Toyota JZ engine

Toyota JZ engine
Overview
Manufacturer	Toyota Motor Corporation
Production	1990–
Chronology
Predecessor	Toyota M engine

The Toyota JZ engine family is a series of inline-6 automobile engines. A replacement for the M-series inline-6 engines, the JZ engines were 4-valve DOHC engines. The JZ engine was offered in 2.5 and 3.0 liter versions.

1JZ-GE

The 2.5 L (2491 cc) 1JZ version was produced from 1990 through 2007+ (still in production with the Mark II BLIT Wagon). Cylinder bore was 86 mm (3.39 in) and stroke was 71.5 mm (2.81 in). It was a 4-valve DOHC engine with two belt-driven camshafts.

Output for the non-turbo 1JZ-GE was 200 hp JIS (147 kW) at 6000 rpm and 185 ft.lbf (250 Nm) at 4000 rpm.

Like all JZ-series engines, the early 1JZ-GE is designed for longitudinal mounting and rear-wheel-drive. All of these models also came with a 4-speed automatic transmission as standard; no manual gearbox option was offered.

1JZ-GTE

File:Firstgen1jzgte.jpg

First Generation 1JZ-GTE in Toyota Cressida

The 1JZ-GTE employs twin CT12A turbochargers arranged in parallel and blowing through a side-mounted air-to-air intercooler. With an 8.5:1 static compression ratio, the factory quoted power and torque outputs are 206kW at 6200 rpm and 363Nm at 4800 rpm respectively. These early 1JZ-GTEs are most commonly available with an auto transmission but a 5-speed manual version was available in the Supra 2.5 GT. Yamaha is believed to have had a hand in the development or production of these motors (possibly the head design), hence the Yamaha badging on certain parts of the motor, such as the cam gear cover and possibly the cylinders themselves.

In the following year (1991), the 1JZ-GTE was slotted into the all-new Soarer GT. Output remained at 206kW/363Nm and, again, most examples come tied to an auto trans. These 1JZ-GTE powered Soarers are quite common on the Australian market (as ‘grey’ imports).

The early generation 1JZ-GTEs are a great engine from a bang for buck point of view, combining 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. IMPORTANT: On that note, the 1st Gen 1JZ's 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 to go into the intake manifold. Also on the exhaust side a decent amount of oil vapor flows into the turbos causing premature wear on the seals. The later 1st Gens had this problem fixed and in Japan there was actually a recall in order to repair the 1st Gens, though that does not apply to 1JZ's imported to other countries. The fix is simple, and involves replacement of the PCV valve (2jz); all parts are available through Toyota.

The 3rd Generation of 1JZs were introduced around 1996, still as a 2.5 turbo, but with reworked head incorporating Toyota's new VVT-i (variable valve timing with intelligence) system. These engines also used a single CT26 turbo (revised from the old 7MGTE, as well as the 3SGTE) instead of twin CT12a turbos. The "official" power output of 206kw remained the same, however the torque output was markedly improved, up to 378Nm at only 2400rpm. This engine was used primarily in Toyota's X chassis cars (Chaser, Mark II, Cresta, Verossa) and in the later JZZ30 Soarer, as the JZA70 Supra was long discontinued by this time.

Applications:

• Toyota Chaser/Cresta/Mark II Tourer V (JZX81, JZX90, JZX100, JZX110)
• Toyota Soarer (JZZ30)
• Toyota Supra MK III (chassis code JZA70, Japan only)
• Toyota Verossa

2JZ

The 3.0 L (2997 cc) 2JZ has been produced since 1992 (first released in the 1992 Lexus SC 300). Cylinder bore was 86 mm (3.39 in) and stroke was 86 mm (3.39 in). VVT-i variable valve timing was added later in 1998.

2JZ-GE

The 2JZ-GE is a common version. Output is 215 to 230 hp JIS (158 to 169 kW) at 5800 to 6000 rpm and 209 to 220 ft.lbf (283 to 298 Nm) of torque at 3800 to 4800 rpm.

It uses Sequential Electronic Fuel Injection, has an aluminum head and 4 valves per cylinder with some versions using VVT-i, along with a cast iron cylinder block.

Applications:

• Toyota Altezza / Lexus IS 300
• Toyota Aristo / Lexus GS 300
• Toyota Crown
• Toyota Mark II
• Toyota Progres
• Toyota Soarer / Lexus SC 300
• Toyota Supra MK IV

2JZ-GTE

Engine bay of MK4 Supra

Development of the 2JZ-GTE was outsourced to German engineering firm, Johann A. Krause Maschinenfabrik GmbH, for refinement to meet production car homogolation requirements set forth by the former All-Japan Grand Touring Car Championship.

