two silly questions:
1: does anyone have a map of the factory ignition advance? im replacing my ecu, and will have to build my ignition map from scratch. could take a while unless i can find a factory one i can copy for a base.
2: does anyone know what the flow rate is on the 919 injectors? or 929? such information would be nice to know for initial fuel settings. i have googled the snot out of them and cant find much good info.
Thanks boys and girls!
I certainly hope you can find a 3D copy of the ignition map. Otherwise you are going to have to work it out yourself: not a simple task! The problem you face with the Megasquirt unit is synchronization of the input from the Crankshaft Position Sensor (CPS) to true TDC of the #1 and #4 pistons, something the CPS does not do. It is a symmetrical 12 pole sensor providing a pulse every 30 degrees of crankshaft revolution. Without an input from the TDC sensor mounted on the cam the ECU does not have the information necessary to sync the ignition pulse to the crankshaft position. Commonly, if there is only a CPS the rotor has either a missing pole or a double pole positioned some 60 degrees BTDC which the ECU "sees", and the next pulse is interpreted as a sync for determination of ignition timing. In this case cylinders 1 and 4 sync to that, while cylinders 2 and 3 sync to 6 pulses after that. The problem you face is working up a map that takes a variety of inputs into consideration: the basic timing determined by RPM modified by (in no particular order) throttle position, the change in throttle position from the previous reading, the rate of change (rolling on the throttle as opposed to snapping it open), MAP sensor input indicating load, coolant temperature, rate of change of engine speed, proximity of RPM to redline, and whether you want a hard or soft rev limit.
There is a way to kludge up a simulator that will give you a way to determine the stock map by generating inputs that emulate the ones on the 919, but it will take some sophisticated electronics and a dual trace storage type oscilloscope in order to obtain the necessary data to write a map. Fortunately there are o'scope packages that can be installed in a standard PC, greatly simplifying the data collection process, but with the amount of data generated it will take some time to interpret it and write a useful base map. One thing's sure: you will be learning volumes!
Undoubtedly Megasquirt can provide the information necessary to accomplish this, but whether they can also provide a map is up for grabs.
As to determining the flow rate of the injectors -- it's pretty simple to do by dismounting one, mount it to flow into an accurately graduated beaker, feeding it fuel at ~40 PSI, activating it for a predetermined period of time and accurately measuring the amount of fuel it flows in that time. Pretty simple compared to everything else you will be doing.
Sounds like a great project! Keep us in the loop.