Why Ferrari reverted to their original diffuser spec in Imola after Portimao experiments

Anyone keeping a close eye on the Ferrari SF1000 at Portimao would have spotted several different rear diffuser specifications running on the car, while the team reverted to their standard-spec elements for the races in Portugal and at Imola. In this week's Tech Tuesday, Mark Hughes investigates what they are up to, with technical illustrations from Giorgio Piola.

After their recent spate of aerodynamic developments, Ferrari arrived at Imola with the same combination of elements they raced in Portimao after a series of experiments during practice at the Algarve track.

That combination comprised the barge board, nose cape and forward turning vanes introduced at the Nurburgring, together with the outer floor introduced and raced in Portugal featuring the three small diagonal flaps ahead of the rear tyre in place of the previous 2020 arrangement of a single, bigger one-piece raised flap (see the illustration further down in this piece). These were combined with the car’s original diffuser, rather than the modified one which was trialled (but not raced) in Portimao.

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Ferrari have consistently maintained that some of the new parts are aimed very much at next year’s car and the inference from the sequence of different diffusers used is that the one trialled but not raced in Portimao was created just to give a direct comparison with the 2021 version, which differed only in the longer fences permitted this year. In this way the exact downforce loss of the shorter ’21 fences could be measured.

But that 2020-spec version of the ’21 diffuser is not intended as a race item for this year’s car. Hence the reversion to the standard diffuser in the Portugal race and throughout the Imola weekend, as shown in the image below.

The airflow around the diffuser will be quite different next year, given the narrower floor and banishment of floor slots. Hence, the different design.

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The standard 2020 diffuser features angled slots at the bottom of its outer wall and the alignment and arrangement of the fences is quite different.

By contrast the outer floor, barge board and cape are very much part of the SF1000’s development and have contributed to the car’s improved form of late.

There was also a revision to the rear wing for the different downforce and efficiency demands of Imola, with a more neutral main plane but a more aggressive upper flap angle.

This would give greater downforce but a more than proportional increase in drag – though evidently still gave a better lap time around the Imola layout. This would all have been confirmed in simulation before the weekend.

The Ferrari aero and production departments have clearly been flat-out over the last few weeks despite the flurry of races, as they continue to try to haul the team back towards the front of the grid.