Ferrari brought a couple of small updates in Korea all targeting rear downforce. They also tested an older rear wing, used in Belgium, which features only two gills on the endplates. The certain rear wing was also tested in Japan. The reason, is simply because of the nature of the Korean track which has 3 long straights at the beginning and then fast flowing corners for the rest of the lap, so Ferrari tested both a high and a lower downforce setup but at the end they opted for the higher downforce one.
The first small update is a new fin on the front brake ducts (highlighted), aiming to produce a vortex and improve flow towards the rear of the car. This shows the complexity in design of today’s F1 cars, as s small part on the front of the car actually affects the rear.
The other two updates are actually parts raced in previous races which had been replaced with ‘upgrades’. Reverting to the older parts though suggest that they weren’t really upgrades but maybe downgrades. The first of the two are the vortex generators below the wing mirrors introduced earlier this season (1st drawing) but were later modified by attaching the mirror to the one away from the driver in order to reduce the strength of the vortex it produced (2nd drawing). This weekend though they reverted back to the older design (1st drawing). These two vortex generators induce vortices to help direct the exhaust plume down towards the diffuser.
The other update is to the diffuser’s footplate. Again this small tunnel on the footplate (1st drawing) was introduced earlier this season to push the exhaust plume down inside the diffuser to energize the flow, but was then removed as an ‘upgrade’ as Ferrari’s CFD and wind tunnel test deemed it unnecessary (2nd drawing). This weekend again though, they reverted back to using it.
Both of the later two updates are just another confirmation Ferrari has been experiencing wind tunnel problems.