some calculations

["R. Wiratorn [Thailand]" <withu@loxinfo.co.th>]

        hello,there is a formular to calculate top speed of car in EC mag.
                
                I 'd like to know how fast the 280 HP S4 can go.,but I don't
know two
        variables. 1. the frontal area of Audi S4 (in sq.ft.)
                           2. Cd. of Audi S4  (is it 0.29-0.30 ?)
        Do you know ?
                
                                This formular doesn't use vehicle
weight,gear ratio,max rev. 
        to calculate. it use max power,Cd.,frontal area .

                                Power(hp)=8.702E-06*Cd*Area * V * V * V
;V =mph

                                                                            
            thanks