s12 Air drag.
 

Does any one know what is the s12 Cx nad frontal area.
I have a piggy back computer ecumater (polish copy of smt6 but a bit improoved) and it hava a an onborad dyno, besides that it can alter the AFM or MAP output voltage with two corection maps temerature, knock or what ever, lounch control, and it can retard( for now) both ignition signals in a twin spark silvia.

i think its around 0.34. yeah just checked it is 0.34.

there is rolling resistance to consider as well

The roling resistance and and transmition loses can also be imputed. I have print out from my las dyno and it shows haw much HP it looses at certen rmps. It will not be as acurate as a normal dyno du to changable wind and weight of the car but it can show at leest a general number and the graps of the torque and HP.

the smt6 isn't a piggyback system. and aren't you meaning the ecumaster???

Perfect power SMT6 IS a piggyback competer ( i had one instaled in my old car ) and yes i meant ecumaster

Ok i tested the mobile dyno today. If the data i imputed is corect i have 210 hp and 280 Nm.
Sound about right for a ca18et with a T28 at 1 bar of boost.
And the dyno showed knocking problems due to changed ignition by changind the AFM output voltage.