Are the Best Engines in the World Japanese?

I’ll admit it: one day I start being nervous about stepping outside - and, frankly, for good reason. After handing the crown of the world’s best diesel engine to Volkswagen’s legendary PD130, and after arguing - with perfectly solid reasoning, I might add… - that FIAT builds the best engines on the planet, I’m back again with part III: it turns out the best engines in the world are Japanese.

So where does that leave us? I know - apologies. But in an era when electrification dominates every conversation, any excuse is a fair one to spend a little longer talking about internal combustion.

Call me old-fashioned, but the century-old technology that set the world in motion is refusing to die, no matter how many obituaries get written. Even when refineries are shut down overnight and then a war gets blamed for fuel costing more than two euros. Even so, some people will still be more outraged by the title of this column…

Japanese engines and the reputation for reliability

All right then: there are other engines with the same stubborn habit of resilience - the sort that take a beating, keep going, and refuse to vanish. I’m talking, as everyone knows, about Japanese engines.

The reliability reputation of Japanese engines is to Toyota, Lexus, Honda, Suzuki or Mitsubishi what safety is to Volvo; what luxury is to Mercedes; what diesel engines are to Volkswagen; or what oil spots on the driveway are to Land Rover.

Where does that reputation come from? From everywhere - and it echoes all over. It’s the grandfather who owned a Honda Civic that never caused trouble, and the great-uncle who “knows a Toyota Hilux” that covered a million kilometres without an oil change. That’s how urban myths work: “whoever tells a tale always adds a detail”.

Exaggerations aside, the reality is that Japanese engines are genuine contenders for the best engines in the world because they deliver real value. I’m not guessing here. I competed in seven endurance races - including two 24 hours - in a Citroën C1 running a Toyota/Daihatsu engine, without a single issue. Flat-out, the whole time.

The pessimists will say that was then. Maybe - but maybe not. Not long ago, I published here on Automotive Reason the case of a Toyota RAV4 that sat underwater for a long period and then went back to work as if nothing had happened. That doesn’t happen by accident; it happens because of quality. The broader question is: what generally explains so much quality in Japanese engines?

One design, many markets: why Japanese engines are built with margin

You can add whatever arguments you like (for or against), but for me one of the main reasons is that Japanese manufacturers, as a rule, develop the same model for multiple markets. Take the most extreme example: a Toyota Hilux might be shipped to Europe (where both fuel and roads are typically high quality), or it might end up in the Middle East, where roads are what they are - and fuel quality can be too. And what applies to a Toyota Hilux also applies to a Suzuki Swift or a Honda HR-V.

A lot of these cars use over-engineered components - which is another way of saying they’re prepared for the worst. And not just the worst: they’re also built around the best - better turbos, better ancillaries and better hardware overall. It’s no coincidence that some of the finest engines for tuning fans are Japanese.

I won’t tell you to whisper Toyota 2JZ-GTE, Nissan RB26DETT, Mitsubishi 4G63 or Honda K-Series into the ear of that car-obsessed friend of yours - or your mechanic - because that would be odd. But it’s a safe bet they’d get goosebumps. So why did these engines tolerate such dramatic power increases?

The 280 bhp “gentlemen’s agreement” and what it really changed

Here’s where we leave opinion behind and move into fact. By the late 1980s, Japan was dealing with an issue that had nothing to do with engineering and everything to do with politics. Road deaths were rising again, and the Government was starting to view the horsepower arms race among sports cars with growing concern.

The industry moved first. Rather than waiting for legislation they couldn’t control, Japan’s leading carmakers reached an informal understanding: no car sold in Japan could advertise more than 280 bhp. A few years later they took a similar approach with motorcycles that exceeded 300 km/h. My generation remembers exactly the shockwave created by the Suzuki GSX-R 1300 Hayabusa - and yes, I’ve already written an article about it.

This was what the Japanese call jishu-kisei, voluntary self-restraint. A gentlemen’s agreement between Toyota, Nissan, Honda, Mazda, Mitsubishi and Subaru. For roughly 15 years, brochures kept repeating the same magic figure: 280 bhp and a top speed of 180 km/h.

The interesting detail is that the agreement governed what could be printed in catalogues - not what engineers were allowed to build. And Japanese engineers, like any engineer worthy of the title, simply carried on doing their job. They kept creating tough engines, competition-ready, with headroom far beyond what the official numbers suggested.

That’s why the Nissan Skyline GT-R - R32, R33 or R34 - always declared the same 280 bhp. With just one or two modifications, you could uncover at least another 150 bhp that was effectively “hidden” from view.

Motorsport roots: RB26DETT, 4G63, 2JZ-GTE and Honda K-Series

There’s also a technical reason for this apparent mechanical “generosity”: racing. Many of these engines were conceived with competition in mind. The Skyline’s RB26DETT was developed for Group A homologation. The Lancer Evolution’s 4G63 was tied to the WRC.

To comply with the agreement, it was enough to limit what was easiest to limit: more conservative ECU maps, lower turbo boost, or simple restrictors in the intake system. That’s why names like 2JZ-GTE, RB26DETT, 4G63 or Honda K-Series became legendary among people who love engine builds. They aren’t magical engines. They’re engines designed in a period when Japanese engineering worked with margin - a lot of margin.

The agreement eventually faded away in the mid-2000s, when the industry itself acknowledged what everyone already knew: there was no direct relationship between advertised power and road safety. But the legacy remained. For well over a decade, politics capped the numbers and engineers responded with overbuilt, understated and exceptionally durable engines.

Seen this way, perhaps the title of this column isn’t so provocative after all. The best engines in the world could very well be Japanese - not because they’re indestructible (nothing is, except that Toyota Hilux from our great-uncle’s story), but because they were born in a context where engineering had to answer real-world demands. Europeans have done it too. Just take a hop over to North Africa and look at the still-young Peugeot 504 and 505 - the queens of Africa - or see how the legendary Mercedes-Benz 190s are getting on.

I could keep going and talk about Toyota’s hybrid engines, or the 100% electric models that come with a one-million-kilometre warranty (those, I suppose, really can manage it without an oil change), but as I said right at the start, I don’t feel like talking electrification, ok? Still, if you enjoy a good electric-car soap opera, it’s absolutely worth jumping over to that article.