Pirate DJ

by Simon McBeath

(From Racecar Magazine Vol 9 No. 5)

There are many precedents of audacious new constructors taking on more numerous, established names in a wide range of categories, not all of which turn out as success stories. Based in premises totaling 6000 square feet (558 square metres) in a converted 18th century cotton mill on the edge of the UK's scenic Derbyshire Peak District, new kid on the block DJ Racecars can, however, already boast some notable successes in hillclimb, sprint and circuit racing events in its fledgling career. Entering its second year, the company is now set to take its DJ ADS 1 single seaters onto the highly competitive mainstream UK hillclimb scene, where they will come head to head with the Jedi and OMS swarms, as well as contesting national sprint rounds. Furthermore, subject to a successful conclusion in current negotiations, the DJ ADS 1 will also be eligible to run in the UK Monoposto Racing Club's Championship. Three cars will be competing in 1999.

ADS-1 single seaters pictured near the company's base in the Peak District

Del Quigley, a time served engineer and former autograss constructor/competitor, is the boss, driving force and chief engineer of DJ Racecars (incorporating his first company, DJ Engineering, set up in 1996) and is assisted presently by one full time employee, Chris Rigby, an ex-rally and speed event driver, who performs the dual roles of race engineer and car builder. In addition, the DJ ADS's designer, Andy Smith holds down a full time job elsewhere in aerospace engineering and works part time, voluntarily, at DJ (just 7pm to midnight most nights..), also assisting with machining. Del's partner Liz Hallworth keeps the administration and accounts on track. DJ maintains the normal fabrication and machining facilities of any small racecar constructor, including a 3070 by 1220 mm (121 by 48 inch) T-slot surface plate, welding equipment, a sizable lathe, a mill, and a sturdy pillar drill. In addition, a self-constructed oven with vacuum attachments enable pre-preg carbon fibre reinforced composite components to be moulded, and DJ is now producing a range of carbon fibre aerofoils at spans up to 1700 mm (67 inches).

Loading the top half of an aerofoil secondary element for curing

But the company's pride and joy is a substantial Societé Genevoise CNC 3 axis machining centre, large enough to deal with body bucks and engine blocks, and accurate enough to manufacture high precision components. DJ's aluminum wing moulds were made on this machine to tool paths derived from 2D CAD profiles (with assistance from Del's brother Andrew's company Vetech Engineering, co-founded by Del and designer Andy Smith in 1994, which has Parametric Technology's renowned Pro Engineer 3D CAD/CAE software package at its disposal).The first thing that strikes the observer of the DJ ADS 1 car is that this is no cut down racer. The wheelbase of the tubular spaceframe chassis car is 95 inches (2410 mm), and track measurements are 59.8 inches (1520 mm) front and 56.9 inches (1445mm) rear. Overall the car is fully 10 inches (254 mm) longer and 6.5 inches (165mm) wider than a Jedi. The CAD designed triangulated chassis comprises mostly 1 inch (25mm) square section steel tube of 16 and 18 swg (1.6 and 1.22 mm) wall thickness, with twin 1 inch (25mm) T45 alloy steel roll over hoops behind the driver, braced fore and aft, and a single dash hoop. The chassis is paneled with sheet aluminum skins. Aluminum honeycomb paneling will be available on the DJ ADS 3, a variant in build at the time of writing, which will also have a single 2 inch (50 mm) roll over hoop.

The ADS-1 is uncomplicated and highly effective

The engine currently used is the Suzuki GSX-R 1100 WP water cooled in line four 16 valve 1074 cc unit, with integral five speed transmission. Supplied in lightly modified "standard" tune, with Dynajet kit, K & N air filters and a Dyna 2000 Electronic ignition system, the TTS Performance Engineering prepared engines turn out around 125 bhp at the rear wheels at 10,500rpm. A more highly tuned engine has now been supplied for the "works" car by driver Mark Budgett which develops 155 bhp at the wheels (approximating to 180 bhp at the flywheel) at 10,500 rpm, and torque of 75 to 83 lb.ft between 7000 and 10500 rpm. Customers may specify their desired engine tune state. The integral five speed constant mesh transmission has the usual motorbike derived mechanically operated sequential type gearchange pattern of "one down, four up". The company has also successfully experimented with a pneumatic steering wheel mounted paddle operated gearchange with electronically controlled powershift capability, and development work on this project is ongoing. Drive is transferred by a 530 type O-ring chain, and chain tension is cleverly preserved by a DJ designed and manufactured elliptical, infinitely adjustable differential carrier. The limited slip differential is a Quaife torque biasing unit, whilst split alloy rear sprockets enable rapid final drive ratio changes.

