I did check in several trips around england and the Renault master 2.5 turbo diesel reg. 1996 with no ecu and so forth electronics with a 16 10x10cm plates dry cell and draggin 15/20 amps with kon (1/1.5 teaspoon of caustic soda x 2lt solution) is doing 12 km/litre of diesel while b4 was on the 8.4 km/litre on the mtorway.
On the city is 7.5 with hho cell and 6.8 without. . . a part from the boost on the torque you can feel it while using the trottle . . . 🙂 so