VC-Turbo Technology Explained in the 2025 Infiniti QX60: The Engine That Thinks It’s Two Engines
There is a moment of quiet amazement when you’re cruising down the highway in the 2025 Infiniti QX60, the family is settled in the second-row captain’s chairs, the Bose audio system is playing softly, and you realize the engine under the hood is physically transforming itself—changing its own internal geometry in real-time—to save you fuel without you ever feeling a thing.
If you are looking at the 2025 Infiniti QX60, you probably know it looks stunning. You might know it has that beautiful Semi-Aniline leather and those Zero Gravity seats that make road trips bearable. But the real story is what you cannot see. Under the hood, Infiniti has swapped the old 3.5-liter V6 for something far more advanced: a 2.0-liter VC-Turbo four-cylinder. This isn’t just a downsizing move. It is the world’s first production variable compression ratio engine, and it represents over 20 years of engineering obsession .
This engine does something no other production engine has ever done. It changes its compression ratio on the fly, ranging from 8:1 for high performance to 14:1 for maximum efficiency . It is like having a sports car engine and a hybrid engine in one package. Let’s pop the hood and look at the mechanical wizardry inside.
TL;DR
The 2025 Infiniti QX60’s new VC-Turbo engine uses a complex multi-link system to physically raise or lower the pistons’ reach, changing the compression ratio seamlessly between 8:1 and 14:1 . This allows it to deliver 268 horsepower and 286 lb-ft of torque (more torque than the old V6) while improving fuel economy to 24 mpg combined . The technology eliminates the traditional trade-off between power and efficiency. However, some reviewers note the engine feels less responsive from a stop than the V6, and a recent recall affects earlier versions of this engine in other models .
Key Takeaways
- Variable Compression Explained: The engine uses a harmonic drive actuator to pivot a control shaft, changing the piston’s top dead center position and therefore the compression ratio .
- Power and Efficiency: Output is 268 hp and 286 lb-ft, with fuel economy improving to 24 mpg combined with FWD .
- How It Feels: The new engine delivers strong mid-range torque but can feel lethargic off the line due to the transmission’s eco-biased tuning .
- Award-Winning Tech: The VC-Turbo engine won WardsAuto 10 Best Engine awards in 2019 and 2020 .
- Reliability Context: A 2025 recall affects earlier VC-Turbo engines (2019-2022 models) for bearing failures, but newer engines have manufacturing updates .
The 20-Year Quest: Why Variable Compression Matters
To understand why the VC-Turbo is such a big deal, you have to understand the fundamental compromise in every other engine on the road.
The Fixed Compression Ratio Problem
Every traditional gasoline engine has a fixed compression ratio. Engineers have to choose one number, usually somewhere between 8:1 and 12:1. This is a compromise. A high compression ratio (like 12:1) squeezes the air-fuel mixture tighter, which is great for efficiency and power. But under boost from a turbocharger, high compression causes knocking (detonation) that can destroy the engine.
A low compression ratio (like 8:1) allows for lots of turbo boost and high power without knocking, but it is inefficient during normal cruising when the engine isn’t under boost.
For a century, engineers accepted this compromise. Infiniti decided to fix it.
“VC-Turbo does not optimize around a fixed compromise. It adds mechanical freedom so the engine can adapt its behavior in real time.” – Saeid Moradi Zadeh, Powertrain Engineer
The Breakthrough
Infiniti’s engineers spent over 20 years developing a solution. They created a multi-link system that physically changes how far the pistons travel up and down the cylinders . By moving the position of the piston’s top dead center, they could change the clearance volume—the space left at the top of the cylinder when the piston is at its highest point .
This changes the compression ratio. And they did it in a way that works seamlessly, at engine speed, without the driver ever noticing.
How the VC-Turbo Engine Actually Works
Let’s get into the mechanical details. It sounds complicated because it is, but the core idea is brilliant.
The Multi-Link Mechanism
Instead of a traditional connecting rod bolted directly to the crankshaft, the VC-Turbo uses a complex multi-link system . Think of it as a small, internal robot arm. Key components include:
- Harmonic Drive Actuator: A powerful electric motor that drives a control shaft .
- Control Shaft: A shaft running the length of the engine with eccentric cams.
- Multi-Link Arms: These connect the piston to the crankshaft via the control shaft.
When the actuator rotates the control shaft, it changes the angle of the multi-link arms. This raises or lowers the entire range of piston motion .
The Two Modes (And Everything In Between)
The engine can continuously adjust between two extremes:
High Performance Mode (8:1 Compression):
- The control shaft moves, lowering the piston’s top dead center position slightly.
- This creates more clearance volume at the top of the cylinder.
- Compression ratio drops to 8:1.
