Blown diffusers: what are they?

If you’ve been following F1 this season you’ll have heard a lot recently about ‘blown diffusers’ – all the rage at the sharp end of the grid. Force India will be testing its own version of the blown diffuser in Hungary this weekend, but what exactly is it?

Put in basic terms, it is a simple way of using the exhaust gases generated from the engine to work with the diffuser, which sits at the back of the car at the end of the floor.

If a neat solution is found, the use of the exhaust greatly increases the efficiency of the rear under-body aerodynamics. The diffuser is directly ‘blown’ by the exhaust gases, accelerating the airflow passing through it and improving the extraction of air from underneath the car. This also increases the overall quantity of air feeding the diffuser and sucks the car to the track at high speeds.

So – if your blown diffuser works – it will create less disturbance to the rear wheels and interact with the low pressure air at the back of the diffuser to create more rear downforce. Both areas should improve the stability of the car and, hopefully, improve driver confidence into corners.

Ironically, blown diffusers are not new technology in F1. Renault developed a similar solution in the early 1980s, Williams also employed one in mid 1980s and they were common from 1985 onwards.