The car was originally built by Geartronics director, Neil Wallace, back in 1988. Starting life originally as a Talbot Sunbeam 1.6GL, now the only parts that have remained standard are the light units and a few bits of trim!
The first rally outing for the car and driver was the 1989 "Carrac Bevmag stages" at Manby airfield in Lincolnshire. Incidentally, the event was won by a certain Johnny Milner driving a Peugeot 205 in what was his first rally event! For the first few years of competition the car remained fairly low-tech, sticking to the modifications that the 'works' teams used in the early eighties. This kept the car ultra reliable if a little slow and un-competitive. The original pushrod 1600cc engine was retained and at the height of development managed a realistic 130bhp at best.
The picture on the left shows the rollcage installation. After a serious accident in 2000 in which the crew were lucky to escape uninjured, it was decided to install a 'proper' rollcage along the lines of the latest WRC cars.
While not using the exotic and prohibitively expensive materials of the works teams, the rollcage is welded into the bodyshell at numerous points and includes triangulation members to substantially increase the rigidity of the 'shell. If you would like a cage of this quality you could do a lot worse than to contact Richard Lepley at
Prepfab Motorsport.
Like all aspects of Geartronics work, the preparation of the engine is done to the very highest standards. When assembling a high performance race engine it is critically important to maintain almost clinical cleanliness. The slightest spec of dirt can in some cases lead to reduced engine life or in extreme cases, catastrophic engine failure! The engine fitted to the Geartronics car is based on the Vauxhall 2 litre 'XE' 16 valve. However, whereas the standard engine produces in the region of 150bhp @ 6000rpm the race engine produces around 230bhp at some 7500rpm and can safely rev to 9000 - a speed at which the standard engine could never reach under its own steam and would probably disintegrate if it could!
To achieve power outputs of this level requires a great deal of modification to both the internal & external components of the engine. Forget bolting on a fancy air filter and a 'big bore' exhaust, this will do practically nothing to increase performance but plenty to annoy other motorists! Forget also the highly dubious figures from some tuners who claim in excess of 200bhp just by fitting fuel injection throttle bodies to an otherwise standard engine.
To produce much in excess of 200bhp requires engine speeds to increase well beyond the 6000rpm of the standard engine and to do this the standard camshafts will certainly not do. Because of the increased engine speeds required to produce the higher power, special pistons, crankshaft, connecting rods, flywheel etc have to be used to cope with the dramatically increased stresses that come with this higher speed.
The photograph on the left shows a view of the passenger compartment, obviously. As can be seen, it is far removed from an everyday road car. Anything that is not required is removed to save weight and there are numerous safety features installed, most notably the internal rollcage, seats and 3" wide 6 point harnesses. Other safety items visible in the picture are the fire extinguisher in the passenger footwell and the battery isolation switch in front of the gear lever. There is also another fire extinguisher behind the seats which is plumbed into the passenger compartment and engine bay, this can be triggered by either of the crew or externally by marshall's in the event of an accident.
Just as important as making the car fast, it is vital that the car is able to corner and stop effectively. To this end, special brake and suspension components must be used. The Geartronics car uses many unique and purpose designed suspension components in an effort to maintain optimum suspension geometry at all times. All the rubber suspension joints of the standard car are replaced by spherical bearings and existing balljoints are replaced with larger & stronger items. The braking system uses discs all round which are considerably larger than standard, the ventilated fronts are gripped by large 4 piston aluminium calipers which help dissipate the heat generated by sustained heavy braking.
The transmission system of the Geartronics Sunbeam is pretty conventional but utilises some fairly high tech components, most notably the 6 speed sequential gearbox. Engine power is transmitted to the gearbox via a 'lug drive' twin plate ceremetallic clutch. Drive from the gearbox is then taken by a single piece propshaft to the live rear axle.
The axle is '5 linked', in other words there are 4 fore & aft links and a transverse panhard rod for lateral location.
Now here comes the trick part of the system because the gearbox is interfaced to The Geartronics control ECU. A sensor on the gearstick detects an imminent Gear change.
On receiving this signal, the Geartronics Flatshift ECU momentarily turns off the engine, thus removing power from the gears. Because the gearbox uses dog engagement instead of syncromesh, extremely rapid up-shifts can be made without use of the clutch or lifting off the throttle! This maximises power delivery to the road and helps keep the car balanced due to the fact that power is only lost momentarily - it also sounds superb!