What Makes the 2JZ Engine So Good? (Explained)
Updated: Feb 2
✔ This article has been fact checked.
The 2JZ engine is regarded as the king of engines among automotive tuners. It was built to very high standards like no other engine, it has immense tuning potential and a brilliant history behind it.
Table of Contents:
What Is the 2JZ Engine?
A number of inline six-cylinder engines make up the Toyota JZ engine family. It served as the M-series inline six-cylinder engines' successor.
Dual overhead cam (DOHC) engines with 24 valves made up the JZ series.
The 2JZ engine had a bore and stroke of 86mm x 86mm and a 2,997 cc displacement, making it a "square" engine due to its 1:1 stroke-to-bore ratio.
There are several variations of this engine, with the 2JZ-GTE being the most popular. In Japan, the GTE version produced 280 horsepower, but in Europe and the USA, it produced 320 horsepower.
History
In 1978 Toyota wanted a car that would compete with Nissan's hugely successful 'Z' car.
They took their current Celica and gave it a cosmetic overhaul because they didn't feel like building a completely new platform.
They gave it the name Celica Supra and stuffed an inline six-cylinder under the hood. The name made more sense back then, despite the fact that it sounds funny today.
"Supra" refers to anything that is beyond and beyond its normal bounds, and the Celica Supra was just that. The standard Celica couldn't handle it.
The Celica Supra made more sense in the late 1970s since it had greater power, was bigger, and looked different.
Although it didn't manage to match the Nissan Z's sales numbers despite being a rather desirable vehicle, it did accomplish something historically noteworthy.
It established the connection between the inline six-cylinder engine and the name "Supra".
The Supra Celica received an inline six-cylinder engine as opposed to the Celica on which it was based, which had a four-cylinder engine.
Three years later, Toyota released their "M" engine, and the 80s design era soon followed, leading to a revamp of the complete Celica series.
The Celica Supra is also part of the second-generation automobiles, which are probably more different from one another than the first-generation vehicles.
The second-generation Celica Supra still had many parts in common with the original Celica while having a significantly different exterior and interior.
It sported an inline six-cylinder, was bigger, more opulent, and had superior equipment, yet it was still a Celica.
Currently, the term "Celica Supra" is still used everywhere, with the exception of Japan.
In Japan, the Celica Supra's first and second generations were both referred to as the Celica Double X.
The second-generation Supra accomplished another significant feat by being the first Supra to use turbocharging.
A momentous event occurred in February 1986 when the term "Celica" was removed off the Celica Supra. The Celica and Supra were now two distinct models, and they took various paths.
The Supra would continue to be rear-wheel-drive, but the Celica would go to front-wheel drive.
The Supra now used the Toyota Soarer platform and was no longer mechanically related to the Celica.
The Supra had greater capacity to expand because to the Soarer's larger platform. Toyota would create the Supra into a real performance vehicle on the bigger chassis.
The suspension of the Supra was improved with:
A double-wishbone system.
Three-channel ABS and TEMS (Toyota-electronically-modulated-suspension), which provided variable dampening.
The third-generation Supra gets the most advanced version of the "M" series of engines for its powertrain.
These 7M engines raised displacement to 3 litres, a measurement that would come to be associated with the turbocharged supra model.
Despite having a weak head gasket, the 7M-GTE engine produced very amazing power, making the Supra a true high-performance car.
In addition, the third-generation Supra was significant since it was the first Supra to have a 1JZ.
Only the third version of the Supra, which used the 1JZ engine to replace the 7M engine, was made available in Japan.
It provided a snapshot of the Supra's potential future, and in 1993, we would learn exactly how magnificent that potential would be.
The fourth-generation Toyota Supra went into production. It followed the previous generation's lead but was so much more.
Toyota went all out and utilised all of its over-engineering abilities from the 1990s to produce a truly stunning car for the fourth generation Supra.
The brand-new 2JZ engine, which appeared to be quite similar to the 7M engine on paper, was located under the hood.
The only similarities between these two engines are that they were both 3-liter inline six-cylinder engines with both normally aspirated and turbocharged variations.
The 2JZ was a power unit with considerably more potential, and only time would reveal how substantial that potential was. It would not just remedy the small faults that the 7M had.
