Sorry mate, i'll leave that one to JB. don't know enough about the inner workings.
However even though its wastespark it would have to still fire at twice the rate due to there being half the coils.

Let me know if you need any testing on the rom.

 

damn closed the wrong window.

ok so the CT9A coils spark both cylinders, hence the wastespark comment?

I wonder if that extra energy required means a longer DWELL time to generate it...

 

Yep, both cylinders simultaneously.
Unsure about the longer dwell time, I would expect that would be the case though.

 

That is my understanding because it fires whether it needs to or not.

 

The dwell time has nothing to do with wasted spark or COP until you reach the point where engine RPM is high enough that complete coil charging can no longer take place.

If the COP coils don't charge any differently then the wasted spark coils, then they would need the same dwell time.

The question is, does the COP coil charge faster then the wasted spark coil?

At 8000 RPM, the engine has 7.5ms that it could charge the coils. From what I've found, most modern coils require 4ms or less, leaving ample time on a wasted spark setup. The only down side and potentially why they may limit the dwell time at high RPM is that the coil is on more in a given period of time which will build up heat in the coil, even if field saturation does not take place.

If we still need scaling on these tables, simply hooking up an o-scope would give you what you need. The dwell is constant below 2800 RPM. Just grab a log at a stable engine speed where voltage isn't varying and watch with the O-scope. Measure out the pulsewidth with the O-scope and you'll be able to relate it to the final dwell value that comes out of these tables.

 

well with multiple plugs running of the one coil its a bit tricky.

when you stop charging the coil it tries to spark, if you dont charge it long enough then it would have enough energy to spark.

now if you start charging whilst the spark is happening then you cut the spark short and you also dont loose the whole charge...

 

So, playing arround with the coil tables today, I wanted to try and verify Erics take on how the second table is applied.
I have thought it was correct since posted but never got arround to playing with it.

My testing agrees with his, to sumarise:
The Dwell-Time stays (more-or-less) constant at 3.46mS (as per the stock base dwell table) up to 2800rpm (the dwell reduction threshold) and then gradually reduces down to 2.7mS at 6500rpm.

I then reduced the 14volt cell in the second table, Dwell-Time Reduction factor, from 0.137 to 0.037.
This produced a Dwell-Time of 3.0mS at 7500rpm. So reducing the values in the second table changes the reduction gradient.

This was the result I wanted so Im happy. Arron seems to be geting the results he wants by upping the main dwell table but I was attempting to boost the spark at the high rpm end only.
This was on my Evo9 with M&W COP setup but the general principals will hold for the stock coil setup.

 

The dwell setting shouldn't matter at all with the M&W CDI ignition box.

All it looks for is a falling edge. The M&W box takes care of everything else on it's own.

 

I am using non-CDI type coil on plug (and likeing it!)

 

nice work here. what about 9626 v7 Dave it never gets any love

 

Can you post a screen shot of this change?

 

Relocate to 9055 v7 Tim.

 

Here are some scripts to add to your xmls.
I have included the second correction, though I dont understand how it works at present.
I am confident on the scaling though, weird as they may be.

<!-- IGNITION COIL DWELL-TIME TABLES -->


<!-- SCALINGS -->

<scaling name="ChargeTime" units="mS" toexpr="x*0.064" frexpr="x/0.064" format="%.2f" min="0" max="16.32" inc="0.064" storagetype="uint8" endian="big"/>

<scaling name="BatteryVoltage" units="Volts" toexpr="x*75/1024" frexpr="x*1024/75" format="%.2f" min="0" max="18.75" inc="0.5" storagetype="uint16" endian="big"/>

<scaling name="CF256" units="Correction Factor" toexpr="x/256" frexpr="x*256" format="%.3f" min="0" max="2" inc="0.0039" storagetype="uint8" endian="big"/>

<scaling name="Percent128" units="%" toexpr="x/1.28" frexpr="x*1.28" format="%.0f" min="0" max="100" inc="1" storagetype="uint8" endian="big"/>

