Nissan’s 1.5L, 400-HP 3-Cylinder Engine Deserved to Live on Beyond Racing
A 1.5-liter, 400-horsepower engine that weighs just 88 pounds? It sounds like something straight out of a sci-fi novel, yet Nissan brought this powerhouse to life for the DeltaWing project at the 24 Hours of Le Mans. This pint-sized engine, nicknamed "Diglett," could rival the power-to-weight ratio of some Formula 1 engines—a feat nearly unheard of for a three-cylinder. With such a compact build, it’s small enough to fit in an airplane’s overhead bin. And yet, it never made it to mainstream production.
We're looking deeper to find what makes this 1.5L engine soo unique and why it deserved a life beyond the track. From engineering breakthroughs to untapped potential, here’s everything you need to know about one of Nissan's most ambitious engines.
Nissan's Bold Entry at Le Mans
The DeltaWing project wasn’t your typical race car entry. This experimental single-seater, which debuted under the Garage 56 banner, looked like something between a fighter jet and a futuristic land racer. Its mission? Showcase innovation. Nissan brought a custom, branded four-cylinder engine to the track in 2012, but that wasn’t the end of the story. Over the next few years, Nissan optimized that powertrain until they’d created something even more radical: a 400-horsepower, 1.5L, three-cylinder engine that could perform on par with some of the best engines in motorsport.
And it weighed just 88 pounds. For context, that’s around the weight of a typical 125cc Vespa engine, yet it packed 10 times the displacement.
Engineering Feats that Made It Possible
Creating such a compact powerhouse took serious engineering innovation. The team at RML Group, a UK-based motorsport and engineering firm, pulled off several feats to make this engine a reality. Their goal was clear: build an ultra-light, high-performance engine that pushed boundaries.
Here's how they did it:
- Material Choices: The valve cover was crafted from carbon fiber, drastically reducing weight without compromising strength.
- Downsized Components: The pulleys and other moving parts were smaller than those found in traditional engines, adding to the engine's efficiency.
- Integrated Design: Perhaps the most unique aspect of this engine was the decision to cast the cylinder head and block as a single unit. This eliminated the need for a head gasket, reducing complexity and the potential for leaks—a common problem in high-performance applications.
For a prototype, Nissan’s engineers were free from the constraints of mass production. They could take risks, and they did. The result was an engine with a better power-to-weight ratio than many contemporary Formula 1 engines.
The Untapped Potential of Diglett
Unfortunately, Diglett never made it to mainstream production. Nissan’s current three-cylinder lineup doesn’t come close to the power-packed performance of the DeltaWing’s engine. The 1.0L turbocharged triple in the Juke, for example, only manages 114 horsepower—a far cry from the 400 horsepower delivered by Diglett.
So, why wasn’t this engine adapted for the road?
For one, it was designed solely for racing. To adapt it for everyday use, Nissan would have needed to meet road-car regulations, which often add weight and reduce output. Additionally, the one-piece cylinder block and head design, while ideal for racing, poses maintenance challenges for street use, where serviceability and durability are priorities.
Alternatives for Power-Dense Three-Cylinders
While Diglett remains a unique engineering marvel, it isn’t the only power-dense three-cylinder on the market. Today, enthusiasts can look to Toyota’s 1.6L turbocharged triple, which powers models like the GR Corolla and GR Yaris. With 300 horsepower and 295 lb-ft of torque, Toyota’s engine offers impressive power in a compact package that’s more readily available than Nissan’s prototype.
Conclusion: A Visionary Engine That Deserved More
Nissan’s 1.5L, 400-horsepower three-cylinder engine was an impressive feat of engineering and a testament to what’s possible when rules are pushed to the limit. It’s a reminder that, in motorsport, engineering creativity can achieve astonishing things—even if they don’t always make it to the road.
Who knows? Maybe one day, we’ll see similar engines on the road, harnessing the lessons learned from the DeltaWing project to power a new generation of lightweight, high-performance cars.
