In Super GT’s GT300 category there are three types of car, European style cars built to the FIA GT3 regulations, JAFGT300 cars which are exceptionally heavily modified production cars and a final sub grouping of cars, ‘Mother Chassis’ which have no production parts in their construction at all. This article tells the story of the Mother Chassis and the ‘MC’ cars which resulted from its introduction.

Part 1: The birth of the Mother.

In late 2011 a group of key players in the Japanese motorsport industry headed by Dome founder Minoru Hayashi created a new kind of GT racing car. In Japan there had been a trend toward small teams importing and running European GT cars and Hayashi and the group felt that the local level of engineering talent was falling, and that the decline in engineering ability would be felt across Asia where the motorsport scene s growing rapidly. “Be aware in order to have any racing in South East Asia where there are no sports cars being produced the only option is to import European cars, which was the same destructive path Japan followed” Hayashi wrote at the time. “My suggestion is a policy of – if you don’t have one, make one. The new mother chassis is the basis of that, you can buy just the chassis or a complete car design and build an original car around that chassis. This will allow the focus of racing to be on technological competition and not all about drivers.”



The overall concept was that Hayashi’s company Dome, would create a single versatile chassis using its resources and make it available to any constructor who wanted to use it as a basis of a new model for road or race use. This would allow small tuners who did not have the ability to develop a modern bespoke composite chassis to readily access one.

The chassis designed by Dome would be designed specifically to be able to be utilised in either a FR layout car or a MR layout car.



There were two variants of the chassis envisaged originally one in carbon fibre (above) and one a tubular metal structure (thought to be from extruded aluminium) which would be a lower cost option (below). Both chassis would be dimensionally identical.



The chassis would only form part of a kit of parts which could be bought alongside the mother chassis itself. The kit would include everything that would be needed to build the chassis up into a running car, everything that is except for the bodywork. That would be the responsibility of the customer.



Both composite (above) and metal (below) versions could be mounted with a roll cage and cooling system available off the shelf along with uprights, suspension parts front and rear impact structures and even the composite seat.



Designs for a front engine and mid engined versions were worked up by Dome engineers along with more developed roll structures in order to make the design suitable for using in the Thai Supercar Championship and in GT300. A Hewland sequential transmission was designed to be part of the package also.



The concept proved not only intriguing for but also popular with some of the more technically minded small Japanese tuners and racing teams. Additionally GTA the promoters of Super GT announced that mother chassis cars would be permitted to race in GT300.

Page 2 – The Early MC concepts

