A change of owner for an existing Alfaholics track day/mild race Sprint GTV required us to make a full hand control conversion for disabled driver usage. In order to do this, we carried out the following works:
- Conversion from 45mm Webers onto fully programmeable electronic fuel injection
- Conversion from the original gearbox to our Alfaholics 6-speed sequential gearbox with pneumatically-operated button gearshift (left hand operated for both up & down shifts)
- Clutch modified to have automatic motor actuator unit controlled by ECU – fed with wheel speed, engine speed and throttle angle data
- Throttle converted to a steering wheel mounted pull-ring (right hand operated) with potentiometer to operate a fly-by-wire throttle actuator
- Brake actuation converted to a mechanically connected push lever mounted next to the steering wheel on the right hand side
- Steering wheel mounted windscreen wiper latching button to optimise ease of driving in wet conditions
- Source a compact titanium wheelchair which can be stored in the boot, whilst the wheels mount on specially machined spigots in the rear seat area
The resulting conversion is superb to drive, by the controls being both ergonomic and surprisingly intuitive. The clutch control ECU/motor is only used to pull away up to 10mph and to stop when speed drops below 10mph again. It does so by calculating the rate of clutch release against certain parameters such as wheel speed, engine revs and throttle load. It is happy managing the clutch slip at manoeuvering speeds as well as carrying out full-bore standing starts. During normal driving, the buttons on the steering wheel operate the pneumatic actuator on the sequential gearbox to make upshifts and downshifts. The gearbox ECU measures parameters such as gear selection shaft rotation, engine load and engine rpm in order to adjust ignition retardation to achieve the fastest possible gearshift each time a gear shift request is made – as quick as 60 milliseconds in optimum conditions! The brake modulation is superb – it isremarkable how much brake feel is retained with the hand lever conversion.
In fact, within a few miles it was possible to make all the mental adjustments to be able to drive the car with virtually all the speed and accuracy of a car with normal controls!