Is there a way of replacing the flapper AFM and still using the Motronic ECU, or would I need to go for a full programmeable one?
My 1994 engine has a flapper AFM. I was wondering if one of the later hot wire ones would speak the right numbers to the ECU so as to be a plug in substitute, but that seems intuitively optimistic!Weren't the 24V ECUs all hot wire AFM Chris? Mind you, looking at the figures from my 12V RR session, the flapper maybe isn't as restrictive as we thought it might be. It didn't cross my mind until now, but I could have taken one along and fitted it temproaraily to see jsut how much difference it makes. I'll try(!) to remember to do this next time I take the car to the RR. We wouldn't have had the time at the last session anyway, but I can do it next time.
I can say for certain that you cannot use the wrong type of flow meter with a standard ECU that was not meant for it. The newer (and much better) hot-wire types need a different supply and the output signal is not directly compatible with the potentiometer from a flap type. (The hot-wire types do not restrict the air flow like a flap does, but the signal is much harder to interpret.)
The laser-trimmed discrete resistors are still a pot - potentiometer. It doesn't have to be a stepless device to qualify as being a pot. ..and gain, I don't think we are looking to redesign the ECU here, just adapt (if practical) the hot wire AFM to a flap-type ECU. If the hot-wire outputs a PWM signal dependant on flow, then given the transfer characterisitc of both types, I can probably come up with a small and inexpensive box that will allow the use of the hot wire AFM. For it to work, no ECU mods will be involved.I do not know what the montronc is but the L-jet has the map in the AFM
it is not a pot. it has a bunch of LASER trimed resistors that are selected one at a time as the flap moves.
but I have to say reworking and pigybacks systems cost more or as much as a new programable ECU. I would only go that way if you need the OEM for smog inspection or somthing. I guess there is somthing for plug 'n' play if you can not work with wires.