The Toyota JZ engine family is a series of inline-6 automobile engines produced by Toyota Motor Corporation. As a replacement for the M-series inline-6 engines, the JZ engines were 24-valve DOHC engines in 2.5- and 3.0-litre versions.
1JZ
The 1JZ version was produced from 1990 to 2007 (last sold in the Mark II Blit Wagon and Crown Athlete). Cylinder bore and stroke is . It is a 24-valve DOHC engine with two belt-driven camshafts and a dual-stage intake manifold.
1JZ-GE
The 1JZ-GE is a common version, with a 10:1 compression ratio. Output for the early non-turbo, non-VVT-i (1990–1996) 1JZ-GE was at 6000 rpm and at 4800 rpm. VVT-i variable valve timing was added in 1995, for an output of at 6000 rpm and at 4000 rpm.
The 1JZ-GE shares most of its parts and exterior design with the later 2JZ-GE. The non-turbo, non-VVT-i 1JZ-GE is a non-interference engine.
Applications: Mark II Chaser Cresta Crown
Like all JZ-series engines, the early 1JZ-GE is designed for longitudinal mounting and rear-wheel-drive. All of these models only came with a 4-speed automatic transmission; no manual gearbox option was offered.
1JZ-GTE
The 1JZ-GTE is a twin-turbocharged version of the 1JZ, produced from 1990 to 2007. The first generation 1JZ-GTE employs twin CT12A turbochargers arranged in parallel and blowing through a side-mount or front mount air-to-air intercooler. With an 8.5:1 static compression ratio, the factory quoted power and torque outputs are at 6200 rpm and at 4800 rpm. The bore and stroke are the same as for the 1JZ-GE: bore × stroke is . In 1991, the 1JZ-GTE was slotted into the all-new Soarer GT.
The early generation 1JZ-GTEs combined the inherent smoothness of an inline 6-cylinder engine with the revving capacity of its short stroke and early power delivery of its small, ceramic wheeled turbochargers. The ceramic turbine wheels are prone to delamination in the setting of high impeller rpm and local temperature conditions, usually a result of higher boost. The first generation 1JZs were even more prone to turbo failure due to there being a faulty one-way valve on the head, specifically on the intake cam cover causing blow-by gases to go into the intake manifold. On the exhaust side, a decent amount of oil vapor flows into the turbos causing premature wear on the seals. The later second generation engines had this problem fixed. In Japan, there was a recall made in order to repair the first generation engines, however this does not apply to 1JZs imported into other countries.
The third generation of the 1JZ-GTE was introduced around 1996, still as a 2.5-litre turbo, but with Toyota's BEAMS architecture. This included a reworked head, newly developed continuously variable valve timing mechanism (VVT-i), modified water jackets for improved cylinder cooling and newly developed shims with a titanium nitride coating for reduced cam friction. The turbo setup changed from parallel twin turbo (CT12A x2) to a single turbo (CT15B). The single turbo is in part made more efficient by the use of smaller exhaust ports in the head, this allows the escaping exhaust gasses to have more velocity as they exit the head, which in turn, spools the turbo faster and at lower RPM.The adoption of VVT-i and the improved cylinder cooling allowed the compression ratio to be increased from 8.5:1 to 9.0:1. Even though the official power figures remained at at 6200 rpm, torque was increased by to at 2400 rpm. These improvements resulted in increased engine efficiency that reduced fuel consumption by 10%. The adoption of VVTi, a much higher efficiency single turbocharger than the twins as well as different manifold and exhaust ports were responsible for most of the 50% torque increase at low engine speeds. This engine was used primarily in Toyota's X chassis cars (Chaser, Mark II, Cresta, Verossa, Blit), the Crown Athlete V (JZS171) and in the later JZZ30 Soarer, as the JZA70 Supra had long been discontinued at this time.
Applications: Toyota Chaser/Cresta/Mark II 2.5GT Twin Turbo (JZX81) Toyota Chaser/Cresta/Mark II Tourer V/Roulant G (JZX90, JZX100) Toyota Mark II iR-V (JZX110) Toyota Mark II Blit iR-V (JZX110W) Toyota Soarer 2.5 GT-T(JZZ30) Toyota Supra MK III 2.5 Twin Turbo (R) (JZA70) Toyota Verossa VR25 (JZX110) Toyota Crown Athlete V (JZS171)
1JZ-FSE
Around 2000, Toyota introduced what are quite probably the least-recognized members of the JZ engine family: the FSE direct injection variants. These FSE 1JZ and 2JZ engines are aimed at achieving minimal emissions and fuel consumption together with no loss of performance.