BMW M62 Wasted Spark

EMU BLACK / CLASSIC
1

Hello Everyone,

I am hoping someone can help me with setting up wasted spark for my m62 project.

So in short, what cylinders do I pair to make wasted spark work.

I understand its 360 degree opposite but I am a bit of a noob not sure how to calculate this and if I get it wrong the harness will have to reworked…

Thanks in advance!

Butch

2

What coils are you going to use and why not just set it up like it is from the factory with a coil on every cylinder?

3

Nothing to do with the coils… ecublack doesnt have enough circuits to run the coils 1:1 so the idea is to share the circuits between cylinders so in essence the v8 becomes a v4. I just dont know which cylinders to pair and while I can google it, not sure if what i am getting is correct. So… I am asking here in case someone knows definitively or how to compute for it since they typically have to be 360 degrees paired

4

Just google the firing order of the M62 and pair them up accordingly to each respective ignition output 1-4

Also it will matter what type of wasted spark coils you will use because they are not all the same. Some can feed four cylinders while others will only feed two cylinders. So you can end up needing to run two coils or 4 depending on which you use.

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5

360 degrees is only half the cycle on a 4-cycle engine. You need 720 degrees to fire every cylinder at least once. Divide that number by the amount of cylinders and you will get the degrees at when each cylinder will fire given you know the firing order.

720/8=90 so every 90 degrees a cylinder will fire.

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6

If I understand you correctly, the m62 has a coil per cylinder the ecu triggers the paired coils at the same time. Of the pair one will correspond to the compression cycle the other will be wasted.

I just need to work out which cylinders to pair. I’ll try the formula you mentioned, thank you

7

It really is up To you how you want to wire everything up.

  1. If you want to run 8 individual coils, you would need to use 4 ignition outputs fired in pairs (wasted spark)
  2. If you wanted to run four “2-post” wasted spark coils (each having 2 spark plug outputs) you could do that and use 4 ignition outputs.
  3. If you wanted to run two “4-post” wasted spark coils (each having 4 spark plug outputs) you could do that and use 4 ignition outputs.

As you can see there are multiple ways to go about it. Just depends on your packaging and what you want it to look like really. Once you find the firing order you can simply pair the two cylinders together that would essentially be 360 degrees “out” from each other.

For example, for arguments sake if the firing order was 1-2-3-4-5-6-7-8

you would pair 1-5, 2-6, 3-7, 4-8

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8

Cylinder pairs for M6X :
1-6
2-8
3-5
4-7

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9

Thank you very much, cheers

10

I see that you have been provided the wasted spark configuration for this engine but you never really had your original question answered that would help you understand where to waste the spark.

Obviously the ‘useful’ spark should fire at the top of the compression stroke. No need to explain. I’m sure you understand this.

The wasted spark should have no opportunity to ignite fuel. This means it must fire into the exhaust stroke.

So always pair the 2 cylinders that are at compression and Exhaust at the same time.

11

Got it thank you… that actually makes it easier to figure out. Even if you just looked at the cylinders while rotating the crank! Cheers

Thanks again everyone for taking the time to reply, much appreciated!