LaFerrari, 458 speciale diffuser flaps imperfect sealing

[g-force_addict]

What's the aerodynamic effect of imperfect sealing of the moving diffuser flaps in LaFerrari and the 458 Speciale?

http://458speciale.ferrari.com/en/#innovations

If such flaps were placed in a venturi tunnel to reduce diffuser angle thus drag and downforce
Would its sealing be more critical?
Or maybe sealing in the venturi tunnels is not that important as the lower pressure zone is usually in front of the tunnels so the main concern is smooth airflow?

[PNSD]

One thing you have to remember is that adverse effects downstream will be felt upstream.

This is in reply to your last sentence.

As for the main question, what do you mean by the sealing? As in between the strakes or? I'm a little lost.

[rjsa]

Vortices for sure. Extra drag and less DF when compared to a properly sealed assembly.

[g-force_addict]

One thing you have to remember is that adverse effects downstream will be felt upstream.

This is in reply to your last sentence.

As for the main question, what do you mean by the sealing? As in between the strakes or? I'm a little lost.

By sealing I mean that air can't leak thru the flap edges to the fixed venturi tunnel sidewalls or ceiling.

[theWPTformula]

I think I understand what you're trying to say...

The imperfect seal between the upward slope of the diffuser and the leading edge of the moveable flap (when the flaps are in the downward position) will just have a slight increase in drag compared to a perfect seal ie if the leading edge of the flap was flush to the floor/diffuser surface.

No extra downforce, just a bit more drag. I think I've answered your question!