Originally posted by dansplace:
Hey tailslide,
From my understanding, the ecu switches over to open-loop at 20% or more TPS.
dan, unlikely to be the case.
the open loop mapping existed as some form of a fixed "safe" mapping, designed to prevent things from going awry under full load. of course, having the benefit of a fully programmeable ecu also enables u to max out the potential of this map for peak power and torque.
at part throttle position, the ecu will continue to read off individual values of the lower load points and continue to make adjustments from the readings it receives. as load, rpm, air temp, intake velocity, tps.... etc all fluctuate too much at low rpm, part throttle, it would do the engine and driver more good when the ecu functions at closed loop to enable the ecu processor some leeway to make adjustments to make driving smoother. under WOT, the increase in these parameters are more steady and predictable (there is less fluction in throttle position since u've decided to floor it) and it is safe to follow the readings given in the open loop programme.
but then, i am stating in general wat ecu's are supposed to do under different load conditions. perhaps there are some which would do otherwise under even low loads such as 20% TPS.
