Build Your Own R35 GTR, Week 5

by akasakaR33
6 years ago
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Summary of this week’s magazine contents:

1) R35 GT-R Story

May 2004. While tests using the SSV400 test car had begun at Sendai Hi-Land Raceway, the “Unit Test Car” based on what Kazutoshi Mizuno envisioned, was being made at fever pitch. Later,stages of development would progressively see a “Platform Lot” and a “Product Lot” test cars, but the UTC is where the base data was collected and problems resolved.

The UTC had the same V35 Skyline Coupe exterior as the SSV400, but was completely different underneath. The UTC was essentially a blending of the GT-R Concept and the Premium Midship Package. The exterior was made of carbon fiber, and the engine, while based on the VQ series 3.5L, was already incorporating VR38DETT concepts such as the liner-less cylinders while also sporting IHI prototype turbines. Collecting data on the car was an onboard 20kg telemetry system by Magneti Marelli, which Mizuno credits with shortening the development of the car.

September. The UTC is finally brought to Sendai Hi-Lands, and development driver Toshio Suzuki joins the team. Up until then, the development process at Nissan was to have the testing staff run the car at the circuit, with the planning staff off to the sides. Mizuno re-did this, bringing all the technicians to the track for development. Further, setting up the UTC were race mechanics from the famous domestic racing team “Nova Engineering.”

Mizuno states “the purpose of the UTC was to develop the development team. In order to create a car capable of 300km which Nissan had never done before, we needed to have racing car level precision parts, and to get everyone thinking on this level, and speaking the same language in order to resolve problems.” However, the initial test results were not promising. The transmission would break leaving the car stranded in the pits, body construction was faulty preventing proper running – and all this with the first Nurburgring test run only a month away, in October. While there were voices saying the run at Nur run should be postponed, Mizuno decided to go anyway.

And the results were not surprising. When Toshio Suzuki took the car out, the body rigidity was poor, not allowing application of throttle in corner until the body settled. And the brakes were inadequate, not lasting even half a lap. The biggest problem was the transmission – not only did the gears refuse to engage, but also disengage, and then faulty software meant that during deceleration the throttle was left wide open. But even then valuable information was obtained.

Back to Japan, where major revisions were made to the UTC. The body was strengthened, the front / rear shapes were changed, the transmission changed to a Borg Warner unit, and the engine capacity increased. So when they revisited Nur again in May 2005 – the UTC was carrying a prototype VR38DETT, larger Brembo calipers, and Bilstein dampers.

But even though the car was better developed, it still could not break the 8 minute barrier. However, compared to the previous year when the UTC could not even attack Nur once, the improved UTC easily lapped Nur 2, 3 times. So upon returning to Japan, the team now focused its efforts on the Platform Lot Test cars, beginning the next stage of development. Compared to the UTC, these PLTCs while looking identical had the R35 powertrain prototypes, with the wheelbase shortened and the trear track widened, and everything other than the trunk made of carbon fiber.

October 2005. The UTCs and PLTCs were taken to Nur for more testing and comparison. With Toshio Suzuki behind the wheel, the PLTCs finally broke the 8 minute barrier. In 2006, several PLTCs were built, to serve as platforms for the various departments and to quicken development time. One car was sent to the Arizona, USA for heat tolerance tests, another to Sendai Hi-Land for snow road testing, etc. All the collected data was amalgamated at the Nissan Techical Center (NTC), allowing improved parts to be sent continuously to all PLTCs.

Finally, the stage was set for the Product Lot test cars and their tests.

2) Mechanism and Factory

Aluminum cylinder heads which support ideal combustion.

While on paper the GT-R has 530ps, what isn’t as apparent is the flat torque curve and the incredible responsiveness of the engine. Obviously in Japan, the only place one can really enjoy the full output would be the straight at Fuji Speedway, and one part of the 300R curve. Mizuno-san, from his experience in Group C racing, realized that the ability to respond quickly from partial throttle to full throttle, with superb acceleration, is the key to being fast, and this is the characteristic he gave the GT-R’s engine.

