“The tuneable JZ series engine”
Picture #1 1JZ GTE
The first generation 1JZ engine did have a couple of issues, one was a faulty PCV one way valve on the cam cover that caused gases to flow into the intake manifold. Furthermore oil vapors into the exhaust manifold flowed onto the turbochargers causing shaft’s seals failure.
The first twin turbo 1JZ GTE had a cubic capacity of 2.5 liters, was also known for early head gasket problems. But the engine itself was not bad designed, instead the assembly specification were inadequate. The issue was that factory’s specification of the cylinder head bolts torque was not high enough. In fact because the bolts were tightened loose the gasket was prone to fail at around 75.000 miles. Another possible failure could only occur if the engine management system could have been modified for tuning purposes. The two “CT12A” ceramic turbochargers impellers could crack and delaminate if made run outside them efficiency range. In other words if more boost than standard specifications the two turbochargers could have also damaged the engine other than themselves. In 1996 the engine remained the same straight six, dual overhead camshaft 24 valves with the new VVT-I (continuously variable valve timing) and a reworked head. Also wider water jackets around the cylinders were designed but instead of two sequential turbochargers the new layout displaced only one (CT15B). The compression ratio gained 0.5 to reach 9:1. Gone the ceramic impellers and shaft in favor of more reliable steel components generated more lag and weight added by the new configuration. This engine in 1991 was very advanced in technology to the point that featured a coil ignition pack. The system was more precise than a conventional distributor cap at high rpms. The engine’s 86mm bore and 71.5mm stroke did feature a stroke short enough to safely reach 8.500 if not 9.000 rpms when remapped. The compression ratio was 8.5:1. Yamaha also contributed to the design of the cylinder head and part of the component assembly.
Finally in 2000 the 1JZ FSE received the upgrade of direct injection and consequently the compression ratio was now 11:1.
Vehicles that feature this engine were:
Picture #2 2JZ GTE
The first application of this engine was in the Aristo. Although had the same compression ratio as his predecessor, the turbochargers were steel ones. A cast iron block with aluminum cylinder head with a cubic capacity now enlarged to 3.0 liters and as the MKIII engine an Acoustic Control Induction System was installed in the inlet pipes to manage the compression. In European specification the 2JZ-GTE was capable of 321hp.
The sequential turbochargers now worked in sequence according to the performances required. The first small turbocharger work from 1800 to 3500rpm to minimize lag and maximize response generating 410Nm of torque at 1800rpm. Than at 3500rpm part of the pressurized exhaust gases are pre-directed to the big turbocharger to prepare it for the “takeover” phase at 4000rpm. From this point onwards the peak torque is achieved and maintained until the redline. The 2JZ GTE advanced engineering introduced the variable inlet cam timing and electronic throttle control. The 2JZ-GE with VVT-i technology reached 230hp thanks to the joint development of Toyota and Hitachi. Moreover the export version of the same engine was equipped with stainless steel turbine and impeller fins CT12B turbocharger impellors and more durable housings instead of the ceramic CT20 for the Japanese domestic market. Overall the 2JZ-GTE was a much better performance engine than the 1JZ-GTE because was improved to be more reliable and tuners knows that is an engine capable to withstand sky high power outputs from the standard form.
Vehicles that feature this engine were:
Edoardo Pandolfini Barberi 08/12/2013
Michael Knowling (2005) “The Toyota JZ engine guide” Autospeed [Online] available from:
[8th December 2005]
David Pratte (2010) “Toyota lesser known JZ engine” Modified [Online] available from:
[16th February 2010]
19bozzy92 (2013) “Toyota Supra 2JZ-GTE Accelerations” Youtube [Online] available from:
[12th Sept 2013]
Picture #1 [Online] Modified, available from:
Picture #2 [Online] Cartalk, available from: