Sequencing Batch Fired Coils (Wasted Spark) with Wolf3D

[RTz]

First, some definitions for the chart below....

 

"Ignition 1 Pulse Offset" means ignition channel 1, "Ignition 2 Pulse Offset" means ignition channel 2, etc, etc.

 

In this example, were only using 3 coils on an even-fire 6 cylinder. That means the remaining channels can be turned off... entering a value of 255 switches that channel off (Note: this example chart is a V4+, so there are only 6 available channels, rather than 8 for V500).

 

"Ignition 1 Pulse Skip" is how many 'slots' on the trigger disc you want the ignition channel to skip before firing again. In this example, you want to skip 2, so the same coil will fire again 180 (cam) degrees later (same as 360 crank degrees). More on this later.

 

 

 

 

 

Take a look at the trigger disc below. In this example, it spins counter-clockwise, triggered on the rising edge (the varying slot lengths make no difference when configuring this way)...

 

 

 

The blue numbers near each slot are how the ECU see's them, numerically. The "Dual Pulse" slot will ALWAYS be "0". The next slot will always be "1", the next "2", and so on.

 

Putting the two together is where the magic happens. The red circles below would be the first ignition event. What they mean is that the 1st ignition channel will fire relative to slot "0", then skip two slots and fire again. Meanwhile, the second coil will fire relative to slot "1", and again relative to slot "4". And, you guessed it, the 3rd coil will fire relative to slot "2" and again relative to slot "5".

 

 

 

 

Why am I saying "relative"? Because there is another software parameter called "REF Degrees BTDC". The combination of this number and your timing map will be actual timing relative to the slots. I'll come back to this later.

 

So, If your coils are wired like this...

 

Channel 1, coil for cylinder 1 & 6

Channel 2, coil for cylinder 2 & 5

Channel 3, coil for cylinder 3 & 4

 

...the above 'order' given in the chart above is correct. Notice I didn't say sequence. I said order, as in firing order. However you're not done yet. You still need to get them in proper 'time'... If you change the first three numbers to 1,2,3. The firing order will remain the same, BUT the events will happen 120 (crank) degrees LATER. If you changed the first three numbers to 5,0,1 (look at the slot numbers in blue), the firing events will start 120 (crank) degrees EARLIER.

 

Note: When changing the sequencing, you must turn the ECU off and back on. Wolf will not allow a sequencing change on the fly.

 

When you're ready to time your engine, unplug the injectors and turn on "timing lock" in the software. Set it to zero degrees. Put your timing light on cylinder one and see where the timing indicator lands. If it is 'close' to 0, you may be able to bring it to 0 with a combination of adjusting "REF Degrees BTDC" and mechanical adjustment of the trigger. If it is a 'long way's out', then change the sequencing to bring it close enough so that you can.

 

 

Back to "REF Degrees BTDC". This parameter exists for one reason... the ECU can't go back in time. In other words, when your timing map requests 30 degrees BTDC, it needs to know where 30 degrees BTDC is BEFORE the engine gets there, not AFTER it's already passed by. Make sense? Hence, "REF Degrees BTDC" must be at least as many degrees as the maximum advance you plan to run. For example, max advance under cruise conditions could be as high as 55 degrees BTDC. In that case, "REF Degrees BTDC" must be equal to or greater than 55 degrees.

Edited October 10, 2009 by RTz

[MONGO510]

Does this mean your M-Powered Z Lives?

 

Mongo

[RTz]

Does this mean your M-Powered Z Lives?

 

Wishful thinking? I'll drink to that