Car Feature>> Garage Ito Prostock GT-R

You are looking at one of the most far out GT-R time attack projects ever created. It cost a massive $350,000 to build and has yet to see the light of day on a race track. It all started back in 2006 when Hiroya-san, a very good customer of Garage Ito in Osaka, decided to see if he could challenge the lap time record at Tsukuba set by the HKS CT230R. Hiroya-san is a very successful business man, and with his company pretty much taking care of itself he decided to dedicate some more time to his passion, cars. On top of having Ito-san build him the craziest BNR34 the tuning industry has ever seen, he also decided to set-up his own tuning company in the outskirts of Tokyo.  This is how ProStock Racing was born, now an established tuner catering to GT-Rs and Zs of all generations. But the question remains, what on earth ever happened to his mighty red R34?

Before we get into that let's take a closer look as this GT-R, with some in-depth pictures that show the amount of work that went into this build. Ito-san of Garage Ito was given simple instructions, whatever needs to be done to make this car the fastest, do it. Hiroya-san has bucket loads of determination, the kind of drive you often see in successful men. He has nothing to prove with this car, which is kind of obvious as he has yet to use it! With a long list of exotic cars parked in his garage this was always going to be his toy, a car that was custom built to his specifications, a dream that was turned into reality.

Ito-san got started on the stripped V-spec II N1 base chassis by strengthening weak areas with custom fabricated plates and lots of spot welding. You can see the boxed off areas around the front wheel arches, which have even been cut in order to stiffen the turrets and allow the custom suspension layout to fit. Custom engine mounts were created to position the engine a massive 20 cm rearward and a few centimeters lower, to help shift some of that heavy front end weight balance towards the center of the car. This might sound like as simple thing to do but due to the unusual oil-sump & differential housing layout of the RB26…

…a lot of work was required to keep the front drive shafts in line with the wheel hubs. This led to a custom sump being created with the main reservoir section moved rearwards. This also required a custom oil pick up and baffling to be designed and fabricated. The weigh balance benefits made all of this work worthwhile. But from the above shot you can clearly see the custom work didn't exactly end there! Hiroya-san called in the help of suspension specialists Ikeya Formula who were asked to create a custom adjustable suspension links. Up front the multilink set-up was replaced by a sort of double wishbone layout, which in turn needed custom mounting points on the chassis. Ito-san took care of the upper mounts when reinforcing the suspension turrets, while the lower mounts called for a whole new tubular sub-frame to be created. 

Adjustable stabilizers were also designed and the stock steering rack had to be moved back, so Ikeya Formula also needed to make pivots and pillow-ball tie rods, which you can see in the above picture. The race-spec Quantum dampers complete the transformation.

Any old brake kit wasn't going to cut it so Ito-san fitted Brembo Racing magnesium-alloy 6-pot monobloc calipers. This top of the line system, usually found in GT cars, uses lightweight titanium pistons. The 2-piece ø380 mm rotors and billet caliper mounts were made by Rdd.

At the rear ø355 rotors are employed along with 4-pot Brembo Racing calipers of the same quality as the fronts. Above its possible to see the custom work that has gone into creating and stiffening the wheel arch and suspension turret, and how most of the rear chassis section has been removed.

Like at the front, the rear stock subframe was eliminated and replaced with a custom tubular one fabricated to allow the double wishbone layout to be fitted. Ikeya Formula also made up adjustable stabilizers for the rear.

Shaving weight off was a big priority and almost 400 kg were removed thanks to all the custom suspension and chassis work, not to mention the dry-carbon body. Everything you see is custom made, every panel weighing in at a few kg, including the doors, where a great deal of the weight was removed from. Even the headlights were eliminated! The massive front spoiler is there to help generate lots of front downforce…

…with the rear end being sucked down by the diffuser, as well as pushed down by the massive carbon wing which is directly mounted onto the chassis. Wheels are of course Rays Engineering TE37s, 10J by 18-inch and wearing Yokohama Advan A048 tires in 265/35/ZR18 size at all four corners.

With the engine having been pushed back 20 cm the whole driving position was also shifted rearward, including the pedals and the extended steering column. The interior is really pure race car, the central tunnel custom built to offer more rigidity and house the 6-speed Hollinger sequential transmission. The Recaro SP-A sits in line with the B-pillar just like it would on a Super GT car and there is only one piece of instrumentation, a Motec data logger LCD display unit fixed onto the dry-carbon dashboard. The roll cage is pretty hardcore as you can see.

These are the two levers that adjust the front and rear stabilizers.

The HKS T04Z was chosen for the engine build, as it would have no problem supplying the 650 HP Ito-san and Hiroya-san were shooting for.

When I shot the car in the summer of 2007 the engine wasn't yet fully connected up with all the various piping and ancillaries, which was kind of cool as it was easy to see all the little details that make this one hell of a special BNR34! Notice how the custom ARC intercooler sits behind the radiator (another one-off ARC item), there to help give the best throttle response possible seeing how short the titanium piping could be kept in such a configuration. The HKS Step III 2.8L engine is built around an RRR block, known as the GT Block as it was used on the GT500 racing GT-Rs years ago. The HKS 272º cam on the exhaust side is joined by a V-Cam system on the intake which should make the engine develop lots of mid-range torque for optimal response and explosive acceleration.

The titanium exhaust is obviously custom, and a little on the short side (who said exhaust need to be long!) ending up pretty much where the transfer box ends. Along with the Hollinger, other driveline components include front and rear ATS carbon LSDs and an Exedy triple plate carbon clutch. All mounts for the gearbox and transfer box had to be custom made.

The men behind this incredible project, Hiroya-san on the left showing his target times for Tsukuba, Fuji, Suzuka, Central and Okayama and Ito-san, the man responsible for actually building this GT-R. Since 2007 I have waited in anticipation to see this car go up against the best Japan has to offer at the Super Lap Battle, but for three years now I have been disappointed. Hiroya-san has been busy making sure ProStock Racingcontinues to grow, which is probably why the BNR34 Time Attack project has been put on hold. I heard the car is on display at the ProStock HQ so I might have to drop by one of these days to find out when we can expect to see this beast in action! 

-Dino Dalle Carbonare

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