What is a twin tank conversion?
A second tank, normally around 4 or 5 gallons (20 litres) capacity, is installed in the boot and joined into the flow and return fuel pipes by way of electrically operated solenoid valves controlled by a switch on the dashboard. A coolant fed heat exchanger is installed in the fuel pipe just before the fuel filter. 100% WVO or SVO is put in the main tank and fossil diesel is put in the second tank. On starting the engine, the driver selects the diesel tank and starts the engine on diesel as normal. As the engine warms up, the heat exchanger heats the fuel before it enters the fuel pump. Once the engine is up to full temperature, the driver switches to the main tank and runs on vegetable oil which is heated to (ideally) coolant temperature of around 60C. At this temperature vegetable oil is almost as thin and runny as fossil diesel and burns perfectly with little difference in performance and minimal damage to the engine components. About 5 or 10 minutes before stopping, the driver sele
