Emphasis on sports cars—road impressions of the works Mk. IX Lotus
There is no need to underline the excellent performance, one might write “circuit-performance,” of Colin Chapman’s Mk. IX aerodynamic Lotus, for its race successes at various club meetings and its splendid showing, while it was running, at Le Mans and in the T.T., speak nearly as loudly as the little car’s exhaust note! Moreover, enthusiasts who went to last year’s Earls Court Motor Show were able to examine the appetising components which Chapman offers to “specials”-builders on his stand in the main hall—such covetable fare as divided-axle i.f.s., de Dion back-end, a lightweight tubular space-frame with low-drag radiator and other factors enabling it to wear a two-seater sports body of reasonable aerodynamic form.
I write of this Lotus in the singular because this article is concerned with the actual Le Mans/T.T. car, Mk. IX/87, which is the property of Peter Jopp and is driven in races by its designer/creator, Colin Chapman. In fact, of course, the small firm of Lotus Engineering Ltd. at 7, Tottenham Lane, Hornsey, London, N.8, has been “mass-producing” these advanced little cars for some time—”mass-producing,” that is, for a concern of this modest size, making what are essentially specialised sports/racing cars—Lotus supply the chassis frame and components in various combinations at prices which they will quote gladly if you apply to them.
This particular Lotus, when Motor Sport had it for test in November, had led a particularly hard life. Apart from doing a very appreciable proportion of Le Mans and the T.T.—at Le Mans the car was disqualified and in the T.T. it was leading on Index of Performance until an oil-pipe broke, causing it to lose the 1,100-c.c. class to a Cooper-Climax by a mere five seconds—it had been driven in various lesser races and used by two other motor journals for assessment purposes, besides which, on November 16th, just before we went to Hornsey to take it over, XPE 6 had been tried out at Brands Hatch circuit by a dozen different drivers, who collectively drove it at racing speed for more than 240 laps (or over 300 miles), six of them unofficially approaching or equalling the absolute sportscar lap record for this course. Reg. Bicknell clocked 61.2 sec., Alan Brown 61.6, Ivor Bueb and Graham Hill both got round in 61.7, George Wicken recorded 62.8 and Dennis Taylor 62.9 sec., while Ken Tyrrell, D. Boshier-Jones, F. Hobart-Smith, John Brown and Chapman himself all “had a go,” the last-named modestly refraining from quoting his lap times. And all this without a proper overhaul since it was registered early in June.
Not surprisingly, after such high-speed usage, the Lotus was becoming rather weary during our spell with it, and we experienced a few minor bothers, such as a “flat” battery due to a “shorting” electrical lead, a flat tyre, failure of the rev.-counter drive (which mystified us for a time by rotating its drive-gearbox until the latter chafed against the base of the distributor, cutting out the ignition), and breakage of a dynamo support bracket. It takes more than this to mar the joy of driving a Lotus and, anyway, the car wasn’t built to run in a Mille Miglia and is probably more at home going to Silverstone or Brands Hatch in a van, accompanied by a plentiful supply of tools, than being put to work as a long-distance road-express.
Certainly this low, tail-finned two-seater places emphasis on “racing” rather than “sports” and is today’s equivalent of the Grand Prix Bugatti or Amilcar Six of earlier times—so that lack of a spare wheel, an exhaust note more obvious than that of a Grand Prix car, and a driving position calling for helmet and goggles, are all part of the fun.
The battery is a small 12-volt affair, sharing the tail with a six-gallon fuel tank which would have to be removed to extract it, the snap-action filler of this tank had to be wired down, no speedometer graces the dash, and for the benefit of those who have never examined a Lotus I add that before the single headlamp could he used the bonnet panel had to be lifted and the lamp prised upwards into the night; obviously, there were no hood or sidescreens!
Yet if these remarks paint the T.T. Lotus as a stark sports/racing car, as you would doubtless expect it to be, the Coventry-Climax engine is happily devoid of temperament, whether poodling through towns or shooting the car up to 85 m.p.h. along the meanest straights, the Lodge HLNP plugs uncomplaining, consuming normal Esso Extra petrol, lubricating itself with Essolube 30 and, incidentally, remaining commendably free from oil leaks. Moreover, with the not-unduly-fierce camshaft which produces 81 b.h.p. at 6,700 r.p.m. on a compression ratio of 9.5 to 1, this clever little 72.4 by 66.6-mm. (1,097 c.c.) engine proved able to run up to 7,000 r.p.m. in the indirect gears in the normal coarse of business, Harry Mundy, who had a large hand in its design, telling us that something around 400 r.p.m. beyond this wouldn’t really stress things too far. And 7,000 r.p.m. in third is equal to no less than 87 1/2 m.p.h. on the low axle ratio!
