Tuning topics

Rallycrossing a 4WD DAF

It seems that there are only two branches of our sport that offer a good chance of winning with 4WD, namely hilIclimbing and rallycross. After the failure of such systems to provide a competitive edge in Formula One, the principle of having four driven wheels seems to have fallen by the wayside in single-seater racing in favour of ever more sophisticated tyre and aerodynamic aids. Perhaps it is not fair to completely dismiss the idea though, for there was that wet 1971 Zandvoort when David Walker picked off many of the conventional cars in the Lotus 56 turbine 4WD, before succumbing to the safety fencing. Also there is the thought that 4WD might yet gain the chance to prove itself if the Firestone withdrawal proves permanent and Goodyear cannot cope with demand, and Dunlop do not return.

Whereas 4WD hasn't proved the ultimate answer in hillclimbing, for there are still plenty of 2WD exponents like Sir Nicholas Williamson capable of winning the Shell RAC Championship, 4WD cars from Ford, British Leyland and DAF have all been winners in rallycross, leaving conventional cars far behind in the process. On the hills Williamson has taken advantage of a nimble March 722 and 2-litres of alloy block Ford BDA power (engineered by Brian Bart at Harlow) to put devices like David Hepworth's 5.0-litre Chevrolet 4WD behind him.

British Leyland were in at the beginning of the 4WD fashion in rallycross, during the 1968/9 season, when Brian Culcheth appeared at Lydden Hill in a Triumph 1300 and pulverised everybody in the snow. That racing Spitfire engined Triumph had been lurking at the factory for some time even then, its first public appearances put in at the BBC televised Autopoints of the mid 60s. The front end of the 1300 was very much as the maker intended, but to take the drive to the rear end this engineering feasibility project made great use of Triumph 2000 parts, including that model's gearbox, rear suspension and final drive. Utilising twin Weber 45 DCOE carburetters Triumph reckoned to have 105 b.h.p. from the 1,296 c.c. sports car engine. At the same time—coinciding neatly with the introduction just as they had done with the Escort—Ford were winning in the frozen North with a Capri. Boreham had inveigled 160 b.h.p. from a V6 power unit hitched up to the Ferguson 4WD system that the police have been assessing for some time on Ford products. The Ford and the Triumph never met, Ford running in front of lTV cameras at Croft, near Darlington, whilst the Triumph stayed in Kent for BBC's rallycross series in association with WD & HO Wills.

For the 1970/71 rallycross series Ford really thought big. By the end of the season they had three 4WD Capris, all with over 200 b.h.p. to push through the Ferguson system, backed by a works Escort, just in case things didn't work out well. In fact, at Cadwell Park in Lincolnshire things did work out well and the Capris walked their way to unopposed 1-2-3 victory in a Castrol-backed Championship. The winning Capris were driven by Roger Clark (the most powerful at 236 b.h.p. with Lucas "Can-Am" fuel injection stacks), his brother Stan, and Rod Chapman. However at Lydden the same team and drivers found a 5 second penalty start to overcome and British Leyland privateer Hugh Wheldon took his conventional Mini 1,293 c.c. Cooper S to his second BBC/Wills title victory. In the last round of that series a 4WD factory Mini 1,293 S also appeared for the first time and gave the big Capris a whipping, but with the withdrawal of the BBC from Lydden, and the absence of works Ford effort in 1971/72, BL were saved the expense of building up a team of such efficient devices.

Meanwhile, in the opening months of 1971, the DAF competition department personnel from Eindhoven had already been involved in British rallycross for several months, using Renault engines in the Variomatic transmission 55 coupés. The results with former motorcycle scramble champion Jan de Rooy driving were excellent in the works filled fields of those days. Excellent that is by the standards of a front engine rear wheel drive 1300, a place just inside the top ten being the best they could attain. Returning to Holland after a December rallycross weekend, DAF's chief transmission engineer Wim Hendreks and de Rooy started talking about the performance of the 4WD Capris. Naturally their thoughts then progressed to "why not a 4WD DAF?"

Less than three weeks later the cigarette packet scribblings were incorporated in one of the existing conventional cars, converted for its new role at the de Rooy's haulage business in Eindhoven . . . I say de Rooys because Jan's brother Harry became ever more heavily involved in his brother's sporting interests, driving regularly in a second worksbacked car to this day. That car, which I was lucky enough to go and see as soon as construction had been finished because DAF have a very helpful public relations officer in John Springate, was the same basic bodyshell and running gear as I was able to try at Lydden on Bank Holiday Monday, 1972, by which time it had competed in innumerable British and continental rallycrosses during its two-year life.

