The 1JZ and 7M-GTE are closely related to each other more than we know. The Toyota M series of engines came before the iconic 1JZ and 2JZ powerhouses. While the JZs enjoyed every bit of popularity, the Ms were left out of the spotlight and sidelined.
But, between these two, 1JZ-GTE and 7M-GTE, which are performance-based and turbocharged engines, can rise to the occasion and show their abilities when their performance is needed the most.
Let’s find out which engine fits the sleeper monicker and who’s lagging in terms of their capabilities.
With that, let’s start with the rundown of both of our engines.
The Toyota 1JZ-GTE
- Production Run: 1991 – 2007
- Cylinder Head Material: Aluminum
- Cylinder Block Material: Cast-Iron
- Configuration: Straight-Six
- Bore: 86 mm
- Stroke: 71.5 mm
- Valvetrain: DOHC with four valves per cylinder
- Displacement: 2.5 L (2492 cc)
- Compression Ratio: 8.5 and 9.0
- Weight: 450 lbs.
- Maximum HP: 276 HP at 6,200 RPM
- Maximum Torque: 280 lb-ft at 2,400 RPM
The Toyota 1JZ-GTE is the sporty and high-performance version of the 1JZ-GE engine. Though resembling the 1JZ badge, it is much related to its previous brother, the 7M GTE, than the 1JZ-GE.
1JZ-GTE is fitted with a monoblock cast-iron cylinder block with a specially cast structure that utilizes a seven-bearing support system. It has the same bore and piston stroke with the 1JZ-GE at 86 mm and 71 mm, respectively, and bigger bores than 7M-GTE.
The crankshaft has twelve balance weights and seven main journals which both of the pins and journals are induction-hardened.
The pistons are improved to withstand higher power output as well as to absorb varying temperature fluctuations during cycles. It is made of unique Aluminum casting, and each piston is fitted with a single oil ring and two compression rings.
The early generations of the 1JZ-GTE engine are not equipped with the variable valve timing, VVT-i, system. Toyota lowered the compression rating to 8.5. Furthermore, the second generation of 1JZ-GTEs engines is integrated with BEAMS technology, which has a higher compression ratio of 9.0 but is still lower than the 1JZ-GE.
The first generation 1JZ-GTE has a rated output of 276 HP at 6,200 RPM and 268 lb-ft of torque available at 4,800 RPM.
The initial release of the 1JZ-GTE engine utilizes the advantages of parallel-twin CT12A turbos, which are either blown through a front-mount air-to-air intercooler or on the side mount.
It is also worth noting that Toyota 1JZ-GTE engine strikes a fair balance of the aggressive smoothness attribute of a straight-six-cylinder with the high-revving capabilities and swift power delivery of the ceramic turbochargers.
However, due to their physical limitations, ceramic turbine wheels are brittle and more susceptible to delamination than their steel counterparts.
In the event of high impeller RPM speeds and local temperature conditions, this effect intensifies, usually due to higher boost pressures.
Also, following the initial release of 1JZ are first-generation 1JZ engines that experience more turbo failure due to a defective one-way valve on the heads, specifically on the inlet camshaft cover, causing the blow-by gases to be diverted into the intake manifold.
In addition, small to medium amounts of oil vapor go into the turbo that causes premature wear on the exhaust side seals.
This might be a mere design flaw, so it needs to be solved and be closed. So the succeeding generations or the second generation engines have this problem contained, and gladly, Toyota fixed it.
In the 200s, There was a recall campaign to repair the first generation engines in Japan. Fixing is simple and only involves PCV valve replacement, which is available on Toyota.
The final and third release of the 1JZ-GTE engines applied Toyota’s BEAMS architecture (Breakthrough Engine with Advanced Mechanism) introduced in late 1996.
Though it retained the 2.5 Liter displacement, it has better engine components, including the newly-developed continuous variable valve timing mechanism VVT-i.
A revamped head, better cooling, and ventilation of the cylinders through modified water jackets and newly-formed shims to reduce cam friction and coated with titanium nitride.
Toyota also changed the turbo setup in later releases from the twin parallel turbo switching to the single turbo CT15B. The single turbo bolted in the third generation 1JZ-GTE has smaller exhaust ports in the heads.
These are more efficient because this allows the outbound gases from the exhaust to gain more speed as they head to the exit, which in turn spools the turbo faster even at a lower RPM range.
