Create an Internet search for the greatest four-cylinder engines of all time and it will yield millions of results… all saying essentially the same thing. That the top five four-bangers will probably include such internal combustion luminaries as the Honda F20, Alfa Romeo Twin Spark, Saab B234R, Volvo ‘Red Block’ B230FT and Mitsubishi 4G63.
No doubt about it, these are outstanding engines and each has a valid reason for being listed, from its specific output as standard to its bulletproof reliability when tuned. But what you will not be able to do is buy a brand-new car with one of these engines under the bonnet. They are from a bygone age, where strict emissions directives were little more than a twinkling in a legislator’s eye.
Although we are in the stranglehold of Euro 6 compliance and the introduction of Euro 7 is looming, there are still some precociously talented four-cylinder engines in production. And what’s more, the inline four has now become the format of choice for brands down-sizing from much larger capacity powerplants.
So let’s not go shiny-eyed over engines we miss but celebrate what we believe are five of the greatest four-cylinder engines of today.
When the M139 arrived in 2019 it was lauded as the world’s most powerful production four-cylinder engine, offering up to 421PS from its 2.0-litre displacement. That’s more than 100bhp per cylinder! Built entirely by hand using technologies pioneered in Formula 1, the M139 was developed by AMG engineers to deliver the punch of forced induction allied to the responsiveness and high-rev ability of a performance engine. In contrast to its less powerful siblings, the orientation of the M139 is reversed to optimise airflow into and out of the engine, and it uses a twin-scroll turbocharger and two-stage fuel injection system to deliver the sort of linearity of torque normally experienced in a naturally aspirated engine.
Found in: Mercedes-AMG A-Class, Mercedes-AMG CLA, Mercedes-AMG GLA
Now in its fourth generation of efficient Germanic improvement, the Volkswagen Group’s legendary EA888 can be found at the heart of the latest Golf GTI and related models such as the Audi S3, TT and VW Tiguan R. Available in various states of tune up to 320PS, this direct injection powerplant uses variable valve timing with double camshaft control and two-stage valve lift on the exhaust side to create a careful balance between power and economy. But it is also characterised by innovative solutions for individual details, such as integrating both the exhaust manifold and water-cooled exhaust gas routing to the turbocharger into the cylinder head.
Found in: VW Golf GTI, VW Golf GTI Clubsport, VW Golf R, VW Tiguan R, Audi S3, Audi TT
Ford 2.3 EcoBoost
The largest four-cylinder unit in the EcoBoost family is probably the most adaptable of them all, being featured in front-wheel drive, rear-wheel drive and all-wheel drive models. EcoBoost engines combine three technologies – turbocharging, direct fuel injection and twin independent variable camshaft timing – for power and efficiency. Yet it is probably the high-spec twin-scroll turbocharger with electronic wastegate actuation that has made this engine such a tuner favourite. Among its features is an anti-lag system that keeps the throttle open during gearshifts in order to keep the turbocharger’s compressor wheel spinning so that boost pressure is not lost.
Found in: Ford Focus ST, Ford Mustang, Ford Ranger
Porsche received a lot of negative press for ditching the iconic naturally aspirated flat six from its latest generation of Boxster/Cayman models. But while the new turbocharged flat four motors were not the last word in aural gratification (nothing that improved breathing cannot rectify), they resurrected a classic configuration that won Porsche legendary races such as the Targa Florio and Le Mans. On its launch, the top-spec 350PS version was unique in offering variable turbine geometry, while both 2.0- and 2.5-litre variations feature a novel twin water-cooling setup. This consists of a conventional high-temperature circuit for the engine and an indirect, low-temperature circuit to ensure that charged air arrives in the combustion chamber at the perfect temperature for optimum power.
Found in: Porsche 718 Boxster S, Porsche 718 Cayman S
Inspired by the 900bhp turbocharged 1.5-litre engines used in Formula 1 back in the 1980s, Volvo’s modular Drive-E range was prototyped in world touring cars back in 2011. It aims to prove that the power you can extract from an engine has nothing to do with its size; it’s about the amount of air that you can get to flow through it. Which is why the highest specification versions adopt a supercharger to fill in bottom-end torque and a turbocharger that kicks in when the airflow builds up. And because the compact Drive-E line was engineered for electrification from the start, some models feature a third advantage – a 65kW electric motor. All of this means that even a full-size SUV like the Volvo XC90 can balance epic performance with zero-emission urban mobility.
Found in: Volvo S60/V60, Volvo S90/V90, Volvo XC60, Volvo XC90
Using a similar 500cc per cylinder configuration to Volvo (see above), the four-cylinder BMW B48 is another highly adaptable motor seen in everything from MINI hatchbacks and BMW saloons to the Toyota GR Supra. The K20C1 found in the Honda Civic Type-R and the G4KH installed in the Hyundai i30N are some of the finest hot hatch powerplants in the business, while Mazda deserves some respect for going it alone with natural aspiration and sky-high compression ratios to extract power and torque from its Skyactiv-G engines.
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