The fourth-generation Supra managed to be over 100 kg lighter than the previous generation despite having better safety features, bigger brakes, bigger wheels, an additional turbo, and a number of other things.
Toyota reduced the weight of the Supra by using aluminium and magnesium alloys in a variety of structural components.
The Supra had a 0-60 time of slightly over 4.5 seconds and a quarter-mile time of 13.1 seconds.
Unfortunately, the fourth-generation Supra was only produced for a short time.
The fourth generation's manufacturing was abruptly put to a stop by a rising yen and a declining high-performance automobile market.
It was over in 1996, sales ceased in Canada in 1998. It would continue for a another four years in Europe and the USA. In Japan, the supra's era eventually came to an end in 2002.
The mk4 Supra's replacement wouldn't come for another 20 years. There is a case to be made that those two decades were more important for the Supra and the 2JZ engine than the years it was in production.
The world fell in love with the Supra and its amazing engine, which was capable of incredible power, after the 2001 release of the fast and the furious movie.
The 2JZ's power output was pushed in the early 2000s by tuners all around the world, although the early tuning was crude.
It was confusing since you required three distinct ECUs for three different purposes.
The 2JZ and Supra aftermarkets started to develop quite quickly, and soon it provided tuners with the resources they needed to determine the 2JZ engine's limitations.
However, it appeared that the 2JZ did not have a limit. Triple-digit horsepower soon became the standard and anticipated, and doubling the engine's horsepower appeared too simple.
Any less was disappointing. Incredibly high power outputs from engines using more stock components than anyone anticipated were recorded on dynos across the world.
Long before Toyota revealed the 2JZ as the replacement for the supra, the mythology of the 2JZ was already established.
Toyota unveiled the fifth-generation Supra in 2019, and with it, disappointment reverberated throughout the globe.
Supra enthusiasts anticipated a 2JZ successor that would follow in the footsteps of the 2JZ.
Instead, a BMW engine was used, and despite the fact that both the new engine and the car itself are excellent, enthusiasts weren't pleased.
If this isn't proof of how amazing the 2JZ is, then nothing is. Soon, people began insisting that the 20+ year old engine be put into the new Supra.
Design of the 2JZ Engine
Let's now examine the 2JZ's anatomy in detail and see why it makes such a fantastic engine.
A pair of overhead cams
Block with closed deck and oil return channels
Cast hyper-eutectic pistons under high pressure
Compression ratio of 8.5:1
Connecting rods made of steel
Fully balanced forged crankshaft
Head gasket made of multi-layered steel (MLS)
heavily strengthened bottom end and engine block
Inline six-cylinder engine with perfect balance
Thermal and friction-reducing internal oil gallery pistons
The inline 6-cylinder 2JZ engine is exceptionally balanced, as are all inline-6 engines.
Primary and secondary forces inside inline-six engines are properly balanced since an inline-six is really two inline three-cylinder engines that have been mirrored and joined.
The inline six-cylinder engine is exquisitely smooth, unlike other V6 engines which might experience an imprecise rocking moment between the cylinder banks.
Optimal balance allows you to rev it faster, longer, and safer, which gives the perfect foundation for increasing power output.
The Toyota 3S-GTE engine has two less cylinders than the 2JZ engine but is otherwise comparable.
Both engines are "square", sharing the same diameter and stroke as the 2JZ. Due to its square shape, they all feature a 1:1 bore-to-stroke ratio.
Additionally, the intake and exhaust valves, which have respectable sizes, are identical.
Power and torque are often balanced in square engine designs, and the 2JZ is a great example of one that succeeded in doing so.
Next, let's address the engine block, a topic that is frequently brought up in relation to the 2JZ engine.
Due to its closed-deck, cast-iron block construction, the 2JZ has a good reputation. This is correct, but it's just a partial justification.
We all know that there are several inline six-cylinder cast iron engine blocks available. The great majority of them are unable to perform the functions that the 2JZ engine block can.
We must examine the structure of the 2JZ block in further depth in order to see why it is so powerful.
Let's contrast it with another inline six-cylinder closed-deck cast iron engine block.
