Quote:
Originally Posted by icingdeath88
Ok Harvey, how would one go about correcting for this? I am planning on running a megasquirt. How would you go about figuring what the dwell time should be set to for this setup?
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If you are going to use Megasquirt, there is a great resource in the forums that are there. Some one will have done it before.
The ignition process is, the ECU turns on the Ignitor, which turns the coil on, the coil's magnetic field rises, when the current gets to about 4amps, the Ignitor holds it by dissipating the excess current. The ECU then turns off the Ignitor and the coil, to produce the spark.
But if I was doing it, I would use a scope to look at the signal from the ECU to the Ignitor. Measure the time from the turn on to the turn off. Then look at the coil primary, and measure the time from turn on till the Ignitor clamps the current. This is the “Rise Time” that the coil primary takes to reach saturation. You will see the current rising, then leveling off to stay the same, as the Ignitor holds the current by dissipating the excess.
Fit the new coil, and measure its “Rise Time”, if this is faster than the original coil. Subtract the extra time from the total turn on time, for the ECU.
Eg. Original coil ECU time, 10ms. Rise time 8ms.
New coil rise time 6ms. So ECU on/off time reduced from 10ms to 8ms.
Quote:
Originally Posted by smc
Seems like you would simply retard your timing a little depending on your tuning. o.O
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That will only change the advance time, it won’t stop the Ignitor from dissipating the excess current for a longer time. The dwell time has to be changed.
Harvey.