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5.1.10 Mapping -> Ignition
Ignition timing table is default set up with MAP reading at it Y-axis. It’s
possible to change the Y-axis of the ignition timing table by the label:
Mapping -> Ignition -> Flx Ign Angle Base Y
If Throttle based ignition angles are choosed, make sure the same axis is
used in the Volumetric Efficiency Table.
For turbo or super charged engines a couple of preset tables are available in
the Wizard. All provided preset tables should only be used for setting proper
axis values and for start up purposes. Make sure that the ignition timing is
correctly calibrated for your engine before putting load on the engine.
Consult your NIRA i7x dealer for help with the calibration.
Ignition timing is an area of great interest and where a proper calibration can
yield significant power improvements.
It’s very important, however, to make sure the ignition timing is correct since
too much advance can cause significant damage at high loads. The damage
occurs when premature detonation (or knock) happens. Knock is when the
combustion happens too fast and the air-fuel mixture explodes instead of
burning in a controlled fashion.
Knocking results in very high temperatures in the combustion chamber and it
can sometimes chip the surface of the piston. More commonly, though, it can
melt the edges of the piston.
You have to learn how to listen to your engine and hear knocking before you
start modifying the ignition timing.
Advancing the timing increases the efficiency of the engine and lowers the
fuel consumption and yields more engine power. You have to understand
how boost pressure, compression, MAT, the gasoline octane rating, rpm,
air/fuel mixture, load conditions etc. all effect the max ignition advance
before you start modifying the timing.
You can check the ignition timing by entering the same value in the entire
table. Choose a value around 20 degrees of advance. Then connect a timing
light to cylinder 1 to verify that you see the correct advance at the crank
pulley. Naturally, this requires that the pulley has the appropriate markings.
Most engines run well with 20-30 degrees advance in the entire table up to
100 kPa MAP.
It’s beyond the scope of this manual to give any further advice on how to
calibrate ignition timing.
Ignition MAT Compensation
Engines are more knock resistant when the intake air is cooled down.
Compensate the ignition for Manifold Air Temperature in this table.
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