When Infiniti, Nissan’s luxury division, unveiled the latest generation of its QX50 SUV (2018-2025), it proudly introduced an engine featuring a new technology called VC-Turbo, a turbocharged powertrain offering variable compression. It was touted as revolutionary, and in many ways, it was.
Nissan spent 20 years developing VC-Turbo technology.
Reliability issues have tarnished this technology’s reputation.
Nissan will likely focus more on its e-Power approach in the future.
From an engineering standpoint, this represented the ultimate achievement: an engine capable of changing its compression ratio on the fly. Manufacturers must always find the perfect compromise between a ratio that maximizes performance and one that favors fuel economy.
Nissan achieved this feat, but not without considerable effort. It required twenty years of research and development to bring this project to fruition.
How It Works
In a conventional engine, there’s a direct link (the connecting rod) between the pistons and the crankshaft. The movement of the crankshaft, which rotates and moves the piston up and down in the cylinder, fixes the compression ratio in the combustion chamber. The VC-Turbo engine’s design introduces a multi-link system to replace the connecting rod. A small electric motor activates an arm that adjusts the link’s angle, altering the piston’s stroke within the cylinder. Consequently, compression varies between 8:1 and 14:1 depending on the pressure applied to the accelerator.
When flooring it, the ratio drops to 8:1 to maximize power. During everyday driving, it rises to 14:1 to optimize fuel economy.
It’s seamless behind the wheel.
The Upside
This approach aims to offer the best of both worlds: maximum power when desired, and maximum fuel efficiency the rest of the time. Four-cylinder fuel economy with V6 power; that’s what Nissan promised at launch.
The Downside
Since this engine is more complex, it’s more prone to problems due to the added multi-link system that enables variable compression. Consequently, issues arose. In 2023, the NHTSA (National Highway Traffic Safety Administration), the U.S. equivalent of Transport Canada, opened an investigation into bearing and link failures that caused engine damage and breakdowns. Nearly 1,900 incidents were documented, along with a dozen accidents or fires related to these problems.
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In June 2025, Nissan recalled just over 480,000 vehicles, including 37,000 in Canada, to replace defective engines. A few weeks later, the NHTSA closed its investigation once Nissan took responsibility for addressing the issues. Moreover, the company extended the engine warranty to 10 years and 200,000 km.
Another disappointment has been that real-world fuel consumption remained higher than promised. It’s likely due to excessive hard acceleration by drivers. For maximum efficiency, the vehicle must be driven gently.
Currently, the 2.0-liter four-cylinder VC-Turbo engine powers the Nissan Murano and Infiniti QX60. The 1.5-liter turbocharged three-cylinder version of this technology equips the Rogue SUV, Nissan’s most popular vehicle.
What’s Next?
For now, the VC-Turbo engine remains part of Nissan’s equation. Still, it will be interesting to see whether the company’s e-Power technology eventually takes over, as e-Power relies on hybrid technology and promises a 15% reduction in fuel consumption.
One thing is sure: Nissan pioneered the VC-Turbo approach, which remains a fascinating concept. Could it be improved? Indeed, but the system’s complexity dampens enthusiasm. Adding e-Power hybrid technology, for example, would multiply the risks.
Moreover, variable compression’s role is to deliver power at certain times while maximizing fuel economy the rest of the time. However, the electric motor (e-Power) provides the necessary boost at the right moment, allowing the gasoline engine to remain tuned for economy.
That’s why VC-Turbo will more likely prove temporary. Time will tell, however.
