Maximum trailing

This is for rotary engines and prevents the trailing degrees from being adjusted to far from the leading plugs. In piston engines this block is hidden.

Maximum Timing

This is the maximum combined timing allowed in degrees by all the timing maps combined. If the graphs are tuned for more degrees, it will be limited by this value. On the Timing Matrix this will also prevent the tuner from selecting higher values there.

Minimum coil time

This is the minimum coil charge time which the tuner can select. The ECU will vary the charge time automatically according to engine load from the minimum to the maximum value. It can be adjusted in 0.1 millisecond intervals from 1ms to 5ms. Standard coil setting is about 60% from the maximum value. Example if Max value is 3ms then make min 1.8ms. see the Maximum Coil Time to determine the right setting.

Maximum coil time

This is the maximum coil charge time which the tuner can select. The ECU will vary the charge time automatically according to engine load from the minimum to the maximum value. It can be adjusted in 0.1 millisecond intervals from 1ms to 5ms. Standard coil setting is 2.5 to 3.5 milliseconds for coils of around 0.9 ohms but some new coils are lower resistance and may need shorter times. Normally the driver will heat up and may damage if it runs too hot. Always start with a min value if you are not sure. Start with 2.0 to 2.5ms. Coils with a lower resistance in the 0.4 to 0.5-ohm region, use a value of 1.5 to 2ms. Always a good idea to put a 5-Amp fuse in the power line of each coil. If you go too high the fuse will blow. If you use the Mercury Coil driver, then you can look at the overload LED. It comes on at 4-amp current. Most coils are rated at 5.5A. adjust maximum so that the OVL LED may come on at full load but not on at less than 70% load. During cold starting, this maximum value is used till the engine reaches 60°C. Thereafter spark control will commence.

Vacuum Timing Split

This value sets the RPM split between the Low & High Vacuum Timing maps. This value is selected about 500 to 1000 RPM’s above idling.

Altitude comp.

This value sets the timing advance ratio for every 1000 meter above sea level. A value of 3 means that the timing will be advanced by 6 degrees at 2000 meter above sea level. If you tune the vehicle at a higher altitude, make sure this value is set. Then when the driver descends to lower altitude the ECU will retard the timing automatically.