Originally posted by FoxEric:
And tuning is done by monitoring the exhaust for rich/lean.
The unit doesn't monitor the exhaust, you go to the dyno and tune with an A/F meter.
But the ignition timing is what separates the GReddy and that's the part that I'm unclear about in terms of timing. What response are you monitoring as you adjust the timing tables?
The timing signal is routed through the eManage microprocessor which calculates the time interval between ignition pulses. The map tells the microprocessor how much advance/retard to add/subtract from the base signal coming in to the eManage. Then it sends out the modified signal.
Is your only feedback the onset of detonation or is there something else that you can monitor to be sure you aren't putting your engine in peril?
The factory pcm will pull timing in the event of detonation, not quickly, but it will do it. You are better off listening for engine ping and looking at the results of a dyno run. You can see the results of the pinging as a spikey region in the torque curve, Just ask PA3Liter.
By the way, what is it that prevents you from reducing the fuel input to lean things out? Thanks.
Eric
What do you mean? You reduce fuel output by shortening the injector duty cycle. This is accomplished with the Airflow adjust map. Essentially, the first thing you do is go to the dyno and baseline the car. Then you look at your AF ratio curve and use the airflow map to lean out areas that are too rich, and enrich those areas that are lean. Try to shoot for a steady 12.5:1 across the board. Then, if there is one area that has a lean spot in it, you use the injector control map to add a few % to the duty cyle JUST in those areas, until you get it straight across the board.
Then you start to increase timing. Slowly at first you can add a few degrees across the rpm range and do a dyno run. Listen/look for pinging. When you get to where you just hear a little pinging, you can do one of two things:
1.) add a little fuel with the injector map at those spots where the pinging is heard. The extra fuel will cool down the combustion temp and probably remove the pinging. However, it may drop torque at that point so it may not be worth it. You will use the 'map-trace' feature to figure that out.
2.) pull timing back off at that point.
Above all make the changes with the torque curve in mind, not adding fuel if it drops your torque numbers.
Then you are done.
I hope that explains the process well enough.
warmonger