- This lower compression allows for higher turbo boost pressure without knocking.
- The engine feels powerful and responsive .
High Efficiency Mode (14:1 Compression):
- The control shaft rotates the other way, raising the piston higher in the cylinder.
- Clearance volume shrinks.
- Compression ratio soars to 14:1.
- This extreme compression squeezes maximum energy from every drop of fuel.
- The engine runs efficiently, like a diesel .
In between, the engine picks any ratio it needs. Accelerating onto a highway? It might be at 9:1. Cruising gently? It slides toward 14:1. It happens continuously, not in steps .
Supporting Technologies
The VC-Turbo doesn’t work alone. It uses several supporting systems to make this magic happen:
- Dual Fuel Injection: The engine uses both direct injection (for power) and port injection (for efficiency and cleaning intake valves). In low-compression mode, the system uses port injection for cooler, more powerful combustion. In high-compression mode, it switches to direct injection for precise control and to prevent knock .
- Dual Combustion Cycles: The engine can run on the traditional Otto cycle for power or switch to the Atkinson cycle (which holds the intake valve open longer) for efficiency, mimicking hybrid engines .
- Mirror-Bore Coating: The cylinder walls are coated with a special material that reduces friction by nearly 50%, helping the engine spin freely and save fuel .
The Numbers: Power, Torque, and Fuel Economy
So what does all this mechanical complexity deliver in the real world?
| Metric | 2025 QX60 VC-Turbo | Previous QX60 3.5L V6 | Change |
|---|---|---|---|
| Horsepower | 268 hp | 295 hp | -27 hp |
| Torque | 286 lb-ft | 270 lb-ft | +16 lb-ft |
| Fuel Economy (FWD) | 24 mpg combined | 23 mpg combined | +1 mpg |
| Fuel Economy (AWD) | 23 mpg combined | 22 mpg combined | +1 mpg |
The horsepower number dropped, but torque—the feeling of “pulling power” you feel when you accelerate—went up. Torque peaks lower in the rev range, which should make the car feel stronger in everyday driving .
However, real-world testing by reviewers showed slightly different results. One test over a 73-mile loop returned 23.5 and 23.3 mpg in an AWD model, slightly under the EPA’s 24 mpg rating . The previous V6 actually beat its EPA rating in the same test, so the real-world improvement may be smaller than advertised .
Driving Impressions: What the Reviewers Say
Numbers on a page are one thing. How does the engine actually feel when you drive it?
The Good: Mid-Range Punch
Once the 2025 QX60 gets moving, the VC-Turbo delivers. The 286 lb-ft of torque provides solid passing power on the highway. Reviewers note that the engine pulls strongly once you are underway and the revs climb . It feels muscular and capable for merging and highway cruising.
The Not-So-Good: Low-Speed Lethargy
Here is the biggest complaint from automotive journalists: off-the-line response. The QX60 feels sluggish from a dead stop . There are a few reasons for this:
- The Engine: The VC-Turbo, despite its torque advantage, doesn’t feel as eager at low RPMs as the old V6.
- The Transmission: The 9-speed automatic is programmed for efficiency. In Normal mode, it upshifts very quickly, keeping the engine in a low-RPM range where it feels sleepy .
- The Weight: The QX60 is a heavy three-row SUV. A small-displacement four-cylinder has to work harder to get it moving.
The Fix: If you select Sport mode, the transmission holds lower gears and the engine feels much more responsive. Of course, that comes with more engine noise and lower fuel economy . It is a trade-off.
“I found the VC-Turbo powertrain less responsive from a dead stop than the previous V6.” – Jim Resnick, Capital One Auto Navigator
The Elephant in the Room: The Recall
If you are researching the VC-Turbo engine, you have probably seen headlines about a major recall. Let’s address it directly.
What Happened?
In mid-2025, Nissan issued a recall for nearly 450,000 vehicles equipped with VC-Turbo engines . The recall covered:
- 2019-2022 Infiniti QX50
- 2022 Infiniti QX55
- 2021-2024 Nissan Rogue (1.5L 3-cylinder version)
- 2019-2020 Nissan Altima
The Problem: A manufacturing defect in the multi-link mechanism could cause bearing failures. If the bearings fail, it can lead to catastrophic engine failure . The recall involved inspecting oil pans for metal shavings. If metal was found, the engine was replaced. If not, the oil was changed . A class-action lawsuit was later filed, alleging the engines can fail dramatically even after the recall fix .
Does This Affect the 2025 QX60?
The recall specifically covers vehicles up to the 2022 model year for Infiniti. Nissan has stated that they introduced manufacturing updates over the life of the engine, which seem to have solved the problem . The 2025 QX60 uses a newer iteration of the VC-Turbo engine with these updates.