The engine's original intended use was to power the fourth-generation Supra JZA80 sports car. It's mechanical basis was the existing 2JZ-GE, but differed in its use of sequential twin turbochargers, an air-to-air, front-mounted intercooler, and uprated internal components.

The use of sequential twin CT12B turbochargers raised its power output from a mere 166 kW (225 hp DIN) to the industry maximum of 206 kW (280 hp DIN) at 5600 rpm, limited by Japan's (now defunct) "Gentlemen's Agreement" between Japanese automakers, although real output and torque figures were beyond the claimed values.

For the North American and European market, engine power was raised to 229 kW (310 hp DIN) at the same engine speed of 5600 rpm. The export version of the 2JZ-GTE achieved its higher power output due to different turbochargers (stainless steel for export models, ceramic for Japanese models), camshafts, and larger injectors (550 cc/min for export markets, 440 cc/min for Japanese models). Because the primary mechanical differences between the export (CT12B) and Japanese (CT20A) model turbines are the size and material of the exhaust-side shaft (stainless steel exhaust-side shaft for export models vs. ceramic shaft for Japanese models), one can replace the Japanese-specification turbine's ceramic shaft with the steel shaft from CT12B turbines of export models . In tuning groups, in spite of the lack of actuators for both turbines, the factory turbochargers are often retained after mild engine modification due to the highly durable housings and, for export vehicles, use of stainless steel for the impeller and turbo fins. In light of the above as well as the due to the use of forged crankshaft and connecting rods, and cast pistons, the 2JZ-GTE is well-known for requiring no internal modification to major reciprocating engine components to cope with the stress associated with ever-higher boost.

The 2JZ-GTE engine is popularized as the adversary to Nissan's RB26DETT with regards to flexibility, reliability, and aftermarket recognition in the automobile tuning niche.

Applications:

• Toyota Aristo (Japan-only)
• Toyota Supra JZA80

1.5JZ-GTE

The 1.5JZ is not a production engine but is created by combining a 1JZ with a 2JZ bottom end. The 2JZ bottom end will simply bolt onto the 1JZ cylinder head.

• 1JZ = 2.5L Inline 6 (86.0mm bore x 71.5mm stroke)
• 2JZ = 3.0L Inline 6 (86.0mm bore x 86.0mm stroke)

Using a 2JZ bottom end with the 1JZ components allows an extra 500cc of displacement.

Reasons for this conversion is a matter of opinion and discussion. Some claim a 1JZ head flows better than a 2JZ, however this is unfounded as of yet.

What is known is that the 2JZ head compared to the 1JZ head has more restriction in the 5th and 6th cylinder exhaust ports due to an S shaped casting. The 1JZ also has different shaped combustion chambers which, when directly placed on a 2JZ block, increases the compression slightly and leads to a power increase when using unworked heads. Once worked (ported and chambers reshaped, valves resized) the heads have been proven to flow much the same.

The most likely reason for the setup would be if the owner of a worked 1JZ engine suffered from bottom end failure or if they wanted the extra displacement and torque of the 2JZ bottom end, as the heads are interchangeable.

Direct Injection FSEs

In around 2000, Toyota introduced what are probably the least recognised 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.

The 2.5-litre 1JZ-FSE employs the same block as the conventional 1JZ-GE everything up top, however, is unique. The ‘D4’ FSE employs a relatively narrow angle cylinder head with swirl control valves that serve to improve combustion efficiency. This is necessary to run at extremely lean air-fuel ratios around 20 to 40:1 at certain engine load and revs. Not surprisingly, fuel consumption is reduced by around 20 percent (when tested in the Japanese 10/15 urban mode).

Interestingly, normal unleaded fuel is enough to cope with the FSE’s 11:1 compression ratio.

The direct injection version of the 1JZ generates 147kW and 250Nm – virtually the same as the conventional VVT-i 1JZ-GE. This highly efficient engine is fitted to the 2000 Mark II, 2001 Brevis, Progres, Verossa, Crown and Crown Estate. All are fitted with an automatic transmission.

The 3-litre 2JZ-FSE uses the same direct injection principle as the smaller 1JZ version but runs an even higher 11.3:1 compression ratio. This engine matches the conventional VVT-i 2JZ-GE with 162kW and 294Nm. The 2JZ-FSE is fitted to certain 1999 Crown models and the 2001 Brevis and Progres. Again, all use automatic transmissions.

These FSE engines are certainly very interesting from a technical perspective.

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See also

• List of Toyota engines
• Toyota Supra

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