Le Mans 24 Hours - why Nissan has gone front-wheel drive

When dreaming up his LMP1 car, Bowlby noted that the current crop of Le Mans prototypes are limited in their rear-end designs.

“To limit the performance of rear-engined, rear- wheel-drive cars, the rule makers have constrained the sizes of the rear wheels, wing and diffuser, and the result is that the aerodynamic efficiency at the back of the car is quite poor,” he explains.

“However, the front has always been considered relatively free, so we thought: why not turn the rules on their head and make a car with lots of downforce at the front? Not only does this give us greater freedom within the rules, but front downforce is generated more efficiently, with less drag. Moreover, with the front end doing most of the work, we could trim out the rear wing and save even more drag, which is invaluable at Le Mans.”

Making a forward aero balance work effectively requires a significant shift in overall mass towards the front of the car. In the GT-R LM Nismo, the engine is in front of the driver, the gearbox is in front of the engine and the mechanical flywheel energy recovery system (ERS) is also near the prow.

“We realised that if we packaged a narrow-vee engine at the front and pushed the chassis back, we can make the back of the chassis into a nice teardrop shape and flow the air around rather than outside the whole car. That gives a drag advantage,” says Bowlby.

Astonishingly, the GT-R LM Nismo has visited a wind tunnel just once, to confirm the data from Bowlby’s computer simulations. Although the prototype looks like no other GT-R, it bears enough of a technical link with the road car to make its name more than a marketing stunt.

“The car is truly a GT-R,” says Bowlby. “It is powered by a twin-turbo V6, although the engine is downsized from 3.8 litres to 3.0, and the use of direct injection is the other main difference. But it has the same maximum rpm, the same even firing and the same vee angle.”

The low-end torque and flat power curve of the engine (“Turbocharged V6 engines are something of a Nismo speciality,” says Bowlby) mean the car needs just five forward gears, reducing wear and tear on transmission components.

Bowlby says the team has seen outputs as high as 1100bhp from the ERS on the dynamometer, which could in theory provide the car with a staggering 1600bhp from its combined power sources. Note ‘in theory’: the lack of development has prompted the team to run a downgraded version of its hybrid system in this year’s race, meaning less than optimum power. 

Still, the lap times from the test day don’t really give an accurate indication of race pace. Nissan didn’t ask Michelin to make a qualifying tyre, because it will use every track session to develop the GT-R LM Nismo.

Cox says a promising result would be “hanging on to the coat tails” of the other hybrid prototypes, although inclement weather could play to the strengths of the Nissan, which is inherently stable and super-fast in a straight line.

On the subject of shaking things up, Nissan’s publicity assault across all forms of media is not without its challenges. Bowlby says: “I was asked whether this open-doors approach distracts us from the engineering activity, but we’re over that. Of course, we face lots of challenges, but if we had done a copy of an Audi from scratch, we also would have faced thousands of small problems.”

Cox emphasises that the project is not a publicity gimmick, and pushing forward the on-track performance will always take precedence. He believes other manufacturers will follow. “Unless we give more access, the sport is in terminal decline,” he says. “When the barriers are up, people are getting less and less interested.”

It’s unlikely a crew from one of the three GT-R LM Nismos will climb onto the podium on Sunday afternoon, but it’s worth remembering that Audi, Porsche and Toyota all experienced growing pains when they embarked on their Le Mans projects. In that respect, at least, Nissan is like its rivals.

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