An excellent illustration is the 7M engine block from a 7M-GTE turbocharged engine, which was the 2JZ's forerunner.
The 7M engine block is a solid one and can handle some power, but it can't handle as much as the 2JZ.
There is a lot more reinforcing in the 2JZ. On its engine block, the enormous, noticeable reinforcement rods are visible pretty much everywhere.
As you can see, the reinforcing rods on the 7M block are not nearly as prominent as those on the 2JZ.
Let's now contrast the 2JZ and 3S engines.
As you can see, one half of this 3S-GTE engine block does feature substantial reinforcing rods, while the other half does not.
Large strengthening rods are included on both sides of the engine block of the 2JZ. Actually, oil return holes are employed with these reinforcing rods.
These are oil return holes, and the 2JZ has a lot of them, as can be seen when looking at the block from above.
This is a useful function because oil return is crucial to an engine and can create a variety of issues if not handled properly.
When the engine is operating at full load, problems like oil starvation might arise if there is an improper oil return.
For two reasons, the oil return holes on the 2JZ have been relocated outside of the engine block deck's primary perimeter.
To leave the block with more material
To serve as strengthening rods
It's a good idea to have more material in the engine block. Although it adds to the weight, obtaining a more durable engine block that can handle higher power makes the extra 5 kg not a significant concern.
The oil return holes are beyond the deck's perimeter for a second reason: they were employed as reinforcing rods.
One of the most extensively fortified engine blocks ever produced is the 2JZ engine block. You get something that is almost unbreakable.
The major journals of the crankshaft and the main bearing covers are also enormous. They are substantial and incredibly sturdy despite not being cross-bolted as in some other engines.
All of this explains how tuners are able to increase the 2JZ engine block's power to incredible heights.
Toyota also created a girdle that is bolted to the oil pan and the underside of the block. The engine block's bottom end is further reinforced by this girdle, which adds to its stiffness and durability.
The cylinder head gasket, which is located on top of the engine block, is made of three layers of multi-layer steel (MLS).
This head gasket marked a significant improvement over the fiber-based head gasket used in the 7M-GTEs.
The engine's internals are strong, and the crankshaft is made of completely counterweighted forged steel and has exceptionally durable journal bearings.
Like the crankshaft, the connecting rods are forged and strong as well.
The 2JZ's naturally aspirated generation engines with variable valve timing are the only ones that have somewhat flimsier connecting rods.
The pistons are high-pressure cast hypereutectic pistons rather than forged pistons.
Toyota had strong manufacturing and quality control in the 1990s. Although these pistons are not forged, they are still sturdy, well-made, and of consistently high quality.
Despite being cast, they can withstand this engine's 700-800 horsepower.
These pistons have a thermal coating on the piston crown in addition to a friction-reducing coating on the skirt.
These pistons include an interior oil gallery, which is another distinctive quality that can only be found in turbocharged 2JZ engines.
Along with the oil squirters found in the 2JZ turbocharged engine block, this internal oil gallery is connected.
These oil squirters directly squirt oil into the piston's oil gallery and onto the piston's bottom, which lessens the likelihood of knocking by cooling the piston crown.
In engines with natural aspiration, the compression ratio is greater.
Although low by today's standards, the turbocharged engines' 8.5:1 compression ratio is useful since it enables you to safely increase the boost pressure quite a little.
The 2JZ engine's cylinder head and the Toyota 3S-GTE engine's cylinder head have a lot in common.
Due to the fact that these engines have twin overhead cams, a timing belt is used to drive both cams.
Each cylinder has four valves, for a total of 24 valves on the 2JZ. The 2JZ has a rather broad valve angle of 45°.
In comparison to the 3S engine, particularly the initial generation of 3S engines, which featured Toyota's variable intake, the 2JZ's intake ports had a more contemporary look.
The 2JZ cylinder head does have good flow, and the engine's intake and exhaust ports are well-designed, although several inline six-cylinder engines from the same era may outperform the 2JZ in terms of flow.
It is often essential to slightly modify the ports and the head when tuners seek power improvements exceeding 800hp.
2JZ engines are of a non-interference design, which means the pistons and valves never share the same cylinder space.
