The upcoming Nissan GT-R is already a streetbound race car, but rather than just toss the tasty-enough VK V8 in the engine bay and call it a day, Nissan's going all out with an engine befitting an actual racer. The VK45 was rumored to be the engine for the GT-R, but Nissan felt its overall style was more Grand Touring than was appropriate, so they reached back into history and pulled out a little number from the R390 LeMans racer.
Follow the jump for the story. Thanks to Chuck for the tip!
[Source: 7Tune]
The R390 sported a 3.5 liter V8 known as the VRH35L, which was essentially recreated as a V6 production engine in the form of the upcoming GT-R's VR38VETT. Even though it loses two cylinders, it gains 300cc of displacement, for a total of 3.8 liters. Oh yeah, there's a couple of turbochargers thrown in for good measure, too. Despite the amount of air it can pump, the VR38 is a compact mill with lots of trick touches. Among the most interesting features, and probably the ones that tuners will hate the most, are the integrated turbine housings in the exhaust manifolds. Having the impellers right in the manifold keeps weight down and improves response, while also making the overall package more compact and thus easier to nestle down into the frame. Each cylinder bank has its own independent intake manifold, which is the main thing you see when lifting the hood. The cylinders fed by that plumbing are occupied by lightened pistons, which are in turn flung around by svelte connecting rods and crankshaft, too. Cosworth had a hand in engineering the engine, which has an alloy block with linerless bores, plenty of magnesium alloy pieces, an oiling system capable of coping with high g's, and an eagerness to rev in a way 3800ccs usually aren't.
The GT-R will be impressive when it debuts in just a couple of months, and from the numbers, it looks like it'll give a Porsche 911 Turbo quite a run for its (big pile of) money. The horsepower figure for both cars is 480ps, and while the GT-R gives up some torque to the Porsche, the GT-R rips off equally quick dashes to 100 km/h (3.9 seconds) and has been designed with vehicular balance as an overarching theme. While the chassis of the GT-R can handle more power, Nissan's considerable Group C racing experience showed that cars with better balance are faster than horsepower champs. With a front engine/AWD layout, it'll be less a widowmaker than the 911, which can get wiggly at times. How's this sound – performance equal to (and potentially better) than the 911 Turbo for half the price (7.9 million Yen versus 18.2 million Yen)? Yeah, we thought so. Besides, the GT-R isn't stuck in some kind of iconoclastic styling purgatory the way the 911 is
Under the hood of the Nissan GT-R: Engine details revealed - Autoblog
Even though the 2008 GT-R’s release is still just under two months away, Holiday Auto has been hard at work putting together a 10 page article exploring the new GT-R’s engine, chassis, driveline and interior features, some of which is old news by now but included nonetheless. We’re told that Nissan was in fact looking at a V8 engine to use in the GT-R in its early stages of development but found that the VK45 from the Nissan President wasn’t an engine worthy of the ‘R’ in the GT-R’s badge. Although it could satisfy the power, torque and driveability deemed necessary for the GT-R, the way in which it delivered those attributes was more befitting of a large saloon than a GT car. There was also a status problem, the VK45 being associated with Nissan’s luxury sedan would cause problems with potential GT-R buyers who were looking for more exclusivity… well exclusivity is what they got.
The VR38VETT
Holiday Auto broke the news about the existence of a VR based GT-R engine last month, and since then has gone one further and given us a actual alphanumeric designation: VR38VETT. The VR38 is actually a recreation of the famed VRH35L V8 powering the R390 Le Mans car albeit in V6 form. A lot of knowledge gained from Group C and endurance racing has allowed Nissan to take the performance aspect of the GT-R that little bit further (over say, a VQ based engine) by taking the basic design of the VR38 and using it for the new GT-R’s V6 engine block and cylinder heads. A surprising feature of the twin turbo system is the ‘Integrated Exhaust Manifold Turbine’ where the exhaust manifold and turbo exhaust housing are formed as one piece. We’re told this is for weight saving, packaging and high response and was chosen over the more costly ‘motor assisted twin turbo system’ that was predicted way back in mid-2004. What all this has resulted in is an engine design that could be viewed as two 1.9L straight 3-cylinder DOHC turbo engines joined by a common crankshaft, with separate intake manifolds and throttle bodies for each bank. The intake manifold is actually the centerpiece of the engine bay, its intake runners being used as a design feature of the VR38VETT as shown in the CG mock up image shown below.
