DIY GTR Build, Vol 4.
Summary of this week’s magazine contents:
1) R35 GT-R Story
The first development mule, the SSV400, begins testing at Sendai Hilands Raceway on May 17 2004.
In early 2004, Mizuno-san realized he needed to do the following for the supercar he was seeking – lap Nurburgring under 8 minutes, have a top speed of over 300km/h, and a power to weight ratio of under 4.0kg/ps. These were numbers that clearly could not be accomplished in the production car based Skyline GT-R. At the same time, the reality was Nissan had never made such a car, either. Hence a new development team was needed.
The SSV400 development car was brought to Sendai Hilands in mid May 2004. While the SSV400 had been developed by the previous CVE (Chief Vehicle Engineer) and so Mizuno-san had never touched it, it could still be used as a testbed for engine development. At the same time, it could be used to nurture and train the team members.
The SSV400 was a 4WD version of the Skyline V35 Coupe, which used the FM package that Mizuno had developed. Because the same chassis was used on the V35 sedan which DID offer 4WD, this is the same vector by which the previous Skyline GT-Rs were developed. Appearance-wise, the rear fenders were enlarged, and the car was wearing fatter tires than the standard. The rear spoiler was similar to the R34 GT-R’s. The front brake calipers were the same as the V35 Skyline, with the calipers at an angle and not parallel to the ground. So it can be seen that lots of the underpinnings were from the V35 cars. The engine though was 3.5-3.6 liters with large capacity twin turbos – this later changed to smaller turbos in the 3.8 liter version so as to focus on responsiveness. (Note: this SSV400 was NOT the same one that Toshio Suzuki had tested – that would be the next one)
Sendai Hi-lands is a technical track that is 4063 meters long, lots of ups and downs, and a surface with very low mu compared to other circuits. It could be said this is the track in Japan most similar to Nurburgring – and for this reason was chosen as the domestic test track. The Nissan drivers chosen to drive the SSV400 at this first testing were their best, “AS Class” drivers – Matsumoto, Kamiyama, and Suezaki. But even for them, the new GT–R’s goals were unchartered territory. They knew as well that the benchmark was to be the 911 Turbo, and that this would be most difficult benchmark. Hence as Mizuno had stated previously, this was not just about developing a car, it was also about developing the people on the team.
The real testing would begin in August 2004, when the unit test car that Mizuno had designed was built.
2) Mechanism and Factory
The new IHI twin turbos give the VR38DETT incredible response and acceleration power. Japan in the 80s and 90s relied heavily on turbo engines, but these all but disappeared in the 2000s. Environmental concerns came to the forefront in the late 90s, especially the need to reduce CO2 emissions. In Japan in particular, the Year 2000 Exhaust Regulations were especially strict, meaning that most turbo cars including the Skyline GT-R with its RB26DETT had ceased production by 2002. After this, most domestic cars saw a move to larger non-turbo engines.
The were two basic reasons for the disappearance of turbos. First is because, immediately after start-up clean exhaust cannot be generated. As the exhaust energy gets absorbed by the turbos, the temperature of the catalytic converter does not rise, hence not allowing the converter to “clean” the gases, and therefore not able to meet exhaust regulations. The second reason is that, in order to prevent the exhaust manifold and turbos from getting too hot, up until now it was necessary to purposely inject excess fuel and delay spark discharge and have “fuel cooling” – which of course means an excess of toxic exhaust.
The R35 solves the first problem by way of a 2-state air system, which results in raising the temperature of the catalyzer right after start up, for cleaner exhaust gases. And, the structure of the turbos are different, in that the exhaust manifolds are incorporated. With no large flange in the way, exhaust temperatures remain higher (ie no heat sink), and more energy is available to move the turbines. Also having no flange means the catalyzer is closer to the combustion chamber, so the catalyzers can operate even more quickly. For the second problem, use of a special heat resistant alloy in the turbo and exhaust parts means no fuel cooling is needed. This results in a fuel-air ratio similar to a non-turbo engine, and further with more accurate spark discharge, cleaner burning and also better gas mileage.
3) Racing Legend
The Nissan GT-R race car made its race debut on March 2008, at the Suzuka GT 300km race, the season opener of the Autobacs Super GT race series, with 1-2 finish – worthy of the GT-R name.
Race week began on the Friday before the event, but with rain, none of the Nissan cars nor their rivals could produce good times. The best time for the number 22 Nismo car was 2’03″978 by Michael Krumm. The next day, Saturday the weather had vastly improved, and the number 23 Nismo car driven by Benoit Treluyer set the best time at 1’51″542 – the number 12 Calsonic car driven by Tsugio Matsuda with a 1’52″378, and the other Nismo car number 22 beat this. Hence the top three cars were GT-Rs. The afternoon session was similar, with the end result the GT-Rs being the top three fastest cars, and the fourth fastest the number 36 Lexus SC430.
Race day on Sunday, and the starting grid showed the first two cars to be the number 22 and number 23 Nismo cars. While the 22 car lead until midway, the 23 car finished first, for a Nissan 1-2 finish.
4) How to Build
This week: The Right Rear Suspension
Quote from Mizuno-san: “The GT-R’s suspension has alignment precision which has never been seen on a production car before. Further, use of the monotube type Bilstein Damptronic (electronically adjustable shock absorber) allows the best driving dynamics”
The parts are assembled just like a real suspension – the description is self-explanatory.
At the end of the day however, putting together the tire/wheel, brakes and this suspension unit, you end up with this:
5) History of Nissan
This week: Not featured
Next Week’s Part – LED Daylight Running and Turn Signal lamps.