Sport E Sprinting - Plan B
Entry posted by johnev
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Back in July 2015 my Sport E electric Westfield was very badly damage due to a 'racing incident' at the Curborough sprint circuit. The car rolled three times and in the process ripped off or bent all four corners of the car. None of the wishbones, uprights or wheels escaped undamaged. In addition all the bodywork was broken in some way. On the face of it this was a total loss situation. However, amazingly all the electrical systems, motor and battery remained undamaged and in full working order.
Fortunately I work for Potenza Technology. We had worked on a number of Westfield related design and development projects in the past. As a result Potenza were able to find a complete set of suspension parts and enough body panels to make the rebuild possible.
The first job was to strip the car down to the chassis and check its condition. The main battery was hard mounted within the engine bay and so must have strengthened the chassis because it proved to be completely straight. On the other hand the wishbones and mounting clevises must have absorbed the crash forces. Also five suspension mounting clevises were either bent or ripped in some way and would need replacing.
So with a bit of welding and a lot of kit building and the car could be back on the road again quite soon. But here's the problem - apart from my lack of driving skill, one of the reasons the car crashed in the first place must be to do with the unusual weight distribution.
The engine bay battery weighs in at 160Kg. The motor, power controller, battery charger and cooling system were all mounted behind the rear bulkhead. Thus about 100Kg of weight was carried mostly behind and above the rear axle line. This weighty rear end made the car over steer and I found it quite difficult to control.
Plan B.
The original car carried batteries in both the engine bay and in an under tray beneath the car. The under tray weighed in at 200Kg so order to lighten the car for 2015 I removed these and reconfigured the remaining engine bay batteries to maintain power levels. Thus the car was 200Kg lighter - and faster - and unfortunately less stable!
So for the 2016 car I will revert to the under tray battery, remount the differential in the correct orientation, fit a prop shaft and mount the motor and power controller etc into the engine bay.
I calculate these changes will increase overall weight by 50Kgs to about 720Kg all up. This should result in a better balanced car that's easier for me to drive - and when people ask, where is the electric motor? - instead of pointing to the back of the car, I can open the bonnet and say 'in the engine bay'. 
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