side windows with opening quarter-lights, windscreen (laminated £10 extra) and pop-up headlamps. The latter item, when supplied as part of the basic shell, comes without an operating mechanism, though either a cable or pneumatically-operated system can be fitted on visiting a Lotus dealer, or by “wire and pulley” ingenuity, a quality which we all know is one which no kit car builder should lack. Extensive use is made of polyurethane foam padding within the shell to provide an impact-resistant protection for the aluminium fuel tanks and to prevent drumming resonance.

In the sales pamphlet’s words, “body painting and finishing are required”. Braking, suspension, engine, gearbox, wheels and the rest of the paraphernalia to make a road-going car can all come from the standard Imp, though many will doubtless prefer at least to feel the benefit of wider wheels and the Sport engine. Ground clearance can be controlled by moving the shock-absorber/coil spring mounting brackets up or down on their mounting plates: the lowest figure quoted, mainly for racing, is 4 inches clearance, while the maximum is put at 61/2 inches.

Performance figures for a Davrian with well-maintained standard Imp engines are quoted as: Standard 875 c.c., top speed of 95 m.p.h. and 0-60 m.p.h. acceleration in 17 seconds; Sport, top speed of 110 m.p.h. and 0-60 times of just over 10 seconds. These are indeed impressive figures which we would like to check as soon as possible; in the meantime, though, we contented ourselves with trying the 998 c.c. racer with a real sting in its tail from a tuned unit said to give 90-95 b.h.p. The test car weighed in as a lightweight-constructed racer and still retained the low aerodynamic shape, so performance was bound to be good: Evans claims 0-60 m.p.h. at around the 71/2-second mark and a top speed of 130. After an exhilarating session lapping a private two-mile circuit we were left with little doubt that the racing Davrian would do all its creator claims. During the test we found the Davrian would leave a 155 b.h.p. rally Escort pretty convincingly and, although such an exercise is hardly conclusive proof, it did at least give us a standard by which to judge the car.

Getting in is the usual kit car chore, or delight if you have an appropriate athlete’s physique to display. Once in we were somewhat depressed at the generally “prototype” layout, but clicking down two small switches marked “On/Off” brings into life the fuel pump and ignition circuits and a stab at the tiny starter button did very little to calm the nerves because the battery was flat.

However, a push start in second gear brings a hoarse bellow from the small cannon at the rear which doubles up as an exhaust pipe. We were warned that the steering “makes one work hard”, that the tyres were “mixed compound Dunlops” and that the gear-change was of the non-synchromesh four-speed Jack Knight variety: add these unattractive features to the wet test track conditions and you can imagine that our reporter was not in the best frame of mind for testing a primitively-finished car with no side or rear windows.

The first lap was spent readjusting to double declutching throughout the gear range and getting the hang of the stiff steering. A trip to the wide open spaces of the track’s steering pad helped enormously in gauging the feel of the heavy steering and swift, when provoked, rear end breakaway. A single-seater type of leather rim steering wheel was fitted, together with the maker’s very responsive rack and pinion mechanism; these features helped correct any rear wheel sliding with the proverbial flick of the wrist.

Back on the twisty circuit we found the acceleration almost unbelievable, a spirited start in first allowing the wheels to spin so violently that the car swung gently to and fro until third gear went home. Half-way along a subsequent straight the tachometer needle indicated 7,000 r.p.m. in top gear, somewhere around the 100 m.p.h. mark, in a time of less than 25 seconds!

The standard Imp suspension components cope very well with the favourable power-to-weight ratio, so once we had overcome our dislike of the steering, any radius corner could be tackled at an invigorating pace. Accelerating hard on the exit from a bend merely kicks the tail out in a controllable manner, while the next corner loomed up at unnerving speed from our low vantage point.

The foot controls were all placed very close to each other, making it easy (inadvertently) to heel and toe when all one really wanted to do is stop, and quickly. Applying a carefully placed foot eliminates much of the problem and the stopping powers were remarkable. In this case Standard Triumph disc brakes were fitted at the front, mounted on Davrian-manufactured alloy hubs: at the rear the standard twin shoe Imp drums were used. After 20 laps or so we pulled back into the “paddock” with a real appreciation of the performance and handling. The low overall height and a very “slippery” shape seem to be effective and these points—combined with the low road weight—certainly give the sort of performance more normally associated with 300 b.h.p. sporting machines or Twin-Cam-powered Lotus Sevens.

Adrian Evans has done well in the past couple of years merely to keep his project going when spare cash has been rather short, but now he must concentrate on the finishing touches to a design which is basically good. Lotus, Marcos, and to some extent Ginetta, have all found out the hard way that a well-prepared kit car with wiring, trim and suspension mounting points, all well sorted out, is the only profitable way to survive.—J. D. W.
Test car supplied by: Davrian Developments, 63 North Street, Clapham, SW4.

Prices start at £350 for a bodyshell; thereafter cost depends on specification.