<scaling name="BattVoltDwell%" units="%" toexpr="x*75/1024" frexpr="x*1024/75" format="%.2f" min="0" max="18.75" inc="0.5" storagetype="uint16" endian="big"/>

<scaling name="RPMLimit" units="RPM" toexpr="7500000/x" frexpr="7500000/x" format="%.0f" min="0" max="9000" inc="60" storagetype="uint16" endian="big"/>




<!--
Evo6
25570000
-->

<table name="Ignition Coil, Dwell-Time" address="1229e" category="Timing" type="2D" scaling="ChargeTime">
<table name="Battery" address="2c7c8" type="Y Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell-Time Reduction RPM" category="Timing" address="10A46" type="1D" scaling="RPMLimit"/>

<table name="Ignition Coil, Dwell-Time Reduction Factor" address="122ac" category="Timing" type="2D" scaling="CF256">
<table name="Battery" address="2c7c8" type="Y Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell-Time Correction 2" address="122ba" category="Timing" type="2D" scaling="Percent128">
<table name="Battery" address="2c7c8" type="Y Axis" elements="9" scaling="BattVoltDwell%"/>
</table>




<!--
Evo7
90550001
98640014
-->

<table name="Ignition Coil Dwell Time" address="404e" category="Timing" type="2D" scaling="ChargeTime">
<table name="Battery" address="4f34" type="Y Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell-Time Reduction RPM" category="Timing" address="1746" type="1D" scaling="RPMLimit"/>

<table name="Ignition Coil, Dwell-Time Reduction Factor" address="405e" category="Timing" type="2D" scaling="CF256">
<table name="Battery" address="4f34" type="Y Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell-Time Correction 2" address="406e" category="Timing" type="2D" scaling="Percent128">
<table name="Battery" address="4f34" type="Y Axis" elements="9" scaling="BattVoltDwell%"/>
</table>




<!--
Evo8
96260009
96260012
-->

<table name="Ignition Coil, Dwell-Time" address="3e4e" category="Timing" type="2D" scaling="ChargeTime">
<table name="Battery" address="5aac" type="Y Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell-Time Reduction RPM" category="Timing" address="1746" type="1D" scaling="RPMLimit"/>

<table name="Ignition Coil, Dwell-Time Reduction Factor" address="3e5e" category="Timing" type="2D" scaling="CF256">
<table name="Battery" address="5aac" type="Y Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell-Time Correction 2" category="Ignition Coil" address="3e6e" type="2D" scaling="Percent128">
<table name="Battery" address="5aac" type="X Axis" elements="9" scaling="BattVoltDwell%"/>
</table>




<!--
Evo8
94170008
-->

<table name="Ignition Coil, Dwell-Time" address="41ea" category="Ignition Coil" type="2D" scaling="ChargeTime">
<table name="Battery" address="6398" type="Y Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell-Time Reduction RPM" category="Timing" address="1746" type="1D" scaling="RPMLimit"/>


<table name="Ignition Coil, Dwell-Time Reduction Factor" address="41fa" category="Ignition Coil" type="2D" scaling="CF256">
<table name="Battery" address="6398" type="Y Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell-Time Correction 2" category="Ignition Coil" address="420a" type="2D" scaling="Percent128">
<table name="Battery" address="6398" type="X Axis" elements="9" scaling="BattVoltDwell%"/>
</table>



<!--
Evo8
94170015
-->

<table name="Ignition Coil, Dwell-Time" category="Ignition Coil" address="41ea" type="2D" scaling="ChargeTime">
<table name="Battery" address="69bc" type="X Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil - Dwell-Time Reduction RPM" category="Timing" address="1746" type="1D" scaling="RPMLimit"/>

<table name="Ignition Coil, Dwell-Time Reduction Factor" category="Ignition Coil" address="41fa" type="2D" scaling="CF256">
<table name="Battery" address="69bc" type="X Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell-Time Correction 2" category="Ignition Coil" address="420a" type="2D" scaling="Percent128">
<table name="Battery" address="69bc" type="X Axis" elements="9" scaling="BattVoltDwell%"/>
</table>