Although, from the hump in the roof for the driver's head down to its Michelin racing tyres, the DAF hybrid looked much the same, there have been important changes since that first prototype. The original Renault engine, modified to give 128 b.h.p. by Bernard Collomb of Nice, was replaced in 1971 by a Lotus Ford Twin Cam. This engine was also tuned, in this case by BRM To Phase 4 specification, and raced by John Gillmeister before it was sold, via Ford backed fellow rallycrosser John Taylor, to DAF. In its new home the Twin Cam, which is mounted transversely where the front seat would normally be and drives to a Variomatic also arranged transversely in the front seat area, has performed very reliably. Peak power is estimated at 175 b.h.p., this peak reached at the 7,500 r.p.m. which the Variomatic tends to hold the engine at under full throttle conditions. Currently the DAFs, run as the Camel-DAF racing team and decorated in that cigarette company's bright yellow, consist of three cars for Jan and Harry de Rooy to choose from. The latest pair of cars have front mounted Ford BDA 16-valve power units modified by David Wood Engineering in Mildenhall, Suffolk, to give around 200 b.h.p. The later cars are heavier than the "bump roof" original but they still have the Variomatic mounted in the passenger area and are easily switched from 4WD to 2WD wherever organiser's penalties are severe for 4WD.

The Variomatic has no reduction gears on the original DAF 4WD, transmitting power via standard secondary pulleys to separate propshafts running fore and aft to BMW 2002 differentials with limited slip control. Front driveshafts, Macpherson struts, hubs were from a Taunus 12M while the all disc braking came from a Renault Gordini. The rear suspension is based on that used by the company's prototype rallying 555 coupé, a De Dion axle sprung by leaves; both front and rear suspension are restrained by anti-roll bars. Minilite wheels normally wear dry weather racing tyres, but for our non-competitive runs heavily grooved wet weather Michelins of 13 inch diameter rested on the 7 inch rims.

Fred Hagendoorn, the bespectacled former assistant to Rob Koch, is in his mid twenties and now manages DAF's competition activities as Koch has returned to the sales department. As usual he was on hand to see his cars run and to keep an eye on the back-up car whilst and another scribe had fun in it.

Once installed another obvious individual trait of the car is apparent: the steering wheel is in the middle and one has to straddle the old propshaft tunnel to operate the brake, with a throttle on the righthand side, that's to say on the engine side—we're sitting above the transmission! To connect the steering column up to the standard rack and pinion the constructors took the easy way out—a chain, though one would never know from the steering action, which betray's no sign of this unorthodox link.

The car was fairly hot from a previous thrashing so I was advised to do no more than 5 laps—the car would normally cover only three in competition, so I had to keep a close eye on the water and oil temperatures. Gauges are also provided for engine r.p.m., ammeter, oil pressure and fuel contents, but I found that I needed to slow up on straights to read any of them, underlying (together with just a stop and go pedal) that in this form of competition you just get on with it and leave the engineers to read the dials before and after!

The getaway from a standing start was certainly very different to anything I've experienced before: just a feeling that one was encased within a catapult which had just been released. Once the throttle is depressed the engine note just goes up slightly with hills and whilst combating loose surfaces. For my trial the normal Lydden summer rallycross course was used, in a very dry and dusty state. The speed at which the car could enter the notorious chalk section was quite astounding, this smooth loose surface allowing one to set the car up just on the throttle. The flat out ride—across the bumpy meadow was encompassed in limousine comfort and choking clouds of dust, which promptly caught one at the Devil's Elbow hairpin, just after the tarmac track was encountered.

After the ease of control on grass and cinders, it was a rude shock to fight the heavy steering on the tarmac sections. If this problem was magnified in F1 cars with their "dolly" steering wheels and super wide rubberwear, I can quite see why McLaren, Matra and Lotus gave the idea up. Definitely a Tarzan task.

At Lydden there is another sharp righthander at the top of the hill, then a dreadful plunge onto comparatively smooth track into what used to be called the Cinders; nowadays this section is much smoother and seems predominantly covered in chalk as well. The right-hand hairpin calls for a lot of braking and understeer lock on the way in, but a quick flick out to the grassy kerb seems to set the car up straight for the downhill run. Whereas the car has probably been under 70 m.p.h. to this point, down that hill it seems to get up to 90 and the cinders/chalk righthander looms forbiddingly. With brakes and some power applied simultaneously the yellow DAF rockets onto the rough with joy. Even full throttle only produces mild tail out at my pace, and the left and right flick to complete a lap on the rough merely reinforce my new enthusiasm for 4WD.

By the time I take the car back to make way for the proper racers the way to 4WD round corners in comfort has become clear—apply dabs of power to lighten the steering. Naturally that is no advice for a competition driver and that may be why Roger Clark so obviously disliked the Capri 4WD, for any such layout can give you understeer when a rallyman's natural inclination is toward sticking the tail out as far as possible without revolving.

While Haggendoorn was timing practice for the rallycross I saw the advantages that 4WD can give, even on a dry day. The two works cars, identical save one had 4WD engaged whilst the other did not, were nearly 3 seconds apart with the 4WD ahead and the two brothers are reputed to be within tenths of a second of each other in terms of potential times. In fact my own time was reputedly faster than the 2WD competitors, but that was not official! In the afternoon's sport the 4WD went on proving the point with 2.6s quicker than the winner, Taylor in his immaculate Escort RS 1600. Taylor still won of course because of the 5 second penalty (a fair and reasonable equaliser I think when you think how much the 4WD system costs) but I think the DAFs score a technical moral victory for efficiency, plus some useful Variomatic development work. — J. W.