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Monday, 2 February 2015

Nissan GT-R LM NISMO Finally Lands From Another Planet


Forget Formula 1. All the cars look 95% the same. Forget American Handegg or a bowl with a cape or whatever the crap Channel 4 is bothering with on the USA's behalf. That's just armoured rugby with forward passes and more breaks than a cricket match. Forget whatever you were just doing. It's not NEARLY as interesting as Nissan's newly-revealed LMP1 racing car, set to tackle the World Endurance Championship and by extension the Le Mans 24 Hours this year.


This car has been the source of rampant speculation for months now, with signs pointing towards it being something radical, perhaps an evolution of the DeltaWing and subsequent Nissan ZEOD RC to suit top-flight LMP1 regulations, or something using a GT-R road car engine, or maybe even something with an engine in the front. Will it run Le Mans without a rear wing? Is it true that total power output will be 2000+ horsepower? Will it be front-wheel-drive? Will the wheels be different sizes?

So, let's get some headline stats and specs laid down:

> This is only the second-ever modern front-engined LMP car, following a mildly successful Panoz.

> Said front-mounted engine is a new "very modern but conventional" direct-injection 3.0 Twin-Turbo V6, connected to a 5-speed sequential gearbox. It powers the front wheels only. The exhaust pipes exit upwards, just in front of the windscreen!

> There is, of course, a significant hybrid system in the form of a mechanical flywheel ERS. It harvests energy from the front axle, possibly both, and the energy it generates then powers all four wheels, biased towards the front.

> The rear wheels are four inches narrower than the front ones, at 9", partly as an advantage of front-wheel-drive (less tyre = lower drag) and also to widen the air channels at the back of the car. The diameter of all the wheels is just 16" - the same as my parents' Ford Galaxy people carrier.

> The engine's power output is a seemingly unspectacular 550 horsepower. However, when the dual-axle ERS boost is running at full power, it adds 8MJ of energy into the mix, which translates to an added 700bhp or more, making a total maximum power output of around 1250 horsepower! Weight will be no lower than 880kg, giving a power/weight ratio that rivals a Moto GP bike.

> Some of the technology in this car (including perhaps the engine?) will appear in the R36-generation Nissan GT-R road car - set to appear in 2018 - in some form or another.

Basically, this scarlet Batmobile is batshit insane on every level. If your brain hasn't melted yet, keep reading.

Here's a simplified image of how all that back-to-front madness is packaged.

Unlike all the other LMP1 cars we've seen recently, there are no huge openings in the body to let the air flow - for example - through the front end and out down the side of the car. It all appears to be enclosed, save for the openings above the wheels which have to be there by regulation to stop it flipping. Here, it goes in the front, does magic things and then all goes out through the back, through internal channels that start just behind the front splitter and at least partially fill the huge empty spaces either side of the cockpit before firing out of the back, mostly above the large diffuser. This is called "through-flow" aerodynamics, and would explain why rear tyre width made way for larger air channels. Getting the air to calmly flow all the way through the car rather than rushing around it creates much lower overall drag, a way to save fuel and increase top speed. In a 24-hour race, you want to do both of those things.

A front-drive layout plays a big part in making this concept work. By putting all the big bits up front (even the KERS components are in the front half, stretching under the driver's legs as he/she sits in an F1-style raised-legs position), the sides of the car are free to fill with air channels, whereas a mid-engined car uses the sides to store radiators/convectors to cool an engine that naturally doesn't get as much air as an engine at the front does. As a result, only the Nissan will have proper flow-through aero, which could well be an advantage. In fact, so much faith has been put in the aero that some powertrain parts, such as the twin turbochargers, are mounted high up to make room for the air channels between the front wheels. Even the driveshaft for the KERS runs through the vee of the V6 engine, rather than underneath it all. The trade-off is a slightly higher centre of gravity, but as the entire powertrain is within the wheelbase, that's not the biggest deal.

This layout is of course also the reason why the cockpit is so much further back than any other LMP car racing this year.



But what of that powertrain? The 3.0 V6TT is supported by a mechanical flywheel ERS, often called "Flybrid" ERS. The Energy System harvests significant heat energy from the brakes and stores it in a spinning flywheel, much like the Audi R18. When the car accelerates out of a corner, energy is deployed from the flywheel mounted in front of the cockpit to power the front wheels alongside the always-running engine, however, if the total power is too much for the front wheels to handle, power can also be sent rearwards at the same time, through a driveshaft to a high-mounted rear differential. Nissan targeted total power of over 2000bhp, but to ensure the car is more likely to go 24 hours without blowing up, it's been pared back to roughly 1500bhp overall, according to Racer (who saw the car and met the team in December), although Jalopnik and other news outlets are saying 1250bhp, perhaps as a minimum figure. With only five gears instead of the normal six, one could assume that there's also monstrous torque on offer throughout the meat of the rev range. As the extra 700+ horsepower from the ERS comes in one short blast at a time, the narrower rear tyres can handle its share just fine.

