Their new package encourages the downwash effect from the top of the sidepod to stay attached with the exhaust helping to flow the air downward (Coanda Effect) whilst also keeping the flow from around the side of the sidepod attached for longer. Previously their airflow convergence was hampered by the use of a Tunnel feeding the sideways flow inbound through the false floor. (Picture below). Further to this Red Bull have added the same cooling / vortex generators on the top edge of the sidedpod that are found on the MP4-27. Along with reshaping the engine cover to push the airflow into the path of the downwash and sidepod flow generated by the use of the Coanda Effect. All of this leads to more airflow over the rear floor which in turn generates more rear downforce.
Lastly here is a very basic picture of how the flow is is being directed around and over the sidepods (Yellow Markings), the circled area is the cooling slots that have been added and will also slow down the flow at the top end of the sidepod leading to the engine cover promoting better flow into the downwash area.
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