I just viewed the last 3 pulls I got from Chris to get a better view of the torque and knock curves. They are totally normal, and you can see that the curvature of the knock level across the RPM range matches the curvature of the torque curve pretty well.

 

Normal knock level? There are about 4 degrees of knock retard up to almost 6k with the stock Hondata tune. Your tune fixed most of that, but still registers 3 degrees of knock retard below 3.5k. It so happens this is where the AFR is still leaner and around 13.5.

 

That's actually not a very significant amount of knock retard. It's common for totally stock '06+ AP2's to have that much knock retard. Knock retard is not an indication of actual knock. Knock retard is determined by several lookup tables in the tune and adjusted by some calculated / observed parameters. The reason why my tune has less knock retard above 3600 is because VTEC is engaged. The knock sensitivity tables are more conservative on the low cam, which is why the Hondata tune is showing so much knock retard higher in the rev range.

 

If you are getting false knock at low rpms then the sensitivity can be adjusted in Flash Pro.

 

That's more likely to turn false knock into REAL knock. Reducing the knock sensitivity will cause the knock retard to decrease, which will cause actual ignition timing to be more advanced. If your ignition timing is already advanced to the point it needs to be, then the additional timing advance will not be good.

 

Thats not a problem if you tune the base tables to the correct timing. Lower the timing a bunch and desensitize the knock sensor at those rpms until false knock is gone. Then tune for mbt from there while still monitoring knock retard

Either way gets the same results, but id rather not be seeing false knock in the logs.

 

Why not just disable the knock sensor? It seems that you don't understand what "Knock Retard" is, since it is NOT a measure of knock. Unless you are running super high octane fuel from a lab, there should always be some knock retard. That's how the ECU automatically adjusts ignition timing based on the observed octane level. If you adjust the knock sensitivity to the point that knock retard goes away, the ECU will no longer make automatic adjustments to timing for Octane.

I spent quite a bit of effort studying cause and effect for each of the knock tables, and I never saw any indication that the knock tables actually changed the ECU's definition of a "knock count". What I did see is that reducing knock sensitivity tended to increase knock counts, since the ECU would not apply enough knock retard to prevent knock.

Honestly, I think the name "Knock Retard" makes it confusing. I think a better name for that value would be "Octane Ignition Trim"

 

Disabling the knock sensor is not the same as desensitizing it. Any modifications to the engine will affect the engine noise level and could trigger false knock. That is why running the engine with a known amount of advance that will not cause knock is important to fine tune the sensitivity so the knock sensor is actually useful. Have youe ever tuned a newer SI with a jrsc on flashpro? They trigger a ton of false knock at low rpms and the sensor must be desensitized in that area of the map or you will get unecessary knock retard.

There is a "knock ignition limit" that was determined by Honda testing for maximum spark advance before knock using the max likely octane fuel to be used on the street. This ignition limit if negative is retarded from the base timing tables. It does not show up as knock retard though when logging.

If you are running a super high octane race fuel and the knock retard goes away then that means you were in fact getting knock.

 

I wasn't trying to say disabling the knock sensor is the same as desensitizing it. I was being sarcastic.

The last sentence you wrote is utterly incorrect. The only time there should be no knock retard is when you are running super high octane race fuel. If you aren't running super high octane race fuel, then a good tune will apply knock retard (Octane Ignition Trim). That's a fact!

Optimal timing changes with octane, so you can't assume "base timing" is constant. Honda's knock control is designed to automatically adjust ignition timing UP and DOWN to compensate for the fuel it's running at the time. There isn't a "Knock Advance" value, so if you zero out the knock retard, the ECU can't ADVANCE timing when you run higher octane fuel.

 

BTW, there was never a SC'ed Civic Si produced by Honda, so the stock knock tables couldn't be correct for an SC application. The stock knock tables would absolutely have to be tweaked, but it should still have a healthy amount of knock retard while running pump gas!