Two of a kind

Columns: On the technical side
An evergreen 'technical' diatribe, the one between 2-stroke and 4-stroke, returns to the fore when it comes to promotion and re-launching.

The stage of motorsport competitions, not least Karting, has always been a flywheel of ideas and technological developments and the technical distinction between 4-stroke and 2-stroke internal combustion engines has, over the years, given fuel for thought that revive the importance of not leaving anyone behind and to continue developing both constructive philosophies to achieve overall improvement.


Since the internal combustion engine has existed, both as a thermal machine aimed at locomotion and beyond, it has been a succession of evolutions that have led the latter to be one of the key agents of modern evolution. From the initial idea that was of the Italian pioneers, Father Barsanti and Engineer Matteucci, it moved first to the improvement of the 4-stroke cycle by Nikolaus Otto and then a few years later to the development of what is the 2-stroke engine by Engineer Dugald Clerk.

Although the theoretical aspects at the foundations of the 2-stroke and 4-stroke engines are different, over the last few years both types of construction have been implemented to achieve a "technical-political" balance deriving from the need to reduce waste and at the same time to re-invigorate a movement that, due to the economic crisis and, more recently the pandemic, is suffering chronically from an impoverishment of new developments.

From the literature and technical experience, we know that the 2-stroke engine is less "complex" than the 4-stroke engine mainly due to the absence of many components such as valves, shafts and chains related to the distribution. A two-stroke engine completes the cycle in two piston strokes and this means that a cycle is completed with a single rotation of the crankshaft; therefore the compression and expansion phases take place in the two strokes, while the replacement of the charge (also called washing) takes place with the piston near the bottom dead center, thanks to the washing pump. In theory, the 2-stroke engine, in addition to having greater power with the same displacement compared to the 4-stroke, could also be cheaper from the point of view of consumption if there were no exhaust leaks. These and other technological limitations are responsible for a large part of the polluting burden that make traditional 2-stroke engines largely problematic compared to the limits imposed by the latest regulations on the subject. In the name of this "convergence" between economic, environmental, and technical needs, we can take a step forward from the point of view of communication and certainly clear the workbench of the concepts of "complex Vs simple" when we talk about 2-stroke Vs 4-stroke and arrive at a much more relative view of the issue, which leads to appreciate the benefits of both without dwelling too much on the goodness of one or the other choice.

Obviously, this transversal rotation between the two architectures leads to an increase in costs due to the development of the same, for example, in the increasingly massive use of materials with characteristics such as to allow a reduction in weight for the 4-stroke or of materials capable of increasing the longevity of the 2-stroke without damaging its DNA too much. It is astounding to ascertain how the vast majority of people who approach karting by trying a kart with either, or indeed, any engine are thrilled, enthusiastic; the epoch of ours when we interviewed the two great technicians of the two architectures, Thiel for the 2-stroke and Forghieri the 4-stroke, in issue number 270 of Vroom, with all the related disputes between the 2-stroke 'purists' and those who saw in the 4-stroke a business opportunity and little more, seem ages ago.

Full awareness of the current moment brings the whole word of karting into a new vision, sweeping the clouds of preconceptions and pessimism at all costs, and it ought to – and we do - promote Karting in every which way and as much as possible in all its architectures, from full electric to 2-stroke to 4-stroke, in order to bring as many people as possible to the stage, that is, the track: children, teens, adults who discover for the first time, or rediscover the essence of our beloved sport without spending a fortune, because - lest we forget – Karting is, first and foremost, fun and passion.

Created by: scorradengo - 30/01/22

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