As is known, with the 2020 homologation for the MINI category, the International FIA Karting Commission aimed at bringing together under a single regulation all the homologations, previously national, dedicated to these classes. The directives are not valid only for chassis and engines, but, as it happens in the higher classes, also for accessories such as brakes, fairings and air filters. Righetti Ridolfi, one of the world’s leading companies in the field of kart accessories, of course was prepared for the new regulations and presented Alien, its first airbox designed for the new international MINI category.
As mentioned, this is the first filter manufactured by Righetti Ridolfi for 60 cc engines. In the past, given the different homologations active for each nation, the investment necessary for the design, production and homologation would not have been supported by adequate numbers. With the implementation of the new CIK-FIA homologation, things have changed, and the Italian company was absolutely ready and employed its remarkable experience gained in the production of the numerous models of filters intended for the higher categories. The design started from a CAD design based on the reference measurements imposed by the regulation. From here, different shapes have been tested to define the best one to guarantee a greater performance of the engine. From the CAD design, the next step was the testing implemented utilizing CFD (Computational Fluid Dynamics) programs, which simulate the air flow and allow to evaluate the airbox shape in depth.
Once the design was complete, to move on to the actual test phase it was necessary to create a prototype of the filter which is done via a 3D printer. Its utilization allows not having to make molds, thus saving both time and investment in case the prototype needs to be modified at a later date. The first phase of the tests takes place at the flow meter, where Righetti Ridolfi invests a lot of time to verify the air flow rate of the filter and the speed at which it reaches the carburetor. The final tests, instead, take place on the track where the filter is assessed in its actual working environment. Track tests are of fundamental importance because during a real lap the kart, alternating between straight and curved sections, continuously changes speed and, consequently, the speed of the air entering the filter with respect to the values tested with the flow meter changes as well. A further variable which can be verified on the track is given by the presence of other karts which, being in the front, can significantly decrease the air flow that the filter receives in the most optimal conditions available. All the data collected during the tests contribute to the best development of the project.
ALIEN, THE FILTER
Moving on to the more specific analysis of the Righetti Ridolfi filter, we can start from its name, Alien. The inspiration comes from its shape which, with the water protection mounted, recalls the head of the famous Alien protagonist of the homonymous movie. Of course, the similarity is the result of chance because, as explained by Giampaolo Righetti, owner of the company with his brother Maurizio, the form of the Alien airbox is the result of a more technical objective: “To provide the most direct air flow possible, in order to have excellent results at low RPM and in the transition from low and high”. But that is not all, because in addition to favor the speed of the carburetor air intake, the airbox design, developing downwards and without forming obstacles in front of the cylinder, aims at offering a better engine cooling. This is an important feature for a category in which cooling takes place through air and is crucial for performance.