turbof1 wrote:How usefull a DDRS or passive system is? That actually has little to do with the circuit being high or low downforce, but more about how many straights there are and how long they are. In theory, and I say in theory, the concept will always have benefit: you can add additional downforce without a drag penalty. How large the benefit is depends on afore mentioned factors.
On Spa it is reckoned to have alot of advantage, especially Lotus their system since it will also shed drag at eau rouge. if n-smickles numbers are even remotely right it is something you want to have: you can reduce the AoA of the rear wing with it which would shed alot of drag, more then the 6% the VE adds.
The drag of the rear wing is what provides downforce through the corners. Reduce drag at Eau Rouge and other fast corner, and there will be little downforce to keep the car on track. A passive drag reducer on the straights could be a great idea, but how do you prevent it working on high speed corners?