On this “sprint” ratio of 4.5 to 1 the Lotus-Climax is well able to reach 85 m.p.h. between corners on the average rolling English road, and on our test circuit, under not very favourable conditions, achieved 100 m.p.h. at the end of a stretch where far larger-engined sports cars do not often exceed this figure. Given time to work right up to it the maximum should be approx. 108 m.p.h., while with a high axle ratio (3.9 to 1) installed, speeds in the region of 130 m.p.h. are encompassed.
The handling qualities of the car are interesting. The driving position suits persons of medium height, although even then the pedals seem rather distant and not amenable to easy heel-and-toe gear changes. The position is essentially arms-straight to the pleasing (if slippery) three-spoke, 15-in., leather-rimmed steering wheel and, as has been hinted at, a gale of wind sweeps round the driver’s head, although the flatter screen before the passenger gives him or her quite good protection.
On first acquaintance there are two surprises. First, the comparatively hard suspension; secondly, the high-geared steering. The former intrudes only over bad surfaces taken at modest speeds i.e., up to 65/70 m.p.h.; above this speed the ride smooths out and bad roads have less effect on the car. The Lotus rack-and-pinion steering, however, is geared like that of a “chain-gang” Frazer-Nash, asking barely 1 3/4 turns lock-to-lock, with a reasonable turning circle. The result is that in cornering the wheel is scarcely moved and certainly it is impossible to steer into skids in the customary enthusiastic manner—just a flick and the car is under control. It is fatal to grip the wheel tightly or the Lotus proceeds in a series of swerves, yet kick-back from the divided-axle i.f.s. precludes letting the wheel go free, the technique over bumps being to let the rim play through one’s fingers. Incidentally, castor-action is virtually nil.
The cornering characteristics of the Lotus-Climax are of the kind that win races. There is a tendency to understeer which never becomes embarrassing; indeed, the action is virtually neutral, while the de Dion rear-end enables the power to be turned on early out of slippery corners, for both wheels spin together and the car keeps to the intended course. If it doesn’t, the aforesaid flick of the taut yet light steering is all that is required.
Everyone who tried the Lotus was impressed with its excellent acceleration for a 1,100-c.c. machine, aided by reasonable spacing of the gear ratios in the M.G. J2 box—for want of a substitute, Chapman uses secondhand, but overhauled, M.G. J2 boxes, substituting for the cast-iron bell-housing a light-alloy one, drilled with lightening holes—what a tribute to the quality in pre-war M.G. cars! A standing-start 1/4-mile, essayed two-up, without fireworks, and without practice, occupied a mere 16 1/2 seconds. While driving over our measured 1/4 mile we took pains to check the engine/road speed relationship, 1,000 r.p.m. being equal to 15.8 m.p.h. in top gear and 12.5 m.p.h. in third gear.
The enjoyment of this excellent and progressive acceleration is somewhat marred by the force required to change gear, the remote lever being set high up, so that the action is that of lifting rather than moving from one position to the next; using strength, the swapping of cogs is a rapid action, but how tiring in a long race… The central hand-brake lever is also too long and moves through too great an arc for convenience, and it cannot be dismissed as merely a parking adjunct, for on a car which likes the revs. maintained for a brisk get-away, it is useful to approach road junctions holding the car back temporarily by hand.
The Borg and Beck racing-type clutch is either in or out and heavy to operate, but showed no general tendency to overheat, save when changing rapidly into top after 7,000 r.p.m. had registered in third gear.
The brakes—9-in. Girling disc—deserve a paragraph to themselves, for in all ordinary circumstances of fast road motoring nothing more was called for than just resting the foot on the pedal; in an emergency-stop they were of exceptional power, to wearing flats on the Dunlops on a dry road or converting the car into a toboggan in the wet! They gave a real sense of security and gain 100 per cent. full marks. Twin master-cylinders and fluid reservoirs are used, one for the front and one for the back brakes.
In appearance XPE 6 is exciting, for the well-known aerodynamic form was offset by racing number discs and night-racing recognition lamps. Of more practical interest is the extreme ease with which the body can be removed completely from the chassis. During our times of trouble we took off the one-piece bonnet, front wings and scuttle in a matter of minutes, when almost all the machinery is accessible. Genuine Dzus fasteners facilitate this useful operation. This body, which has ample accommodation laterally and fore-and-aft for two adults, is in a very thin-gauge light alloy and is the work of Williams and Pritchard.
The general specification of the Lotus-Climax Mk. IX is well known but for those who like details, let us run over the general layout and construction. The multi-tubular space-frame has swing-axle front suspension, formed from a divided Ford axle beam, liberally drilled, with long radius-arms, suspension being by coil-spring-cum-damper units. At the back similar suspension units are employed with the de Dion rear-end, where the disc brakes are mounted inboard. Centre-lock wire wheels are used, those on the car tested being shod with 4.50-15 Dunlop racing tyres at the front, 5.25-15 at the back.
