Do you think that the sunroof gives any measurable downforce when tilted? It seems that it would as it is a larger surface that the rear tail that comes up at 75mph.

 

Funny. I have been wondering the same for some time now, but was afraid to ask :-)

 

I really don't know about downforce effects of the roof itself. But when a 991 has Sport PASM, the rear spoiler goes up at a steeper angle when the sunroof is up to compensate for the a different airflow over the roof. The effect is to move air separation back and reduce drag as well as increase downforce.

 

Actually, I am quite sure that the rear spoiler in my non SPASM goes up a bit more when the roof was tilted open. Did not try while the roof is slid back, too much wind noise for my liking at that speed.

 

The rear spoiler goes up at a steeper angle when the sunroof is open (not sure about tilt) on all 991s.

 

From the Configurator:

"PASM Sport Suspension

Electronically controlled damper system with two manually selectable settings (standard and sport). Includes a reduced ride height of 0.39 inches (10 mm) from the standard Carrera S suspension.

Also includes an aerodynamically adapted front spoiler lip and further extension of the automatically deploying rear spoiler for futher lift reduction."

I have noticed that I can see it go up more from the drivers seat when opening the sunroof. I thought it was the angle, but the Configurator describes it as "further extension".