From 3 to 2 Cylinders: The Engine Debate

From 3 to 2 Cylinders: Cars Lose Cylinders

Three-cylinder engines are becoming obsolete. The next step is the two-cylinder engine: future powertrains will have only two cylinders, according to the thesis opening this discussion, referencing a video and a specific timestamp at 10:12. The logic is hybridization: the combustion engine acts as a generator, and its shortcomings are covered by the electric motor. This is not a laboratory futurism. The thread mentions the Ford 1.0 EcoBoost micro-hybrid version and the BMW motorcycle two-cylinder used in its i3 as a range extender. The direction is set; the question is whether it is advisable.

The Physical Problem of the Three-Cylinder Engine

The first drawback is mechanical, summarized by one participant: a four-stroke engine (intake, compression, power, exhaust) with three cylinders passes through an instant where none are in the power stroke, causing vibrations. With four cylinders, one is always pushing. The solution, according to this explanation, involves additional counterweights and balance shafts, patches that work. Some recall that BMW K75 or Triumph three-cylinder engines run fine. The most repeated counterargument: what matters is not just the number, but specific power. A 120 hp three-cylinder does not behave like a 70 hp one.

Real Consumption vs. Certified Figures

The second front is cost. Small engines shine in lab cycles, but less so on the road. Specific cases: a BMW i3 REX traveling from Barcelona to Madrid with obligatory stops and consumption described as pathetic; a 7.5 liters per 100 km at 120 km/h versus the 6.5 L/100 of a Toyota Corolla 1.6 110 hp that cost 2,000 euros. According to another participant, the Fiat 500 Twinair promised more power than the old Fire 1.2 and ended up consuming more when pushed. Forcing a small engine has a price.

Economic Reason and Regulatory Push

Behind downsizing is not just physics. It is argued that Brussels has set emission limits below what technology allowed, and the response has been to reduce displacement and increase turbocharging. The fiscal consequence is visible: according to the thread, a 1.0 three-cylinder falls below 8 fiscal horsepower, and the municipal circulation sticker is cheap. The other side: a three-cylinder, 75 hp Ford Fiesta atmospheric model was around 17,000 euros. Less engine, same or higher price.

The Exception That Confirms the Rule

Against downsizing, there is a chorus defending larger displacements. The 1.5 to 2-liter four-cylinders —Renault’s 1.3 TCe, Honda and Mazda’s Japanese engines, Toyota’s 1.8— are cited as references for consumption, performance, and reliability. The Mazda 3 atmospheric 2-liter four-cylinder appears as a standard-bearer. And at the other extreme, the V6: a Mazda Xedos V6 that made an officer doubt at a night stop whether the engine was running. The driver insists that sound and vibrations in a six-cylinder are zero.

Maintenance and Longevity: Where the Argument Breaks

Here the narrative cracks another way. 247,000 km are documented on a 2006 Toyota diesel without a breakdown and 117,000 km on a 2006 VAG gasoline engine with indirect injection. The key many point out: care the turbo. Let it warm up before demanding and two minutes idling before turning off after a highway drive. As one participant notes, direct injection engines accumulate carbon because gasoline does not clean the valves. A problem that does not depend on the number of cylinders.

Nostalgia as an Argument

There is a part of the analysis that is mourning what is lost. Coupes like the Puma, Tigra, Calibra, Celica, Corrado, or Eclipse have disappeared from ranges. Today, the same platform serves multiple models with different badges. At the emotional extreme, a V8 as God commands and phrases referring to a way of understanding cars that almost no one manufactures anymore. The gap between certified cycle and real use is not closed by an extra cylinder.

What May Happen

The prediction, with reservations: if hybridization advances and the combustion engine is relegated to a generator, the two-cylinder makes sense in urban city cars. On open roads, with 1,500 kg weights and 19-inch wheels, physics takes its toll on consumption and brakes. Another matter is reliability: for one participant, any modern engine should last 150,000 km without coughing, and it remains to be seen who delivers.