The rear diff, and the two half shafts it spins to drive the rear wheels, are mounted high up to make room for the huge air channels. This is no mean feat of engineering. Convention dictates that the differential and half shafts must be in line with the centre of the wheels they're driving, because, well, that's how axles work. However, that would've meant running a rod through both air tunnels, reducing aero efficiency, so to have his cake and eat it, chief designer Ben Bowlby decided to have a tall diff housing that connects to high-mounted half shafts... which then connect to their own small gearbox each! Said gearbox then has another small driveshaft protruding from the bottom, in line with the rear wheel so it can turn it. It all sounds extremely complicated, because it is.


Clearly aerodynamics are a big deal here. Some still believe that when it comes to the main event at Le Mans, Nissan will run the car without a rear wing. Why? Being front-engined, the weight distribution is different to that of the now-traditional mid-engined cars, being more front-biased. Good aero balance follows the weight balance, so with more weight in the front half, there is less need for downforce at the rear. With all this through-flow wizardry, perhaps it could get away without a rear wing, significantly cutting drag? We shall have to wait and see. Higher-downforce circuits will see it run in the configuration pictured, that much is for sure.

The people driving this crazy car are not yet all known. After the Superbowl commercial aired last night, Nissan announced that Marc Gené would be one of them. The Frenchman won Le Mans in 2009 with Peugeot, and has been racing in the World Endurance Championship (WEC) with Audi after Peugeot pulled out at the end of 2011, having also been moonlighting at Scuderia Ferrari as test driver since 2004. As for the other five - plus three more for a third car at Le Mans - place your bets. I think Michael Krumm has to be one of the senior drivers getting a race seat, while 2011 GT Academy Jann Mardenborough has already driven the car at COTA to shoot the Superbowl ad, so he must be in with a shout too. Nissan have said it will be a mix of GT Academy winners, Americans, Japanese drivers and successful drivers like Gené, to show that it's a serious global team.

Nissan's key advantage in designing this car is the fact that they're starting from scratch. Audi have a tried and tested formula, which, as it's still winning races, will only be evolved, not changed completely. Porsche borrowed heavily from their VW Group stablemates - although they gain kudos for designing a new V4 Turbo engine - while Toyota started with a modified third-party chassis and the 3.4 V8 engine from a SUPER GT car. Only Nissan, with motorsports arm NISMO heavily involved of course, could start their 2015 car with a blank sheet of paper and some ideas, and from the start they wanted to use this opportunity to stick two fingers up at the established players in a big way. Of course, there is inherent risk in being radical; will all this crazy flybrid gubbins and extra gearboxes work properly? Will it end up being overweight? Will the through-flow aero prove to have any noteworthy advantage over the competition? Is front-wheel-drive even slightly a good idea for an LMP car? The only way for any of this to be likely to pay off was to go all-out and put total faith in it all being a missed trick up until now. Either they've just given themselves a mountain to climb and will start the WEC season with their car breaking down and qualifying last in class, or they've hit on something nobody else was brave enough to try, and will be right up near the front come June. There is no middle ground with something this different.

The only certainty here is that nothing is certain. We'll just have to watch it race and find out!

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As is typical for posts of new racing cars, here's a dump of the photos I couldn't fit around the text. Download the whole set of press images in super high res here!





The following images are from RACER.com, where I got most of the technical info. Photos by Marshall Pruett:








Images from Nissan unless otherwise stated. This has been written for SmallBlogV8. Do not repost the text without permission. Follow me on Twitter @SmallBlogV8!

NISSAN GT-R LM NISMO Technical Specification

Configuration
Front-engine. Front-wheel-drive

Engine
Nissan "VRX 30A" NISMO: 3.0 litre, 60 degree V6, direct injection gasoline twin-turbo

Transmission
5-speed + reverse sequential gearbox with pneumatic paddle shift system. Epicyclic final drive reduction with hydraulic limited slip differential
Tilton 4-plate carbon clutch assembly

Chassis
FIA Homologated weight: 880 kg. Right-hand driving position
68 litre capacity FT3 fuel tank featuring electric lift and feed pumps. ERS housed ahead and beneath driver’s feet in self-contained module.

Bodywork
Carbon-composite body panels. Polycarbonate windscreen with hard coating
CFD and full scale wind tunnel developed ultra high efficiency bodywork geometry, adjustable rear wing.

Suspension
Penske dampers with four-way adjustment front and rear, hydraulic rear anti-roll bar system.

Brakes
6-piston front and 4-piston rear calipers. NISMO Brake-by-Wire active brake ERS blending. Driver adjustable brake bias.

Wheels
BBS centre-lock, magnesium forged 16”x13” front and 16”x9” rear

Tyres
Michelin 31/71-16 front, 20/71-16 rear radials

Electrical
Cosworth engine control unit featuring: Engine control, gearbox control;
Driver adjustable traction control, Anti-lag system control, Brake-by-wire, lift-and-coast fuel conservation, Drive-by-wire throttle control and ERS deployment strategy control

Interior
NISMO 5-point harness
Lifeline lightweight extinguisher system

Data / display system
Cosworth Electronics with NISMO steering wheel mounted LCD

Dimensions
Length: 4.645m
Width: 1.9m
Height: 1.03m
Minimum weight: 880kg
Full tank capacity: 68L

1 comment:

  1. Wow, amazing car, pretty and faster, excellent post, thanks for sharing..!! Cars auction

    ReplyDelete