Si Knock Airflow Limit Table

[PowerPerLiter]

I am unsure if Ktuner has this table in their software or not but with my Flashpro I have access to this table and have noticed the variations within the provided can tunes that Hondata made and provided us. This table references actual measured "cylinder fill" or "air charge" within each cylinder against rpm and knock retard. I am assuming this places an effective cap of allowable cylinder fill at different knock retard amounts.

My question is can this number be too high assuming no detonation? I have asked in the Hondata board and it was alluded that it is a command function as well as a "limit".

This tells me that maybe it has an effect on camshaft angle depending on the command of air charge?

Hondata says that this table cannot limit boost pressure directly.

I cant think of another way to directly effect cylinder fill other than valve overlap.

Anyone care to brain storm this with me that may be "in the know"?

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[PowerPerLiter]

The other option I could see is its only directly for knock control and if the "limit" is exceeded then knock control starts to go up?

What do the computers do when this number is exceeded?

 

[SouthSideBeef]

I wish I knew more and could contribute to your (high quality) posts. I'm slowly learning more about tuning and cars in general but it's a long process. Unfortunately for the current topic I dont really know what your talking about. Hopefully someone else can contribute.

 

[PowerPerLiter]

Thanks buddy. I guess I just try to ask the questions that nobody else is. Maybe one day it will be easily google searched and lead to some answers. Usually if I ask something its in last resort as I have exhausted all other avenues of research. I usually dont expect an answer unless it comes from ktuner themselves. I have seen them step up to answer stuff they dont even have to....excellent company.

There just is not a lot of info available to us yet....one day...lol

 

[Myx]

@PowerPerLiter

Have you found out any more information around this?

 

[PowerPerLiter]

@PowerPerLiter

Have you found out any more information around this?

Unfortunately no. I dont even think there is a complete answer to be had by the "company men".

 

[D-RobIMW]

Raising and lowering this has no effect on camshaft phasing.

It simply defines the maximum cylinder fill at an engine speed versus knock retard (as you mentioned before).

If you're not getting uncommanded throttle closures at WOT, don't bother touching it.

 

[PowerPerLiter]

Awesome sauce. I way over thought it then. Thats almost disappointing lol.

 

[PowerPerLiter]

@Myx there ya go buddy. Much simpler than I figured.

 

[PowerPerLiter]

@D-RobIMW I was thinking possibly it could serve as a secondary torque table that raised or lowered actual cylinder pressure via valve event timing/overlap referencing the other knock tables. Now I understand it doesn't.

Hondata could have simply stated it's a table that uses the throttle plate to limit cylinder filling. If your exceeding the value bump the number within reason.

What if it's set to a "unachievable" number? Say 2000?

 

[varge]

One of the functions of increasing k.control is to retard timing to protect the engine. I guess the cylinder fill limitation is sort of an emergency exit in case ignition retard is not able to control knock (or fear of knock - whatever) and then the ECU can just close the throttle to lower the load and possibly save your pistons from melting. I don't think there is much reason to change these unless using a big turbo, the stock one can't quite overfill the cylinders I think.

 

[D-RobIMW]

One of the functions of increasing k.control is to retard timing to protect the engine. I guess the cylinder fill limitation is sort of an emergency exit in case ignition retard is not able to control knock (or fear of knock - whatever) and then the ECU can just close the throttle to lower the load and possibly save your pistons from melting. I don't think there is much reason to change these unless using a big turbo, the stock one can't quite overfill the cylinders I think.

This, exactly.

 

[D-RobIMW]

@D-RobIMW I was thinking possibly it could serve as a secondary torque table that raised or lowered actual cylinder pressure via valve event timing/overlap referencing the other knock tables. Now I understand it doesn't.

Hondata could have simply stated it's a table that uses the throttle plate to limit cylinder filling. If your exceeding the value bump the number within reason.

What if it's set to a "unachievable" number? Say 2000?

You can set it as high as you want, for the most part. It wont change anything unless you're exceeding the limit. If you exceed the limit for a given engine speed and knock retard value, the throttle plate will close, which in turn lowers commanded boost pressure also.

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