Dwell time in the GTR is set by calculating the desired dwell time and comparing it to heat restriction dwell time calculated by the ECU, it will then use whichever is lowest and limit it by a maximum and minimum value of crank degrees.

Primary Dwell Calculation

The desired Primary dwell angle uses the following calculation

Dwell Heat Restriction Calculation

The heat restriction dwell angle is calculated using the following formula

The Heat constant could be adjusted as a global variable to remove the restriction on coil temperature limit estimation

The battery voltage or engine speed factors can be increased to allow angle increase to be set in very specific conditions

Dwell Limit Calculation

The final dwell angle is set to the lowest applicable value of either Heat or Desired and the Min (6°) and max (114°) angle limits applied.

Dwell Angle to Dwell Time Conversion

It is much more common to use dwell time as opposed to dwell angle when calibrating aftermarket coils or increase the energy output of standard coils. To calculate the dwell time from angle, use the formula below

𝐷𝑤𝑒𝑙𝑙 (𝑚𝑠) = 𝐷𝑤𝑒𝑙𝑙 𝐴𝑛𝑔𝑙𝑒 (°) × (166.6666 / 𝑅𝑃𝑀)

So at 50deg dwell and 2000RPM there is a dwell time of 4.166ms.

Increasing Dwell Time

To extend the dwell angle you will need to adjust the coil voltage constant value (increase) as well as (increase) the heat restriction engine speed and voltage factor map values to extend the limit at the engine speeds and voltages you require. there is also a worksheet that calculated the basic dwell time using the above formulas and map values.  in this worksheeet you can enter values and change constants and it outputs a value for dwell time and let you know what limit is applied