TOYOTA SUPRA RZ-S JZA80 TUNING. TIME ATTAK PROJECT
Administrator World Garage
Thrill fans of high car fashion from land of rising sun! Japanese company JUN again took up old with even more enthusiasm, is ready to really surprise us.
While wave of racing's popularity for best lap time overwhelmed tuners from all over world, engineers from JUN Laboratory managed to complete total upgrade of one of their most legendary projects.
In completely new guise, with completely rethought improvements specifics, old, already forgotten by many Akira Supra returns to exorbitant speeds world. What is monster, who now has to defend his name on track is Tsukuba, we were able to find out at meeting with Watanabe-San from JUN. Just few days after installing modified engine back on car. Over long months, 2JZ-GTE has been painstakingly tuned for smoother power delivery. Now it is able to hit all those who persistently claims that JZA80 is not most suitable car for race track.
Initially, project was built by Koyama-San himself back in 2000, as very fast car for, track. She passed circle no Tsukuba Circuit all in just one minute, which was very good result for that time. Year later, car was completely rebuilt for top speed competition in Bonneville, was named JUN Akira Supra. Car was equipped with 1300 HP 2JZ-GTE engine with two Trust t78 turbines, custom-made aerodynamic body kit, which was designed to reduce air resistance. Creators of project hoped to beat their previous record of 419.4 km/h, set here 10 years ago on Nissan Z32 300ZX. However, result of Akira Supra is quite same — 401,2 km/h. After failure of car took place in far corner of Studio, only occasionally appearing at exhibitions, shows. year we decided to bring car back to life, but for other purposes, tasks. Together with demo company Impreza GRB Supra will participate in circuit races later season. Tuners from JUN realized that it was shame to leave such project gathering dust in walls of workshop.
Remains of former luxury
The body was originally prepared according to regulations of competition in Bonneville, which implies very strong safety frame welded to bearing part in numerous places, which is necessary to give structure rigidity, proper level of safety in event of an accident. With such an impressive backlog for further manipulation Supra required special attention to chassis, brake system, as racks tuners chose adjustable Zeal Super Function, complemented them with very rigid springs front, rear. From below body is also reinforced with several stretch marks, firmly welded to bottom, as is done on racing cars, all levers, rods are replaced by devices IKEA Formula, to get best handling. Responsible mission of slowing down car before turns is entrusted to mighty 4-piston calipers Alcon, working in tandem with no less impressive brake discs Grex, high-temperature pads Endless.
Power in numbers
The heart of car is still same 2JZ-GTE, which was operated by car in Bonneville, rebuilt on JUN Stroker kit with an estimated volume of 3.2 liters. Kit was developed quite long time ago specifically to work at high pressure, which could develop two snails Trust T78. So we are dealing with very strong bottom, which is an excellent base for further improvements. After installing turbine Trust T88-34D engine performance changed to achieve more suitable for track power, torque curves. Great attention was paid to cylinder head tuners, in particular boring, polishing channels to improve stability, as well as complemented design of internal adjustment washers, pushers valve springs from 3S-GTE, pushers were borrowed from legendary RB26DETT, which allows engine to unwind even faster.
The camshaft with an off-limit phase of 292° at outlet, finely tuned intake phases provide necessary ratio of stable engine operation at bottom, maximum power at high speeds. At stage of tuning, motor produces an invigorating 800 HP at 6900 rpm, peak torque is 6300 rpm, equal to monstrous 873 Nm. Cooled air to engine comes from 4-layer Greddy intercooler via larger diameter throttle from Nissan VH45, an intake receiver JUN. Next, air is mixed with racing fuel, which is supplied here with 6 SARD injectors, with capacity of 1000 cm^ / min, Bosch dual fuel pumps installed in trunk along with JUN anti-fuel tank. Proper motor's cooling level is provided by JUN radiator, together with two electric fans controlled by special block of Billion VFC. This, along with two oil coolers by Trust, allows to maintain operating temperature of engine even on hottest days on track. To cope with potential, properly distribute it on drive wheels. Tuners have installed sequential gearbox Holinger, 3-disc clutch HKS, TRD limited-slip differential.
The car's exterior was supplemented with same body kit that was originally developed for first project’s version, which has nothing to do with elongated model for racing in Bonneville. Front bumper provides necessary airflow to intercooler, oil radiators on sides, wide slot closer to hood line is used to cool radiator. To increase downforce on front axle. JUN engineers installed carbon fiber side splitters, lower diffuser on front bumper. In front fiberglass wings can be found special gills created to remove hot air from engine compartment. From these considerations, there appeared vented hood also made of fiberglass with small hill on right side, hiding huge turbine from prying eyes.
To achieve effective weight reduction tuners managed through use of carbon doors, trunk lid Fuji M Spec — perfectly made parts, completely repeating factory products' design. Side sills, rear bumper pads allow to achieve correct visual effect, more aggressive car’s landing, but aesthetics, as you know, is not important. It is much more important to ensure maximum adhesion of tires to asphalt, for him on trunk lid installed an adjustable wing made of carbon fiber, at bottom there was carbon diffuser, pair of side swirlers from there Amemiya catalog. As an alternative to wheels from previous Supra version tuners have chosen discs Yokohama Advan RG for front axle, RGII - for rear, wrapped in ultra-soft halves Yokohama Advan A050 M-compound. To give car more modern look, JUN designers have gone from branded yellow-green color scheme, chose sand-gray metallic with bright vinyl.
Before project will appear on tracks Tsukuba, Fuji, it has long way to painstaking settings, numerous tests required to achieve best results. Setting new records right off bat is not priority for car in near future, but JUN has every chance to prove to everyone how fast can be JZA80 on race track, we only have to wait for December, when on Tsukuba track once again will shine together best of best on Super Lap Battle .