Marcel Fassler and Benoit Treluyer say that the Audi e-tron is faster and more flexible than the Ultra, but that the race performance will be heavily influenced by the fuel consumption of the hybrid.
The 2011 Le Mans 24 Hours winners told AUTOSPORT that the Ultra has an advantage due to its optimised weight distribution but that the extra power and traction of the e-tron should make it ultimately faster as long as the drivers can make the e-tron's 58 litre fuel capacity last for the same number of laps as the Ultra's 60 litres.
"They are very close and hopefully we can do the same number of laps with a bit better performance as we have the extra power on the exit of a few corners," said Treluyer.
"The weight distribution from the rear axle to the front is close but the centre of gravity is higher than the ultra but you can't feel it, on the paper it must be better on the ultra but you can't feel it and we set up the suspension and dampers to dial it out," he added.
"If it rains you feel more advantage though and you have to be careful that it doesn't come on too strong and the car is now nice to drive and it has good balance."
Treluyer added that he thinks the e-tron will be able to cover the same distance as the Ultra but that they may need to use the hybrid system to save fuel.
"I think we will do the same number hopefully because the two litres less make it harder. It is difficult to be the same but we can manage it. We can use the hybrid system not in terms of performance but in terms of saving fuel. It will save a bit but it is not a big amount," said Treluyer.
Fassler agreed that fuel will be important for the strategy of the e-tron and that if it rains the e-tron will have an advantage.
"We only have 58 litres so it depends if we can do the same number of laps. It is quite close and if we can do it then we have no disadvantage but if they can do one lap more it will be not so easy for us," said Fassler.
"We saw in Spa that we have a small advantage in traction at 120kph and we can heat up our tyres a bit better than the rain too in the e-tron."