Right in the nose of the car is the small ducted radiator, from which a long pipe on the near side runs to a tiny water-system header tank under the scuttle, the water return pipe leaving the back of the head on the off side, and a pump on the near-side front of the engine encouraging circulation. This pump is belt-driven in conjunction with the dynamo on the off side, which is a normal Lucas dynamo with an extension driving a Smith’s 5-in. rev.-counter reading to 8,000 r.p.m. Normal Lucas coil ignition is used, the sparking plugs being inclined in the off side of the cylinder head.
Above the radiator is a water/lubricant heat-exchanger. Two 1 1/2-in. H4 S.U. carburetters are used, which have ram-pipes projecting into an air-box on the near side of the car, and on the same side four separate exhaust pipes feed into a single larger-bore pipe which ends flush with the side of the car. The oil-filler is accessible on the off side of the engine and there is a breather in the camshaft cover adjacent to the interesting(!) Godiva emblem which forms the Coventry-Climax trademark. A Purolator oil-filter lives outside the frame behind the near-side front wheel and fuel is fed from the tail tank by a single electric petrol pump, also situated outside the engine compartment nearer the scuttle. The steering column incorporates a universal joint, voltage regulation is through the latest Lucas RB310 unit, and stop-lamps, as required for night racing, are actuated by the brake pedal.
The dash is pretty fully occupied with accommodating two fuse-boxes, aircraft-type switches for panel lighting, the triple rear lamps, the side lamps, the two retractable Lucas headlamps (only one being fitted when we had the car), the recognition lamps, ignition and fuel pump, the aforesaid rev.-counter, and three small Jaeger dials indicating water temperature (normally 65/70 deg. C.), dynamo charge, and oil pressure (normally 40 lb./sq. in.), the last-named being a combined oil pressure/water-temperature dial, with the latter function deleted. The steering-wheel spokes rather blank the essential dials. In addition, there are: a dynamo master-switch, a switch for cutting out the lamps circuit during daylight racing, a dipper for the non-existent headlamp, and a pull-out starter switch, as well as a Tapley performance meter, horn button and central mirror. Incidentally, no fuel gauge or reserve tap was fitted. The fuel range wasn’t great, but for long-distance racing an auxiliary pannier tank is carried on the near side.
The interior of the cockpit is devoid of trimmings, but the shallow seats are not uncomfortable and the driver is kept nicely in place by the propeller-shaft tunnel, which is not upholstered. In the tail, under a Dzus-fastened panel, repose the tightly-packed fuel tank and lightweight battery, and when a spare wheel has to be carried this is somehow inserted in front of them and secured by a length of rubber cord. Lift forward the wafer-thin seat squab and the mysteries of de Dion back-end and inboard disc brakes are immediately apparent!
This starkness notwithstanding, the remarkable TWA Coventry-Climax engine commenced readily and did not run-on after terminating hard spells of motoring, we never had to look at a plug, and carburation is commendably clean over the 1,000/7,000 r.p.m. speed range, the car running without snatch at the former speed in top gear, i.e., at less than 16 m.p.h., and pulling away without hesitation. Moreover, it refused to boil, even in London traffic. The useful range from the aspect of power is from about 3,000 to 6,700 r.p.m.
The splendid performance of this 1,100-c.c, sports/racing car and the excellent understeer handling which enable it to do so well in races also render it a very fast road car. In the hands of a colleague it averaged more than 63 m.p.h., two up, over 195 miles of main-road motoring with Saturday traffic to contend with, 6,700 r.p.m. being the genuine top-gear maximum along the Salisbury straights, equal to nearly 106 m.p.h. This run included averaging 68 m.p.h. between Winchester and Petersfield and 78 m.p.h. from Andover to Lobscombe Corner, which gives some idea of the potentialities of the Lotus as a road car. Moreover, at these high speeds the consumption of Esso Extra worked out at about 24 m.p.g., so that, driven more like a mere sports car, this Lotus-Climax would obviously return economy figures comparable to those expected of a small saloon. Understandably, the engine consumed a lot of oil. The weight is 9 cwt. 1 qtr. 21 lb.*, without passengers, but ready for the road with approximately two gallons of fuel.
The basic soundness of Chapman’s design and the excellence of the Coventry-Climax engine add up to a fascinating small competition car, able to challenge many machines far larger than itself.—W. B.
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*As this weight does not tally with those quoted in other reports, we would emphasise that Motor Sport always uses the same weigh-bridge—the County Council of Middlesex Public Weighbridge at Brentford.