A few years ago Nissan produced a very lightweight motor for their Nissan ZEOD RC (Zero Emission On Demand Racing Car). The basic statistics were 88lbs (40kg) with a three cylinder 1500cc capacity fitted with a turbocharger. It produced 400hp – which at the time was a better power-to-weight ratio than a comparable Formula One engine.
The plan was to run the ZEOD RC as an electric car for some laps of the Le Mans 24 Hour race, with the DIG-T R 1.5 providing power for the rest of the laps. Nissan had worked out that the car could do one full lap per hour under electric propulsion with the rest of the laps powered using this lightweight motor.
Size matters when you are racing as that means weight and Nissan’s engine was 50cm tall, 40cm long and 20cm wide. It could rev to only 7,500 rpm which is very low for a racing motor – although the Chevrolet V8 is similar, in part due to it’s overhead valve configuration. In comparison, the first Ford Cosworth DFV in the late 1960s also produced 400hp with double the capacity and with far more cylinders! The DFV could spin to 9,000 rpm as well.
One way to achieve the power from such a small motor is to reduce the friction as much as possible and Nissan partnered with the French oil company, Total, to develop higher grade oils and to eke out the maximum burn/power from each shot of fuel per cycle.
Nissan mounted the engine with two electric motors such that they shared the same gearbox with the electric motors powered by lithium-ion batteries. The DIG-T R motor was effectively doing two jobs – charging the batteries and driving through the gearbox. The ZEOD RC was controversial from the start – it was designed by Bill Bowlby who had created the Nissan sponsored DeltaWing several years earlier and built by Panoz in the US. The two cars were pretty similar in design and layout and as a result Nissan were sued by DeltaWing with the combatants settling out of court in 2016.]
The ZEOD RC entered the 2014 Le Mans 24 Hour race in Garage 56 – for experimental cars – and the garage that DeltaWing had used a few years earlier. The car qualified 27th of 55 entries, so mid-pack which was a great effort. The race was a short affair, lasting a mere 5 laps before the gearbox broke and to put that into perspective, the winning Audi covered 379 laps. The team did consider the race successful – they managed to get one full lap on pure electric power and the car topped 300 km/h at one point. So they claimed a couple of records: the first electric powered racing lap and one by a 3 cylinder car.
The DIG-T R engine was described by many reporters as “revolutionary”, yet it wasn’t really. The Renault RS01 F1 car of the late 1970s was fitted with a 1.5 litre turbo V6 that produced over 500hp. When you consider that all the components of the Nissan motor had been used many times before, I would say it was an “evolution” not a “revolution”.