The power rating third-generation 1JZ-GTE still stands at 276 HP but has higher torque at 280 lb-ft. It also has a higher compression rating of 9.0 due to adopting the new VVT-i upgrade and improved cylinder block cooling.
These revisions result in a better engine efficiency that reduces the fuel consumption to almost ten percent. The turbo replacement to the single from the twin also contributes to the fifty percent torque increase employed in this engine, even for low RPM speeds.
Applications of 1JZ-GTE Engine:
- Toyota Chaser/Cresta/Mark II 2.5 GT 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)
The Toyota 7M-GTE
- Production Run: 1986 – 1992
- Cylinder Head Material: Aluminum
- Cylinder Block Material: Cast-Iron
- Configuration: Straight-Six
- Bore: 83 mm
- Stroke: 91 mm
- Valvetrain: DOHC with four valves per cylinder
- Displacement: 2.5 L (2492 cc)
- Compression Ratio: 8.4
- Weight: 463 lbs.
- Maximum HP: 232 HP at 5,600 RPM
- Maximum Torque: 240 lb-ft at 4,000 RPM
The Toyota 7M-GTE is a member of the straight-six M series of engines. Toyota has produced M series of machines since 1965, and it undergoes several upgrades throughout the years in the industry.
The Toyota 7M-GTE is a turbocharged, water-cooled, 2.5 L gasoline engine. 7M-GTE is a performance-based type of engine, so the focal point and consideration when Toyota built this engine are prioritizing a better airflow and maximizing the power available.
This engine features a cast-iron cylinder block with a cast aluminum cylinder head. It is equipped with a CT26 Turbo with a ceiling of 6 psi maximal boost; and a fuel injection system that has been ahead in that period that made it stand out.
Applications of the 7M-GTE Engine:
- 1986 – 1992 Toyota Supra (MA70)
- 1986 – 1991 Toyota Soarer (MZ20/MZ21)
Engine Potential of 1JZ-GTE and 7M-GTE
If you put these two engines head to head and talk about their abilities, take them to the road. And there, since they are both performance-based engines, you can fairly say which produces more power in a particular RPM range.
1JZ has great internals, and that is because of its sporty profile. However, 7M-GTE is also a performance-based engine, but it will fall short of the power and torque production of the 1JZ; to add to that, 1JZ has stronger internals, leading us to their turbos.
These two have different turbos. In its initial release, the 1JZ is twin-turbocharged but later on, switched to a single one. The 7M-GTE wears a CT26 turbo.
The good thing about the CT15B turbo of the 1JZ-GTE is that it spools faster due to its smaller port that allows the exhaust gases to gain more velocity as they head to the exit.
The CT26 turbo spools slower, like the older turbos, and pretty much pumps hot air after 15 psi. But, it still keeps up by regulating the wheel temperature a little bit lower. And with that, you need to buy a compressor that can push a more extensive output for the CT26.
Problems Surrounding the Engines:
1JZ though not a perfect engine at all means but it delivers every time it goes out. Fair to say that 1JZ-GTE machines do not experience some issues that are associated with the 7M-GTE engine.
The problems of the 1JZ-GTE include rough idling, engine not starting, misfiring, and knocking sounds in the engine bay, which are all minimal and pose no serious risks that involve a complete overhaul.
On the other hand, 7M-GTE engine issues mainly lie in the failure of head gaskets that affects the bearings. Oil pressure also affects the cams; oil pumps tend to deteriorate in efficiency over time.
Summary
While it is true that 7M-GTE is not above the caliber of 1JZ-GTE in terms of reliability and overall durability of the engine, but it is worth knowing that the difference between the two is not miles apart.
Still, they are close enough to make them swappable to each other.
In addition to that, the cost is also a factor when swapping a JZ engine, since they are more popular hence harder to come by which deep-pocket guys can brazenly afford.
The more budget-friendly 7M-GTE who sits and waits for someone to pick it up has a lesser price than the 1JZ series but has almost the same engine potential. Which we can say that has a more power produced in the money that you spent on.
And with that, we can say that 1JZ produces more power and is more capable of absorbing those horses.
1JZ-GTE also has more resistance in occurring significant problems that is great in longer runs, especially for engines at this age. That is primarily due to its sturdy and robust internal components.
7M-GTE is not as strong as the 1JZ-GTE, and we mentioned it earlier. But one thing the 7M-GTE can assure all of us is that without the M series of engines, the JZ would not be as good as they are today. Talk about respect to the or