Cosworth’s involvement in the GT-R’s engine development has been mentioned before on many occasions but until now there hasn’t been much information on what they’ve actually done. Holiday Auto tells us the GT-R’s aluminum engine block is a ‘monoblock’ design, meaning it doesn’t use sleeves inside each cylinder bore so that the pistons make direct contact with the block. Cosworth has also reduced the weight of the crankshaft, conrods and pistons to achieve maximum response and a free revving nature that belies its larger 3.8L capacity. It comes as a surprise too that the whole engine looks a lot shorter than what you would expect a 3.8L engine to be, its compact design and light weight being a major contributing factor in the cars overall balance. Many other parts such as the cam covers, timing chain cover, oil pan and a multitude of bolts, screws and washers are all made of magnesium. The GT-R will also use a semi-wet sump system which can handle higher g-forces over a traditional wet sump which start to suffer from ‘oil sloshing’ at around 1.8g. As pointed out in our previous article, the power delivery of the VR38VETT is extremely linear and does not drop off after hitting maximum power at 6,800rpm which was a big factor in proceeding with the development of an all new engine. From as little as 1,500rpm a powerful surge can be felt with - what seems like - all 480ps available with very little throttle application. It has been said that there are very few people with enough skill to drive the new GT-R at its limit, this limit being so high that a driver of average skill level would never be able to test the boundaries of the GT-R’s performance… this could possibly be an exaggeration on Holiday Auto’s part, but the point has been made clear: the new GT-R is every bit a Supercar.
Group C Influence
Kazutoshi Mizuno, who headed Nissan’s Group C and Le Mans racing programs, has brought a lot of Group C racing knowhow to the new GT-R in the form of an overall design theory rather than just a particular specification level or layout on paper. Where the BNR32 GT-R was specifically designed to conquer the Group A Championship in Japan (and subsequently Australia) and then sold on to the public, the new GT-R takes the opposite approach being a car designed for the public using knowledge gained from Nissan’s racing exploits. The Group C cars of the early 1990s were all about outright speed and this has been applied to the new GT-R right from the word ‘go’, every part of the car has been designed to gain maximum speed without upsetting the cars outstanding balance. As an example, during the Group C racing era it was found that cars with around 750hp were more drivable and could actually lap quicker than cars with 1,000hp and thus detuned, so this led the GT-R design team to limit its output to under 500hp despite the fact that the chassis could handle well in excess of that figure.
Multi Function Display and Price
The new GT-R’s Multi Function Display will offer more information than previously available in the BNR34 GT-R. Four main presets categorize the information:
Preset 1: boost pressure (1.5kg/cm limit), oil pressure and temperature
Preset 2: selected gear, gearbox oil pressure/temp
Preset 3: cornering g’s, accelerator opening
Preset 4: acceleration g’s, braking g’s, front and rear torque split
Nissan Japan’s dealer network has been given pricing for the officially named ‘Nissan GT-R’ at 7,900,000 yen with certain options like a Bose Premium audio system incorporating - and this might come as a shock to current GT-R owners - a subwoofer mounted over the transmission tunnel between the rear seat footwells thus rendering the GT-R a strictly 2+2 seating arrangement. About a year after the GT-R has been released in Japan there will also be a model to go head to head with the Porsche 911 GT2, possibly to enter the market badged as a ‘Nismo Version’ and based on a V-Spec model.
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