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TKART magazine Tech Focus | S1087 by D.M.A. Racing Gears, the seamless gearbox for shifter karts
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Giacomo Mantovani
24 July 2023 • 20 min. read
Changing gears without having to lift your foot from the accelerator: utopia? No, a reality. That, according to the manufacturer who patented it and the tuner, Machac Motors, who participated in the project, allows a gain in terms of lap time ranging from 2 to 5 tenths ... Although it is still mainly top secret, we have analysed it and we will tell you about it
It is certainly not news that "exchanges" in technology can take place between the various classes of motorsport: solutions adopted and consolidated, for example, for motorcycles can be adapted within about a decade and turn into potential revolutions in areas, apparently, light years away ... Like karts! What are we talking about? Of the protagonist of this article, the seamless gearbox for kart engines developed thanks to the partnership between two companies in the Czech Republic: Machac Motors, a team of kart engine tuners, and D.M.A. Racing Gears, a company specialised in transmissions for racing engines. Defining this revolutionary project is not at all a gamble, since seamless technology, or a gearbox without interruption or, rather, without torque variations, promises to radically change the approach to driving a Shifter kart, allowing drivers to change gears without being forced to lift their foot from the accelerator. In fact, this type of gearbox allows for a smooth and uninterrupted transition between one gear and the next, ensuring greater efficiency and better performance on the track, thus eliminating the traditional interval of time necessary for changing gears and allowing drivers to maintain maximum acceleration and grip when cornering and braking. The consequence of all this? Faster lap times and an easier driving experience. We went to the Machac Motors headquarters to find out more about this project, to understand what elements it is composed of and what process was followed for its design and production. In this sense, a small premise is necessary: although the seamless gearbox is a technology that is now well known, each manufacturer designs its own system with precise mechanical characteristics and therefore with its own technical specifications, even if they are all functionally similar. To confirm this, the seamless gearbox unit by D.M.A. Racing Gears has been subjected to a patent: a process not yet finalised, which is why we were not allowed to photograph some components, which are still "top secret"”.

Seamless technology was applied for the first time in the 2000s by some car manufacturers for the automatic gearboxes of some production cars: for example, we mention the Volkswagen DSG (Direct Shift Gearbox) dual-clutch gearbox launched in 2000. However, the first application in motorsport dates back to 2008 in MotoGP when it was introduced by HRC (Honda's sports division): since then, seamless technology has become an essential component of the premier class of motorcycling. As far as the automotive scene is concerned, however, seamless technology was initially adopted in Formula 1, then implemented with electronics, to later spread to other classes, such as rallies and GT competitions. The illustration shows the difference between a traditional gearbox group and a seamless one.
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