The DJ-manufactured differential carrier incorporates an elliptical chain adjustment and clamping system

Driveshafts are GKN manufactured in high tensile steel, and driveshaft joints are 93.9mm (3.7 inch) outside diameter six hole GKN CVs. The suspension geometry was derived with computer aid, whilst its execution incorporates a blend of current and traditional methods. Front suspension is by unequal length, asymmetric wishbones, whilst pushrod actuated steel fabricated bellcranks operate the coaxial spring/Avo adjustable damper units. Uprights are fabricated mild steel, and Ford wheel bearings are employed. Rear suspension is by an upper forward angled transverse link and radius rod, and lower reverse wishbone with radius rod. Pushrods and offset fabricated bellcranks operate the rear spring/dampers, and the triangular uprights are again in fabricated mild steel. All the suspension links are manufactured in high tensile steel. Springs are 450 lb/inch (79 N/mm) all round, though the wheel to damper motion ratios differ front to rear. Presently no anti-roll bars are fitted, and although body roll is apparent, the DJ ADS is reportedly very easy on tyres, and this enables the softest compound available to be run. However, anti-roll bars to permit driver adjustability of handling characteristics are an option. Steering is by Titan rack and pinion. The Image three piece wheels are 8 inch (203 mm) front and 10 inch (254 mm) rear, and can be supplied with four bolt Ford PCD or centrelock hubs.

For hillclimbs and sprints Avon cross ply tyres of  7.0/21.0-13 and 9.2/22.0-13 sizes are utilised, whilst for circuit racing, Dunlop are providing 170/510-13 and 210/570-13 radials. Braking is by 10 inch (254 mm) Audi-derived discs all round, skimmed to 6 mm thickness and cross drilled, whilst Willwood Engineering calipers are four piston at the front and two piston at the rear, clamping Mintex friction material. A mechanical brake bias adjuster is fitted as standard, although development work has gone into an electrically adjustable version. Hydraulic proportioning valves are another option. All lines are "aeroquipped". Bodywork is supplied in either carbon fibre or glass fibre reinforced plastic panels, and is in five main sections; the nose/cockpit cover, the engine cover, the sidepods and the rear undertray/diffuser. Simple aluminum aerofoils were fitted at the time of Racecar's visit, though needless to say, in-house manufactured carbon items, of twin element configuration, that exploit the dimensional freedom of the hillclimb and sprint regulations (up to 1500 mm, or 59 inch overall width at the front, up to 1400 mm, or 55 inch span at the rear) are on the job list. For circuit use the rear wing will be restricted to a maximum 900 mm (35.4 inch) span. The wide diffuser tunnels start their relatively shallow divergence well forward, approximately in line with the centre of gravity of the car with driver aboard and, when first fitted, apparently necessitated an increase in spring rate to prevent the chassis from grounding under the influence of the additional downforce generated In the cockpit, the driver is held in the moulded GFRP seat by a six point TRS harness. Ahead is the rather spartan dash, with just a water temperature gauge, switches, warning lights and fire extinguisher trigger fitted, though customer cars have a rev counter fitted as standard. A shift light is set into the lip of the cockpit surround above the Mountney steering wheel. The gearshift is on the left hand side, and beneath the driver's legs is the 2.25 litre MisTec fire extinguisher, compulsory only for circuit racing in the UK, and usually removed for hillclimbs and sprints. The fuel tank is located behind the seat; a 19.5 litre capacity tank is used for racing, but is replaced with an 8.8 litre one for the shorter "speed" events. 

The DJ ADS 1 would seem to have a number of characteristics that have contributed to its impressive pace to date, principal among which must be its relatively long wheelbase and wide track for a car weighing in at just 320 kg (704 LB) excluding pilot. And works driver Mark Budgett attests to the confidence inspiring poise and balance of the chassis when driven hard, factors which help to explain the car's ability to defeat a methanol fueled 3.5 litre Judd V8 engined Pilbeam at a wet sprint in its first event of 1999. The car achieved similar giant killing feats during 1998, when in its first season, and running a standard specification engine, highlights included one outright course record, two Fastest Times of the Day (FTDs), winning at its first event, and taking third place overall in a British Sprint Championship Run Off against the regular large capacity single seaters. DJ is now designing a two seater sports racing car, the DJ ADS 2, employing the same suspension geometry as the single seater, which should be a competitive contender in the new British Open Sports Car Championship, given the power to weight formula that the category is employing. If it follows the pattern established by its progenitor, it could well ruffle some feathers on occasions...