Build Your Own R35, Week 13

by Rhodri Jenkins
5 years ago
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1. R35 GT-R Story

2008 Model, based on the North American Version, released!

In May 2008, at a press event held in Portugal called “Nissan 360,” Mizuno-san told the world press that the R35 GT-R would continue to improve on a yearly basis.

He claimed that, even though the chassis numbers would not change, the change to the car could be felt on driving. As proof, he offered revised numbers for Nurburgring – whereas the first year car had posted a best time of 7 minutes, 38 sec 54, the newer car had posted a best time of 7 minutes, 29 seconds 03.

So exactly what changes were made to this 2008 model?

Mizuno-san claims “mainly ride improvement modifications.” In actuality, the 2008 model is the same spec as the North American model that was released in July 2008. One spec for the world. It just turned out that the modifications made for the NA model, made the car faster – and these changes were fed back to the JDM 2008 models as well.

Specifically:

1) Spring rates changed by 0.1kg/mm front and rear. Changed the compression of the shock absorbers as well.

2) Changed the hardness of the transmission and engine mounts, in order to create an enjoyable engine sound.

3) Eliminated brake pad squealing – however the material was not changed.

Thus, Mizuno claimed these were changes in the build process, not in the design specs. For example – springs on a car are normally built to JIS or ISO tolerances, of plus or minus 10%. But for the GT-R, the tolerances are even higher. So the result of this was to make the levels of precision during assembly even higher, thus the NA spec model improvements were done within these tolerances. Anything outside of these tolerances and the would have had to have been an application to the relevant ministry as a specification change.

So where did the 10 second improvement really come from? Turns out that the initial record setting time was done when the track had two wet spots. Elimination of those two spots resulted in 4-5 seconds faster. The ride improvements resulted in the other 4-5 seconds.

Of course, the result of this 7’29” time was to fire up the competition – the chief engineer of the Porsche 911 doubted the veracity of this claim. Then, on 27 June 2008, the Chevy Corvette ZR1 claimed a lap time of 7’26”04, followed on 18 August by the Dodge Viper SRT-10 claiming a time of 7’22”01.

Photos, pg 7.

Upper left – the first left handdrive GT-R.

Caption – while the R33 and R34 were sold in limited numbers outside Japan in the UK, the R35 was the first to have left hand drive. So highly anticipated by fans worldwide. Also, while different driving environments usually means different spec cars of the same model, the GT-R is the same spec worldwide, except to allow for differences in gasoline octane readings.

Middle left – NA spec, all 4 brake lights light up. JDM had to wait until 2011 for this.

Middle center – information is English, and the speedometer reads to 220mph.

Middle right – the front transaxle and prop shaft are on the right side of the R35. So actually, for ideal balance, left hand drive is more accurate.

2. Mechanism & Factory

The takumi who built it, guarantees it!

Before leaving the clean room altogether, after assembly, each engine is tested by attaching a motor to spin the internals. Here, camshafts, compression, valve timing, etc. are checked for friction loss. Any “fails” and the engine does not leave the clean room, it is torn apart and reassembled.

But there are times where even though an engine passes these tests, a Takumi, when turning by hand, has detected feeling something was amiss. Subsequent disassembly and inspection have shown the presence of contaminants the machine test failed to spot.

Only when an engine has passed these tests are the turbos and intake manifold attached, and the engine allowed to leave

The engine is then taken to the engine test bench room – where it is finally fired up, and “broken in” while the engine’s performance is measured. During the test – the man who knows the engine the best – the takumi who built it – stands by watching – and thus guaranteeing its performance!

In this way – no GT-R engine ever generates numbers LESS than what has been published.

3. Racing Legend

The Tokachi 24 Hour Race – production spec car.

While the Super GT spec cars were running in and winning races beginning in the 2008 season, a different kind of project was happening – preparations for the only 24 hour endurance race in Japan, on July 20-21 at Tokachi raceway in Hokkaido.

The project was based on using a production GT-R, but would allow for the development of Nismo option parts and competition oil, as well as to demonstrate the durability of the GT-R. Hence, very few modifications from the production car were allowed. In the beginning, even the fuel tank was standard, although later for safety reasons it was switched to 95liter safety cell. Also, air jacks, needed for an endurance race, were added.

The rollcage was not welded in, but rather bolted in, and while spot welding the chassis is the norm, in this car, there was no spot welding – to demonstrate the high rigidity of the production car.

However there were efforts to lighten the car – the bonnet and trunk lid were made of dry carbon fiber, side windows replaced with acrylic panes. The a/c condenser was removed, and netting added to protect against flying debris. The radiator, intercoolers and oil coolers were OEM, as was the engine.

4. How to Build

Upper Rear Suspension Member

Mizuno quote – The GT-R rear suspension member is actually two pipe frame sections, top and bottom. While complex it is constructed very precisely, and provides a good ride but with extremely high rigidity for stable handling.

Note: with this, the rear suspension member assembly is complete. Going forward, other components will be attached to this piece.

Note: No History of Nissan this week.

Next week: Front Diffuser Panel