All car enthusiasts, no matter how many generations pass, will always have a car in their hearts. They will always be looking, listening and telling stories about the previous generation of the legendary Toyota Supra, with its "diamond" engine that has left its own history in the world of tuning. But the question is, what makes this motor so good? Today TopSpeed.gr takes a little historical look back, trying to give an explanation as to why it's so special.
By Fotis GelamerisIt all started somewhere in 1990, when Toyota first introduced the JZ engine series. First released as the 1JZ-GE (1990-1995) in atmospheric form where it produced 170 horsepower at 6000 rpm. Then it wasn't long before another atmospheric version came along again (1995->) but this time with 200 horses and, of course, increased torque. The drive was, as in the whole JZ series, to the rear wheels. All models released with these engines were 4-speed automatics, with no manual option.
The supercharged version did not take long to come to light. The 1JZ-GTE, was fitted with two turbos (CT12A) arranged in parallel. With a static compression ratio of 8.5:1 , the power and torque quoted by the factory are 280 horses at 6200 rpm and 363 N-m respectively. The diameter and stroke remained the same as the 1JZ-GE : where it is 86mm x 71.5mm. Yamaha has had a... hand in the development and production of these engines (possibly the head design), hence the "Yamaha" markings on some engine parts. In 1991 the 1JZ-GTE was also fitted to the Soarer GT.
The very next, designated as the second generation 1JZ-GTE, combines the inherent smoothness of an inline 6-cylinder engine and timely power delivery via ceramic turbos. The ceramic turbo pulleys are prone to delamination under high rpm and localized temperature conditions; the first generations of 1JZs were even more prone to turbulence due to the presence of a faulty one-way valve on the header, especially on the intake cam cover causing gas to blow into the intake manifold. On the exhaust side, a decent amount of vapor flows into the turbos causing premature wear on the seals. The second generation engines have had this problem consistently and in Japan there has actually been a recall to repair the first generation engines, although this is not the case for 1JZs imported into other countries. The repair is simple and involves replacing the PCV valve (2JZ). All parts are available through Toyota.
It was not long before the third generation was released, more "searched" than the previous two. Introduced in 1996, still up to 2.5 litre turbo, but with Toyota's Beams architecture. This, included a rebuilt head, new valve timing mechanism (VVT-i) and improved cylinder cooling. The twin turbo was changed from a parallel (CT12A x2) to a single turbo (CT15B). This in part was more efficient, using smaller exhaust ports, where this allows the exhaust gases to have more velocity as they exit the head, which in turn spins the turbo faster and at lower rpm. Although the power numbers stayed the same (280 horses) the torque was increased by 20%. VVT-i technology and improved cylinder cooling helped the compression ratio go from 8.5:1 where it was to 9.0:1. These improvements helped fuel economy by 10%, and also low-end torque up to 50%.
A little mention should also be made of the lesser known member of the JZ family, the FSE. In 2000 or so Toyota introduced this engine model, where it was a direct fuel injection engine. Its purpose was to reduce fuel consumption and exhaust emissions without loss of performance. It used the same block as the 1JZ-GE, but with the cylinder head design being unique. It was a narrow angle cylinder head, with turbine control valves serving to improve combustion efficiency. The numbers it put up are impressive, with consumption being reduced by as much as 20%.
That was all well and good but the road to the creation of the "King of JZ" (and not only) had been opened. The reason, of course, for the 2JZ-GTE.
Initially, the engine was released in a "mild" version, called 2JZ-GE, where it was atmospheric with around 230 hp at 6000 rpm.It used Sequential Electronic Fuel Injection, had an aluminium head and 4 valves per cylinder, along with a cast iron cylinder block, with some versions using VVT-i.
After that, came the "overproduction".
The legendary 2JZ-GTE was now on the market. It didn't differ much from the existing 2JZ-GE, it just had some differences like turbines, better technology for piston cooling and a different head that allowed more power and torque. With a lot and a little, this engine managed to make 320 horsepower, which for 1993 was a big number. Its creation was intended to be Nissan's answer to the then new RB26DETT that had been released.
This is all well and good, but - and here comes the key question! How can it put out that much power without any problems? How can it be so reliable and "lift" improvement to a great extent, as it is... everyday to see Supra's with 2JZ's with horsepower of over 1,000 hp?
With the dual camshafts, which means 4 valves/cylinder for a better air/petrol mixture and better flow, as well as placing the spark plug on top for the best possible ignition. The existence of bucket style lifters, while not allowing the use of overly "wild" camshafts, does reduce the number of moving parts in the engine, thus contributing to increased reliability.