The 2JZ has moderate camshaft specifications as a result of its non-interference design, but it is also great for engine safety.
2JZ-GTE JDM Stock Cam Specs:
Intake Duration: 224°
Exhaust Duration: 236°
Intake Lift: 7.80mm
Exhaust Lift: 8.41mm
2JZ-GTE Export Stock Cam Specs:
Intake Duration: 233°
Exhaust Duration: 236°
Intake Lift: 8.26mm
Exhaust Lift: 8.41mm
As you can see, this engine has a rather modest lift and mild duration. Changing the camshafts on the 2JZ engine is one of the simplest methods to increase power.
Sequential twin turbos are a feature of the 2JZ turbo version, meaning it has two turbos, one of which spools at low rpm and the other of which spools at higher rpm.
At about 4000 rpm, the second turbo begins to operate.
Sequential twin-turbo systems typically consist of one smaller and one bigger turbocharger, but both turbos on the 2JZ engine are the same size.
This sequential twin-turbo configuration produced a remarkably smooth power and torque curve.
Its 407nm of torque, which is accessible from 1800 rpm, is outstanding.
The 2JZ engine dates back to the 1990s, but we now have brand-new engines with comparable specifications. This alone demonstrates how excellent this engine is.
The 2JZ is also one of the few instances where the international market received a product that was more potent than the Japanese market.
In Japan the power output was limited to 280 hp, but about 320 hp in Europe and the USA. This limited horsepower was because of the 'gentleman's agreement' in Japan.
The fact that the 2JZ is fundamentally an overbuilt and overengineered engine with significant safety margins is a more important contributor to its success.
There are a few reasons why the engine was so overbuilt. The current state of the world economy was one of these causes.
Another factor was the reputation that Toyota and several other producers were attempting to establish in the 1990s.
The whole Toyota engine range benefited from the 1990s engineers being instructed to build things differently. Modern manufacturers are subject to substantially stricter safety, fuel efficiency, and pollution standards.
Due to these limitations, they are now required to produce light, efficient engines rather than the previously permitted massive, powerful iron engines.
Tuning Potential
The 2JZ engine is so strong that you can get between 700 and 800 hp with stock internals. Some people do this by installing one larger turbo.
Or, if you want to be a bit more creative, get two larger aftermarket turbos. This would allow you to have slightly different power and torque curves.
See the image below for an example of this.
Since most tuners utilise a big single turbo, it is probably the best option because it is less expensive and easier to tune.
You will need extra fuel after the large turbo, which calls for an aftermarket fuel pump and some larger injectors, often 900cc or 1000cc.
Higher horsepower figures can be achieved by replacing the cams to add a little more duration and lift.
To improve safety, it would be beneficial if you also replaced the valve springs with a stiffer type.
Then, all that would be left to do is swap out the side-mounted intercooler with a large front-mounted intercooler and swap out the existing ECU for a standalone ECU.
Is a 1000hp+ engine feasible? Yes, it is; but, it will also be far more expensive and difficult.
The standard pistons must be swapped out for some aftermarket forged ones. The standard rods would need to be swapped out with some aftermarket forged steel rods.
Around 1200–1500 horsepower may be supported by the standard crankshaft. Any power levels over this would necessitate considering a billet crankshaft.
The engine block itself is capable of sustaining thousands of horsepower, most likely 2000 horsepower or more. However, there are also billet engine blocks available.
A compound turbocharger configuration involves feeding a smaller turbo into a bigger turbo.
You get an even more insane power and torque curve as a result of the massive turbo forcing all of that compressed air into the engine.
You might want to upgrade your fuel injectors at this point to ones that are up to 2000cc. This would likely need two injectors for each cylinder.
You're going to need two or three fuel pumps to supply the necessary fuel pressure to these injectors.
You can see the 2JZ has massive power potential, even in stock form, which is why it is loved by tuners and automotive enthusiasts everywhere.
Sources
Wikipedia. "Toyota JZ Engine" https://en.wikipedia.org/wiki/Toyota_JZ_engine#2JZ
MotorTrend. Aaron Bonk. (Mar 4, 2020) https://www.motortrend.com/how-to/1505-guide-to-understanding-the-toyota-2jz-gte-engine/