I received an Innovate Wideband lambda/oxygen/AFR gauge for Christmas and decided to get it installed on my ’87 classic Mini today. Last year I fitted a new stainless exhaust system with a stainless Maniflow LCB 3-2-1 exhaust header, stainless centre silencer and RC40 millennium twin centre exit DTM back box. The lambda sensor requires fitting a threaded boss into the exhaust. The exaust system has a Y piece where the headers join to the centre pipe, and this is th most appropriate place for a lambda sensor as it measures all cylinders.
For my Stellaris Launchpad engine simulator, I wished to add a calculation of the Air to Fuel Ratio (AFR) or lambda/equivalence ratio for the current engine conditions. I did this crudely by using the throttle position, engine speed (this->s) and current fuel pulse width (this->F) as factors in calculating the AFR:
this->AFR = (0.32666 * this->s * this->throttle)/(this->F);