haiz, the common misconceptions of the laymen. it is not true
that u need speeds in excess of 120 km/h to generate any form of
downforce. downforce or drag is calculated as:
Fdrag= 1/2(density of air)*(velocity of
object)square*(cross reference area)*(coefficient of
friction)
while velocity plays a significant part in increasing downforce,
increasing ANY of the variables in play will give u more drag at
any given speed. for example, by increasing the angle of attack of
ur spoiler (assuming u have an adjustable GT wing of sorts), u
effectively increase the cross reference area (area perpendicular
to the direction of travel) and therefore, one is able to create
the same amount of down force at a lower speed.
that is to say, if u have a spoiler which is effectively shaped to
have a low coefficient of drag AND has a low cross reference area,
u'd generate neglible drag even at high speeds and get around the
same mileage without a spoiler.
hence, defeating the purpose of having a spoiler altogether
