Adjusting the knock sensitivity tables in FlashPro

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Apr 22, 2010 | 09:26 AM

#11

TheNick

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Joined: Jun 2008

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Quote:

Originally Posted by TheNick,Apr 21 2010, 09:38 AM

I'm going through the same thing right now Greg. I've got my AFR's where I want them but I'm still getting a lot of knock retard on the low cam - but no knock counts on either the high or the low. My tuner had reduced the knock sensitivity on the high cam pretty significantly because of some issues with my valves being rather loud.

So I increased my knock sensitivity, and finally got some knock counts on Cylinder 3 on the high cam - I then reduced the ignition by one degree on that cylinder and increased the knock sensitivity by 5% again on the high cam.

I plan to continue playing around with this on the high cam and WOT, once I get that figured out and I get my knock sensitivity back up near the stock levels - I'll be happy. Then I'll start on the low cam/partial throttle and try reducing the knock sensitivity - I'm not getting any knock counts - but I am getting knock retard there - which doesn't make a whole lot of sense but I figure I can reduce the sensitivity if I'm not getting knock counts without damaging the motor.

So I just drove the car with the new tune.

No more knock counts (retarded ignition by 1deg and add 1% fuel to Cyl 3). But MORE knock retard with increased knock sensitivity. Knock levels at WOT are in the 60-70% region which seem consistent with Greg's plots.

This sure is weird, seems like the sensitivity is directly related to what the ECU is anticipating. Anyone have a phone number for the Honda Engineers?

Apr 22, 2010 | 01:02 PM

#12

Hondata

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Joined: Jul 2001

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From: Torrance

There's another thread on this, but in short, the knock sensitivity will determine the amount of knock retard, but does not affect the knock count. The ECU has MBT ignition table (mean best torque = the ignition table we usually edit) and also a calculated ignition limit for detonation. The lower of calculated ignition limit and MBT ignition is used, with the difference showing as knock retard. Changing the knock sensitivity table alters the calculated ignition limit and so can reduce the knock retard. Also the amount of knock noise will shift the calculated ignition limit up or down as the ECU estimates the fuel octane. I wish that Honda had used a better knock control method, but I suspect that the best had already been patented by other companies.