<!--
Evo8
96530006
-->

<table name="Ignition Coil, Dwell-Time" address="41ea" category="Ignition Coil" type="2D" scaling="ChargeTime">
<table name="Battery" address="6808" type="Y Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell-Time Reduction RPM" category="Timing" address="1746" type="1D" scaling="RPMLimit"/>

<table name="Ignition Coil, Dwell-Time Reduction Factor" address="41fa" category="Ignition Coil" type="2D" scaling="CF256">
<table name="Battery" address="6808" type="Y Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell-Time Correction 2" category="Ignition Coil" address="420a" type="2D" scaling="Percent128">
<table name="Battery" address="6808" type="X Axis" elements="9" scaling="BattVoltDwell%"/>
</table>




<!--
Evo9
88580013
88580014
-->

<table name="Ignition Coil, Dwell-Time" category="Timing" address="3cc6" type="2D" scaling="ChargeTime">
<table name="Battery" address="6f14" type="Y Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell-Time Reduction RPM" category="Timing" address="1346" type="1D" scaling="RPMLimit"/>

<table name="Ignition Coil, Dwell-Time Reduction Factor" category="Timing" address="3cd6" type="2D" scaling="CF256">
<table name="Battery" address="6f14" type="Y Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell Time Correction 2" category="Timing" address="3ce6" type="2D" scaling="Percent128">
<table name="Battery" address="6f14" type="Y Axis" elements="9" scaling="BattVoltDwell%"/>
</table>



<!--
Evo9
88590015
-->

<table name="Ignition Coil, Dwell-Time" category="Timing" address="3cc6" type="2D" scaling="ChargeTime">
<table name="Battery" address="6e0c" type="Y Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell-Time Reduction RPM" category="Timing" address="1346" type="1D" scaling="RPMLimit"/>

<table name="Ignition Coil, Dwell-Time Reduction Factor" category="Timing" address="3cd6" type="2D" scaling="CF256">
<table name="Battery" address="6e0c" type="Y Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell-Time Correction 2" category="Timing" address="3ce6" type="2D" scaling="Percent128">
<table name="Battery" address="6e0c" type="Y Axis" elements="9" scaling="BattVoltDwell%"/>
</table>




<!--
Evo9
98280002
-->

<table name="Ignition Coil, Dwell-Time" category="Timing" address="35FC" type="2D" scaling="ChargeTime">
<table name="Battery" address="5F00" type="Y Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell-Time Reduction RPM" category="Timing" address="1346" type="1D" scaling="RPMLimit"/>

<table name="Ignition Coil, Dwell-Time Reduction Factor" category="Timing" address="360C" type="2D" scaling="CF256">
<table name="Battery" address="5F00" type="Y Axis" elements="9" scaling="BatteryVoltage"/>
</table>

<table name="Ignition Coil, Dwell-Time Correction 2" category="Timing" address="361C" type="2D" scaling="Percent128">
<table name="Battery" address="5F00" type="Y Axis" elements="9" scaling="BattVoltDwell%"/>
</table>

 

With regard to the Dwell-Time Reduction table, as it is typically applied to Evos may not be the best result.

For example, stock evo values give less Dwell-Time at lower battery voltages than high battery voltages. This seems a bit counter-intuative as you would think higher Battey voltage should require less Dwell-Time and would also reduce coil heating.

And at lower battery voltages you would want the full Dwell-Time, not further reduction in Dwell-Time.

It happens that Mitsubishi have tweaked some ROMs something like this.
Some ROMs have the 9-12v cells set to 0.0, giving no dwell reduction at these voltages.
The values from 14v-18v are held fairly constant giving the same reduction rate irrespective of battery voltage.

Food for thought.

 

I have the 88590015 ROM so I assume this new XML code replaces what I used based on what was provided in Post #1. Please advise.