Time and years have caught up with us, and unfortunately age and health issues have now curtailed our activities in speed events. Both Andy Fraser and myself have enjoyed a brilliant time together competing, now for a period of over 50 years.
Our most recent project up until the end of 2022 was the Aston Martin Vantage GT4 lightweight hillclimb car. This was constructed over a period of three years, starting with a Prodrive prepared chassis complete with FIA approved roll cage, and built with the precept of keeping everything as light as possible by using carbon fibre composites and utilising aluminium in place of steel components where possible without causing detriment to safety or reliability.
The finished car ready for it’s first shakedown run at Shelsley Walsh July 2020.
This new car superseded the Red Prodrive GT4 car that we drove for four years. It is also based on a 2016 Prodrive GT4 VH (verticle/horizontal) platform of bonded and riveted aluminium sections and castings to create a very rigid and strong chassis.
Built from the ground up by both drivers and engineered specifically with speed hillclimbing in mind, a great deal of time and effort was spent by us on reducing the weight of the car. This was achieved by replacing the standard doors, bonnet and rear hatch with carbon fibre panels, as well as many of the incidental components. A lot of heavy or steel components and brackets were been replaced or re-machined from aluminium or lightweight materials. To give you some idea of the weight saving, the Prodrive GT4 car was specified as 300kgs lighter than the road car. This car is 100kgs lighter again.
SPECIFICATIONS
Engine: Aston Martin N24 4300cc V8
Engine Management: Motec M150 ECU with Launch and Traction Control, complete with C125 Dash Manager and Data Logging
Power: Adequate – Our experience shows that exceptionally high HP and torque figures can be obtained, but are dependant on the choice of Rolling Road Dyno coupled with the amount of money you wish to spend!
Clutch: Twin Plate cera-metallic with lightweight flywheel.
Transmission: 6 Speed rear mounted gearbox/transaxle with central mounted sequential shift with Hewland straight cut gears. For 2021 this system was modified to a pneumatically operated paddle shift.
Exhaust: Silenced Stainless Steel system with race spec catalyctic converters and manufactured by RS Fabrications.
Suspension: Double wishbone spherical bearing suspension front and rear suspension and adjustable for toe, caster and camber. 2 way adjustable Bilstein dampers with coil springs.
Brakes: Brembo Front – 380mm diam ventilated steel rotors with 6 pot calipers. Rear – 330mm diam ventilated steel rotors with 4 pot calipers – Pagid brake pads.
ABS: Bosch M4 driver adjustable motorsport system.
Safety: Prodrive FIA approved 10 mounting point roll cage. Carbon drivers seat fitted with Schroth Racing six point safety harness.
Wheels: Magnesium 5-stud GT4 Wheels – 10×18″ Front and 11×18″ Rear.
Tyres: Avon Hillclimb slicks and Michelin Wet weather tyres.
Aero Devices: Increased protrusion Carbon front splitter with front dive planes, rear diffuser and rear hatch mounted adjustable wing.
These three pics show how we started with a bare Prodrive GT4 Chassis.
This FIA approved rollcage produced in-house at Prodrive is a work of art.
The engine is an Aston Martin 4.3 N24 V8 unit,previously used by the Aston Martin factory team to compete in a 24 hour race at the Nurburgring.
This view is from the lightened flywheel end with a twin plate racing clutch. The driveability of this setup proved to be excellent, with the bonus of smooth power take up. This was a bonus when manoeuvering around the paddock, unlike our previous Porsche GT3 cup car, which was like a bucking bronco!
The engine installed in the front subframe.
This pic shows the engine installed with front suspension in place – we finally used Brembo high spec endurance brakes.
Side view of the front suspension and brakes – the spring and damper units were eventually replaced with Bilstein units as they proved so successful on our previous GT4
The rear suspension and brakes.
We are slowly getting there!
This pic shows the rear end. It is parked next to our Prodrive GT4, which we used for four seasons – 2016 to 2019.
The cockpit during construction. The dash shown was eventually replaced with a superb lightweight carbon dash. This picture also shows the centre mounted sequential gear shift, which was used for the few meetings we used for shakedown during 2020. The gearshift system has been changed to paddleshift for 2021.
An example of our machining prowess, showing the top suspension mounts machined from aluminium. The one on the RH side is from the Prodrive GT4 and was used as a pattern to replicate the other four.
A further example from our machine shop. This is the twin cylinder adjustable brake bias setup. There were a few modifications made during the process of prototype to finished article!
The engine bay with all the most important items in place. A lot of midnight oil spent!
The finished car ready for graphics to be applied.
Check out the rear wing and diffuser out. Adrian Newey eat your heart out!
The car still on the ramp awaiting the final inspection.
The graphics all now finished.
Raring to go! (sic)
Shed Motorsport 