Suspension development is a continuous process. Once EJ11 started running, the gearbox people began thinking about EJ12. As the rear suspension mounts to the gearbox casing, Haga works closely with those involved in this are. "We look at what areas can be improved from the previous car," continues Haga. "Packaging is also very important, because the rear suspension is all around the bodywork, but we have to have nice airflow, even inside the bodywork as it gets progressively narrower and closer to the car internals.  Suspension bits and pieces are normally inside the bodywork, so sometimes I have to move my parts and the gearbox team has to make alterations to find room for suspension components."

Haga liaises closely with the R&D department at Penske, the company which supplies the dampers and is constantly working to improve performance while making the actual components smaller and lighter. At the design stage, Haga produces what can be called a "standard" rear suspension, but there are several options, in terms of different geometries, built into the basic concept. Once the first parts are built, they are tested using two methods: static testing with all the parts fixed to the gearbox main case and the upright, in order to check stiffness under load. "Last year we also started using dynamic testing, where the suspension is put on a rig which simulates the movement and loads it would be under on the track," says Haga. "It is really useful to be able to simulate suspension performance before the car is actually built."