one of the posts below is talking about Scangage... I am aware that you can program hex codes into the new SGII to read out horsepower. Obviously, the SGII is reading certain PIM's from the OBDII port and doing a calculation.

I can datalog with my Xcal II and probably can log whatever PIMS are needed to compute "road horsepower". Does anyone know what data is needed and what the equation is to get HP from things like RPM, timing etc. that can be picked up from the OBDII from a datalog?