Tech Focus | Shark and Kube. The first KG airboxes for the 60 Mini

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SHARK AND KUBE. THE FIRST KG AIRBOXES FOR THE 60 MINI

Max Bernardi

12 February 2020

In the year that saw the first CIK-FIA approval for mini class materials, KG presented the Shark and Kube airboxes. A totally new project for the Italian company that is a market leader in the manufacturing of moulded plastic accessories for karts

2020 is the year of the first CIK-FIA approval for MINI class chassis, engines and accessories. Their approval, up to now, was delegated to the national Federations. Air filters are essential accessories. This is a field in which KG is unquestionably among the leaders, supplying the major kart manufacturers. The Italian company has approved two new airbox models for MINI: Shark and Kube. Two small concentrates of technology resulting from in-depth studies, computerised analyses, simulations and tests. Let's find out about their characteristics.

DESIGN

For KG, the airbox for the 60 cc engine is an absolute novelty, in fact, in the past the regulations only allowed the manufacturers of this size engine to also approve the air filter. The design therefore started from the most classic "blank sheet", on which, first of all, we tried to establish the priorities of the project. One above all: the search for the right dynamic pressure. To get to the final models, several changes were made using CAD programs and, subsequently, with CFD (Computational Fluid Dynamics) studies, which use numerical analysis to analyse fluid dynamics problems.

PROTOTYPES

Once the shape of the Airbox was defined, the first prototypes were made, with tests on the engine test bench and, subsequently, on the track. Further prototypes were made, also based on these results. For example, a first model, in the simulation phase, gave excellent results, but on the track its dynamics was so out of line as to be harmful. This is because the pressure at the Venturi and the sprayer was too high and did not allow stable carburetion.

TWO MODELS

Dynamic pressure was the most difficult parameter to define: this led to the idea of creating the two different versions, resulting in the Kube and Shark airboxes. Unlike the filters for KZ and OK/OKJ, according to the regulations models for MINI do not have the filter cartridge inside. This means that the dynamic pressure of the air does not find anything that slows it down, therefore the shape and angle of the airboxes are fundamental. Higher inlet air pressure can improve engine performance, but excessive pressure risks unbalancing the carburetion parameters settings. The two airboxes made by KG help the tuners optimise the use of the engine according to the desired performance. The shape of the airbox is also important for cooling the engine: the 60 Mini has an air-cooled engine, which needs as much air as possible to lower operating temperatures. Therefore, the airbox must obstruct the flow of air as little as possible, even though it has to be mounted at the height of the cylinder, since the MINI is a piston port aspiration engine.