With thanks to the Nissan NISMO PR team
No one has ever attempted to win Le Mans outright with a front-engined, front-wheel drive racing car. To some, the very notion of it seems preposterous when history points to cars with precisely the opposite configuration being the accepted route to glory. Yet if you’re prepared to cast convention aside and look to science, the rule book and the race itself, compelling new answers can be found. Nissan’s is the GT-R LM NISMO.
By adopting a radical front-engined, front-wheel drive layout, the GT-R LM NISMO literally turns the rulebook on its head, finding creative freedom in the same technical regulations that have evolved to restrict the performance of the conventional LM P1 contenders. Combined with a hybrid propulsion system that mates a powerful, super-efficient and compact V6 twin-turbo petrol engine with a mechanical flywheel Energy Recovery System (ERS), the revolutionary GT-R LM NISMO is blessed with exceptional straight-line speed, immense all-weather stability and enviable efficiency.
To understand it’s intricacies and appreciate where it’s advantages lie, who better to explain the thinking behind the GT-R LM NISMO and run through some of it’s technical highlights than it’s creator, Nissan’s LM P1 Technical Director, Ben Bowlby:
“Mad. Brave. Genius.” – The NISSAN GT-R LM NISMO CONCEPT
The GT-R LM NISMO is a pretty wild idea. Where did it come from?
“The car is the star at Le Mans, no question. It’s so important because perhaps more than any other, it’s a real engineering race. As a first year entrant we had to ask ourselves how can we stand a chance of being competitive when the main opposition is fifteen years and several billion dollars ahead in experience and development? The answer – our answer – was to innovate. We don’t have as big a budget as the other guys, but we are rich in ideas. There’s virtually no chance to beat our rivals at their own game, so innovating gives us a better chance at competitiveness.”
What informed your thinking when designing the GT-R LM NISMO?
“To succeed at Le Mans first of all you look at the rule book, and then you look at the race itself. The rules are open to interpretation – as I think we’ve proved! – but the race always throws up surprises. There are so many potential variables beyond your control. Extreme heat, torrential rain, slower traffic, spilled oil and coolant. A big part of the challenge is acknowledging that and designing a car with a wide operating range.”
So what are the GT-R LM NISMO’s key strengths?
“It’s hard to separate individual qualities because the concept and design of the car is a system – every element influences the other. If I had to pick out three things I would say efficiency, stability and straight-line speed. But you have to remember these are the product of the aerodynamics, which in turn were only possible to achieve because of the forward positioning of the transmission and engine and our commitment to run front-wheel drive.”
CHASSIS AND AERODYNAMICS
The GT-R LM NISMO looks very different to its rivals. Why is that?
“For years the leading LM P1 contenders have designed cars that follow the same basic design, so the rules have evolved to find ways of limiting their performance by making it difficult to generate very efficient downforce at the rear of the car. It’s also difficult to make maximum downforce, because the dimensions and shape of the rear wing are also restricted. 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 oodles 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.”
Clever stuff. Tell us more.
“Achieving a forward aero balance is quite a trick in itself, but to make it work you need an equally radical shift in mass and tyre distribution. It was at this point we took our ideas a stage further and thought, “What if we put the engine ahead of the driver?
“It was natural that we chose a powerful, compact twin-turbo V6 like that in the GT-R road car, especially because it meant we also had room to package the ERS system in the front. By mounting the gearbox ahead of the engine and the crash structure ahead of that, we have a chassis that complies with the regulations, has all its major mass over the driven wheels, gives us all-important forward aerodynamic balance we’d been chasing, and lends itself to a very efficient, low-drag teardrop shape.”
Why is low drag so important at Le Mans?
“So much of the Le Mans circuit is comprised of long, high-speed straights. Low drag gives us a high top speed to eat-up those straights! Having a straight-line speed advantage is also the simplest, safest way to pass other cars. We’ve tried to make a car that gives our drivers that comfort factor of knowing they’ll be able to pass at high speed rather than having to mug slower traffic in the braking areas and corners. It’s a less stressful, less fatiguing, smarter way to race.
Low drag also aids fuel efficiency. The amount of fuel consumed in a lap is now mandated, so you may not exceed those limits prescribed by the rules and regulations. Low drag means you’re not sat on the straights for a long time with wide throttle openings, so not only does a slippery shape mean you’re going faster, but it also means you’re using less fuel and thus increasing your efficiency.”
Describe the GT-R LM NISMO’s propulsion system
“In simple terms we have gone with a petrol-electric propulsion system comprised of a compact, twin-turbocharged 3.0-litre V6 internal combustion engine (ICE) petrol engine, and a mechanical flywheel kinetic Energy Recovery System (ERS) that runs in the 2MJ class. Turbocharged V6 engines are something of a NISMO speciality, so our philosophy for the ICE was to build a super-efficient version, which has excellent drivability at relatively low rpm. It’s very, very torquey with a very flat power curve, which means we need only run with a 5-speed gearbox. This means we’re changing gear less and putting less wear-and-tear on the transmission components. The engine also has spectacular thermal efficiency, so we extract the most power we can from every last drop of petrol we use.”
What about the Energy Recovery System?
“We are running a flywheel-based energy recovery system, as Audi does, but where they use an electrical linkage we have gone with a mechanical system. It’s different and it’s smart and it has huge power potential. In tests on the dyno we’ve comfortably produced 1100bhp from our 8MJ KERS system alone. Combined with the internal combustion engine means have the potential for a little over 1600bhp at our disposal.
“Unfortunately due to the project’s extremely challenging timeframe – less than a year to form the team and design, engineer and develop the car from scratch – we’ve had to be pragmatic and scale things back with the hybrid system for this year’s Le Mans. That’s the flipside of innovation: it hurts when all the pieces don’t quite come together in time. However, we are going to learn a huge amount about getting the maximum from the V6 petrol engine in this year’s race, an you can be sure we’ll be back at Le Mans with full force in 2016.”