However, it is worth knowing the engine’s history. If you are considering a 2025 model, the risk appears to be significantly lower. But it also highlights the complexity of this engine—there are more moving parts, which means more potential points of failure.
VC-Turbo Technology Comparison
To help you visualize how the VC-Turbo compares to traditional engines and itself across its operating range, here is a breakdown.
| Aspect | VC-Turbo Engine | Traditional V6 |
|---|---|---|
| Compression Ratio | Variable (8:1 to 14:1) | Fixed (e.g., 10.5:1) |
| Power Delivery | Boost-dependent, mid-range torque | Linear, predictable |
| Fuel Economy | Optimized for cruising | Consistent but compromised |
| Complexity | High (multi-link, dual injection) | Low (proven design) |
| Best Use Case | Mixed driving with highway cruising | All-around performance |
The VC-Turbo engine eliminates the need for balance shafts because its multi-link kinematics naturally reduce secondary vibration forces .
FAQ: Your 2025 Infiniti QX60 VC-Turbo Questions Answered
What does VC-Turbo stand for?
VC-Turbo stands for Variable Compression Turbo. It refers to the engine’s ability to change its compression ratio while running .
How does the VC-Turbo engine work?
It uses a multi-link system connected to a control shaft. An actuator rotates the shaft, changing the piston’s top dead center position and therefore the compression ratio . It adjusts seamlessly between 8:1 and 14:1.
Is the 2025 QX60 faster than the old model?
The new engine has less horsepower (268 vs 295) but more torque (286 vs 270 lb-ft) . Off-the-line acceleration feels slower due to transmission tuning, but mid-range passing power is improved.
What is the fuel economy of the 2025 QX60?
EPA ratings are 24 mpg combined with front-wheel drive and 23 mpg combined with all-wheel drive . Real-world testing has shown slightly lower numbers, around 23.5 mpg .
Is the VC-Turbo engine reliable?
The engine is complex, and early versions (2019-2022) were subject to a major recall for bearing failures . Nissan introduced manufacturing updates for newer engines, and the 2025 model uses these updated components. However, a class-action lawsuit has been filed alleging ongoing issues .
Why did Infiniti replace the V6 with a four-cylinder?
The primary reason is fuel economy and emissions. The VC-Turbo delivers better EPA ratings and lower CO2 emissions while maintaining similar real-world performance for most drivers .
Does the VC-Turbo require premium fuel?
Infiniti recommends premium fuel for optimal performance, but the engine can run on regular with reduced output. Check your owner’s manual for specific recommendations.
How does it sound compared to the V6?
Reviewers note the VC-Turbo can feel “coarse through a wide span of engine speeds” compared to the old V6, which was smooth but buzzy under hard acceleration . It is a different character—more modern but less refined.
The Final Verdict: A Glimpse Into the Future
The 2025 Infiniti QX60’s VC-Turbo engine is a marvel of engineering. It represents over two decades of work and solves a problem engineers have wrestled with for a century. In theory, it offers the best of both worlds: the efficiency of a small diesel and the power of a boosted gasoline engine.
In practice, it is a more complicated story. The engine delivers on fuel economy and mid-range torque, but it loses some of the off-the-line urgency and smoothness of the old V6. It feels like a compromise—a very advanced compromise, but a compromise nonetheless.
For the average family buyer, the VC-Turbo will be just fine. It gets you where you need to go, saves a bit at the pump, and the complexity is hidden beneath the hood where you never have to think about it. For enthusiasts who loved the old V6’s character, it might feel like a step backward.
Either way, the VC-Turbo is a fascinating piece of Japanese luxury engineering that proves the internal combustion engine still has new tricks to teach us.
What’s your favorite hidden feature inside your Infiniti? Share your thoughts in the comments below. (Or tell us: would you miss the V6, or does the new tech win you over?)
References:
- 2025 Infiniti QX60 Review and Test Drive – Capital One Auto Navigator
- VC-Turbo Engine Technology – INFINITI USA
- 全新2.0T动力，黑色套加身，新年款QX60发布 – 汽车之家
- Nissan Just Issued a Major Recall for Its Funky Variable-Compression Engine – Motor1.com
- INFINITI Engine Technologies – INFINITI Dubai
- QX60 心 無界限，全新2.0L VC-TURBO動力導入 正式展開預售 – INFINITI Taiwan
- 性能、安全 全盤掌握─Infiniti QX50測試篇 – U-CAR
- 全新2.0T动力加持！新年款QX60发布 – 汽车之家
- Nissan Drivers Sue Over Turbo Engines That Suddenly Die Despite Fix – Carscoops
- VC-Turbo Engineering Explanation – LinkedIn
