This article will discuss the differences between the Toyota 1JZ and 2JZ engines.
We will go into depth on the mechanical differences between the two engines, their history and specifications.
We’ll also discuss which engine is better, their ability to be tuned and much more.
1JZ & 2JZ Engines
From the outside, they may look identical, but there are some significant differences between the 1JZ and the 2JZ.
The 1JZ engine was designed by Toyota engineers and assembled by Toyota Motors Manufacturing.
The engine’s design allowed for simplicity, reliability and maximum performance while being able to fit within the Supra’s long hood and short deck.
The 2JZ engine was also designed and assembled by Toyota Motors.
History of the 1JZ & 2JZ Engines
The third-generation Supra was significant for one primary reason; it was the first Supra to get a 1JZ.
In Japan, only the third generation of the Supra became available with the 1JZ engine, the successor to the 7M engine.
Toyota started production of the fourth-generation Supra, it continued on the path set by the previous generation, but it was so much more.
Because for the fourth-generation Supra, Toyota went all out and used all of its 90s over-engineering skills to create a genuinely spectacular car.
Under the hood was the brand new 2JZ engine; the 2JZ and the 7M engines seemed very similar on paper.
Both engines existed in naturally aspirated and turbocharged variants, and both engines were 3-litre inline six-cylinder engines, but that’s where the similarities end.
The 2JZ wouldn’t just fix the minor issues that the 7M had, but it was a power unit with a much greater potential, and only time would unveil just how significant that prospect was.
The 2JZ, and the 1JZ, is genuinely a fantastic engine.
You can read more about the 2JZ engine here.
Mechanical Differences Between the Engines
The 1JZ and 2JZ are very similar engines, the significant differences being the increased displacement in the 2JZ.
The 2JZ is now 3.0 litres instead of 2.5 litres like in the 1JZ.
While the 1JZ has a parallel twin-turbo setup, the 2JZ engine features a sequential twin-turbo setup.
In the 1JZ, there is one turbo for every three cylinders; in the 2JZ, both turbos pressurise all six cylinders.
The bore is the same in both engines, but the 2JZ has a longer stroke and a taller deck, making up for the larger displacement.
Camshaft
The 1JZ and 2JZ have different camshaft profiles.
- 1JZ-GTE Exhaust Cam: Peak ~7.98mm @ ~328Deg
- 1JZ-GTE Inlet Cam: Peak ~7.72mm @ ~34Deg
- 2JZ-GTE JDM Exhaust Cam: Peak ~8.67mm @ ~328Deg
- 2JZ-GTE JDM Inlet Cam: Peak ~8.08mm @ ~41Deg
There will be some minor disparities in the measurements of these cam profiles. Overall, it seems as though the 2JZ has a more aggressive cam profile than the 1JZ engine.
Internals
The 1JZ and the 2JZ have slightly different internals. If you pulled out the connecting rods from each engine, you would find that the 2JZ has longer connecting rods.
The stroke is also longer on the 2JZ, and the deck height has been increased.
The 2JZ engine is generally a more robust engine, able to handle around 800-900hp at its limit. 600-700hp is about the limit for the 1JZ engine.
Turbo
The first generation 1JZ-GTE employs twin CT12A turbochargers arranged in parallel. The pressurised air flows through a side-mount or front-mount air-to-air intercooler.
The 1JZ featured ceramic turbine wheels; however, they’re are prone to delamination with high impeller rpm and local temperature conditions, usually the result of higher boost pressure.
First-generation 1JZs were even more prone to turbo failure due to a faulty one-way valve on the head, causing blow-by gases to enter the intake manifold.
The 2JZ made use of sequential twin turbochargers and an air-to-air side-mounted intercooler. Toyota jointly developed these turbochargers with Hitachi.
2JZ engines didn’t seem to have the same fault as the 1JZ.
The 2JZ-GTE
Toyotas 2JZ-GTE launched in 1991, powering the Toyota Aristo V before finding its home in the JZA80 model Toyota Supra.
The 2JZ-GTE was Toyota’s response to Nissan’s wildly successful RB26DETT engine. It had the strengths of the 1JZ and built on them with a higher displacement and more advanced sequential twin-turbochargers.
The 2JZ has the same 86mm bore that the 1JZ has, but its stroke is increased from 71.5mm to 86mm.
Deck height has also been increased in the 2JZ, along with longer connecting rods. This stoke to bore ratio makes the 2JZ a square engine.
The 2JZ-GTE was praised by the Fast & The Furious movie franchise. 800-900hp is about the limit on standard internals for the 2JZ engine.
- Displacement: 2997cc
- Configuration: DOHC, 24 Valves
- Bore x Stroke: 86 mm x 86 mm (3.39 in x 3.39 in)
- Power: 280ps @ 5,600 rpm
- Torque: 320 lb ft @ 4,000 rpm
- Turbo: CT20 Turbine x 2
- Stock Boost: 11 PSI
The 1JZ-GTE
The 1JZ-GTE was produced by Toyota and made its appearance in the 1991 Soarer GT. Toyota opted for a turbocharged inline six-cylinder configuration; it had an 86mm bore and a 71.5mm stroke.
This engine went through several variations in its production, including changing to a more advanced head design in its final iteration using variable valve timing with intelligence (VVTi).
The latest version of the 1JZ-GTE also changed from the original twin turbocharger setup to a larger single turbo setup.
You could find this engine at the higher end of Toyota’s 90s car lineup, including the Soarer, the Supra and Tourer V variants of the JZX family.
The 1JZ is a popular engine commonly swapped into other vehicles and chassis due to its displacement, strong internals and vast aftermarket tuning support.
Some people believe that with the correct modifications, such as fueling, turbo and ECU, the stock engine can produce around 800hp.
Though 600-700hp is about the limit before the engine needs forging.
- Displacement: 2498cc
- Configuration: DOHC, 24 Valves, VVTi
- Bore x Stroke: 86 mm x 71.5 mm (3.39 in x 2.81 in)
- Power: 280ps @ 7,500 rpm
- Torque: 280 lb-ft @ 2,400 rpm
- Turbo: CT15B
- Stock Boost: 9 PSI
Differences in Performance
Both the 1JZ-GTE and the 2JZ-GTE have excellent reputations as engines capable of high horsepower and continued reliability.
Evidence of this is when professional drifters select their engines; they go for either the V8’s or the JZ family of engines found in the Supra.
Both engines are very similar on paper, but the increased displacement of the 2JZ-GTE provides the same level of power at lower rpm’s.
For this reason, the 2JZ-GTE has the advantage. Plus, the 2JZ is a newer engine, with time engines degrade and lose their tolerances.
Tuning Potential of the 1JZ and 2JZ
The 1JZ and the 2JZ both have heaps of aftermarket tuning potential. Especially the 2JZ.
You can swap out almost every part of the 2JZ engine with an aftermarket part; there are even billet engine blocks available on the market.
Overall, both engines are very, very tunable.
They are also very strong engines with colossal power potential, the 2JZ being slightly more robust and powerful.
Conclusion
In our opinion, we think the 2JZ is the superior engine of the 1JZ and 2JZ. The 2JZ is more robust, more powerful and more tuneable.
But, don’t be fooled, the 1JZ is a great engine. It just has slightly less power and strength.
The first-generation 1JZ was also prone to turbo failure. Overall, they are both exceptional engines, but the 2JZ takes the win.
