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Knock retard setup


nilsp
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Hi,

Trying to make my knock retard system work.

Have worked on a threshold setup etc, its a very noisy engine, so finding it quite difficult, but feel I`m close to something now, so I turned the knock control on and set ign retard limit to 3.

When testing a little during driving, the knock counter count, and the cyk I knk trim applied retard, but the actual ign and ign table is the same.

I had a dyno run this summer where I noticed this working, but that was the ect ign trim table working.

 

But have to say I`m a little unsure about the settings on this, any obvious errors in setup?

Bosch donut sensor on block, not stock knk sensors on these engines.

4 cyl NA engine, bmw s14

 

Attached a log while doing a pull on road.

pull.llg

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The reason why the logged ignition angle doesnot take knock retard into account is because most users have individual cylinder knock control set up so there is often a different amount of retard applied to each cylinder.  For instance if you had direct spark ignition and individual cylinder knock control set up and you had a logged ign angle of 20deg and a Cyl 1Knk trim of -3deg, then that would mean cyl 2,3,4 had the full 20deg, while cyl 1 would have had 17deg.

I assume you have a distributor with all cylinders allocated to knk trim 1 so you can only retard all cylinders together which maybe makes it a little less intuitive.  In your case all cylinders would have received 17deg using the example numbers above.

Whats the compression and fuel?  I wouldn't have expected these engines to be knock limited...

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Hi Adam,

 

Thanks as usual for detailed answer.

You are right, this is with distributor cap and all cyl allocated to knk trim 1.

Does this mean my ignition actually is retarded in this log?

-even thought the ign angle and ign table is the same where the knk trim seems to retard ign?

 

These engines have tendencies to make lot of noise, and seems to knock quite easily. But yes, many say it shouldnt be a problem.

Therefore I hope Im on the safe side, and hoping to push it a little back having the knock system helping me.

2.66 liter,  11,7 compression, 98 shell v-power.

Attached another log, at this point I could, for first time hear audible pinging.

This is at a very bad tune for the engine, biiiiiig torque dip before coming alive.

bank!.llg

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11 hours ago, nilsp said:

Does this mean my ignition actually is retarded in this log?

-even thought the ign angle and ign table is the same where the knk trim seems to retard ign?

Yes, since "cyl1 knk trim" is allocated to all cylinders in your engine, your actual commanded ignition timing will always be "ign angle + cyl1 knk trim".  So if you had ignition angle = 20deg and cyl 1 knk trim = -3deg logged then the actual final commanded ignition timing would have been 17deg.

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Thanks again for reply.

But if you looked at the log, shouldnt the actual ign go down when knk trim is applied?

-also the knk trim is just quick spikes on 0,1 sec a couple of times.

The advance delay is set to 0,5sec.

This made me unsure if it actually is working the way I set it up?

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34 minutes ago, nilsp said:

But if you looked at the log, shouldnt the actual ign go down when knk trim is applied?

No.  The knock trim is applied on top of the "ign angle" parameter.  I dont know how to explain it any clearer.

 

1 hour ago, nilsp said:

-also the knk trim is just quick spikes on 0,1 sec a couple of times.

The advance delay is set to 0,5sec.

I suspect that was probably an old bug which is why I recommended updating to latest firmware.

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27 minutes ago, Adamw said:

No.  The knock trim is applied on top of the "ign angle" parameter.  I dont know how to explain it any clearer.

 

I suspect that was probably an old bug which is why I recommended updating to latest firmware.

 

ok, I understand :)

Reason for asking is because when I noticed ect ign trim this summer, it was easy to spot on the ign angle vs ign table.

 

I have updated to latest firmware also, but cant remember if that just after this logged run.. will check.

Thanks!

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