While choice of the turbochargers is important for this, more important is the actual design of the engine. Various advancements are even incorporated into the cylinder heads. In particular, despite this being a turbo engine, the compression ratio is high at 9.0 – the reason for this being not only to generate sufficient exhaust pressure to avoid turbo lag, but also to take advantage of the 3799cc engine’s response. With a high compression ratio, abnormal combustion and knocking become concerns in a turbo engine. In the worst case, such knocking can cause the tops of pistons to melt, and conrods to bend. Thus turbo engines, up until now, had to have lower compression ratios, delayed combustion, and used fuel to cool the cylinder heads – but this prevented clean burning.

In the VR38DETT, the cylinder heads and blocks were designed for water cooling – in fact this design was revised to allow for the increase to 530ps for 2011 vs the 480ps when the GT-R debuted. In addition the pentroof design was made more compact to also help reduce abnormal combustion and knocking. Further, combustion efficiency was improved with the siamese design aerodynamic port intake port, and the siamese design exhaust port.

As a result, the car has the most efficient combustion to allow for the theoretical clean exhaust ratio (of 1 air to 14.7 gas) at speeds up to 200km/h – maximizing power and environmental efficiencies.

3) Racing Legend

After 1-2 finishes at the 2008 Super GT Series opener at Suzuka and then Okayama Circuit, certain “restrictions” were applied from the third race held at Fuji Speedway.

First, a weight penalty as follows – a win meant a 50kg penalty, 2nd place 30kg, 3rd place 20kg, 4th place 10kg. From 6th place on, cars received a weight benefit – so 6th place meant minus 5kg, 7th place minus 10kg, 8th place minus 15kg, and 9th place and later, minus 20kg.

In addition, due to the overarching superiority of the GT-R machines, an ADDITIONAL 80kg weight penalty was imposed on the GT-Rs. So the number 23 Nismo car, which won the first two races, was burdened with a total of 195kg (First race – pole position, 10kg, plus the win, 50kg, then for the Okayama race, second place on the grid, for 5kg, and the win, 50kg)! However, because the maximum allowed weight of the cars was 1200kg, the 23 car, with this weight penalty, was allowed to minimize the diameter of the restrictor instead in lieu of 95kg.

But the times didn’t really slow down. At Sepang the Kondo #24 GT-R, at Suzuka 1000 the Impul #12 GT-R, and then at Motegi the Hasemi MS GT-R, all won these respective races. Finally at the 8th race at Autopolis, the Nismo #23 car which had meanwhile gradually reduced its weight penalty to 20kg, took the win again.

4) How to Build

This week: The Daylight Running Lamps and Turn Signals

Quote from Mizuno-san: “For 2011, the front bumper now has LED daylight lamps, which increase safety by making the car better visible to other road users. Also, the bumper has two rows of fins which give aerodynamic benefits. ”

These parts are assembled into the front bumper that we made in Volume 1. The last step is to affix the Nissan logo’d license plate, of course – the description is self-explanatory.

5) History of Nissan

This week: Datsun Coupe Type 16

In 1934, one founder of Nissan, Mr. Samekawa, after having learned authentic automobile engineering in the United States, established a mass production factory in Yokohama, which began producing the Datsun Sedan, Phaeton, Roadster, and Truck. The Coupe was introduced in 1937 resulting in 5 variants of the Datsun. Initially in 1937, 207 Coupes were produced, 2.5% of the total 8353 Datsun cars made that year. Initially the exterior design simply changed everything behind the Sedan’s B pillar, but in the later half of 1937, the roof, rear quarters, front fenders, door panels, door sash, side glass, etc.,became Coupe specific, along with special Coupe-only body paint . Despite the high costs of such an arrangement, the Coupe sold for 1900 yen (later 2100), the same price as the Sedan. This resulted in huge popularity, and contributed to the establishment of the Datsun brand.

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Next Week’s Part – Begin assembling the engine