some knocks and wonder how IGN value is calculated

Calibrations for FlashPro Manager - Use all calibrations at your own risk (dyno tuning recommended)

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lorem
Posts: 18
Joined: Sat Mar 05, 2016 11:52 pm

some knocks and wonder how IGN value is calculated

Post by lorem » Thu Mar 17, 2016 11:27 am

Hi,

I reflashed my stock 2015 Accord V6 AT with the "hondata tuned" tune. I have 91 octane gas. Now I'm looking at some knocks happening. There are about 10 of them in a few miles I drove. A few knocks also happens with factory tune.

Knocks seem mostly happen around 1500-1750rpm and column 7-8. I retarded the ignition timing of that area a little but am still getting a few knocks. The current knock control value is about 51%. I hope some of you can help take a look and see if that's normal or suggest some adjustments.

There is also a mystery how the actual ignition timing (IGN) is calculated. At some points I found the ignition timing is more than the numbers in the ignition table. For example this one:
Screen Shot 2016-03-17 at 11.18.45 AM.png
Screen Shot 2016-03-17 at 11.18.45 AM.png (112.34 KiB) Viewed 2693 times
The ignition table highlights numbers 27, 22.5, 28 and 25, but IGN is 35. A second knock happened soon after that. So I guess there must be some other parameters which could add to the ignition timing?
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datalog0004.fpdl
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Spunkster
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Re: some knocks and wonder how IGN value is calculated

Post by Spunkster » Fri Mar 18, 2016 10:25 am

It is most likely the knock igniotion limit tables: https://www.hondata.com/help/flashpro/k ... on%2Blimit

They can add timing if the conditions are right.

lorem
Posts: 18
Joined: Sat Mar 05, 2016 11:52 pm

Re: some knocks and wonder how IGN value is calculated

Post by lorem » Fri Mar 18, 2016 10:54 am

It's strange that it adds to the ignition table numbers. According to the manual, the ignition table contains the timing for the best performance. So adding time to it will decrease performance unless the knock limit is negative. But for that particular spot, the knock limit is positive number.

https://www.hondata.com/help/flashpro/i ... tables.htm

shind3
Posts: 109
Joined: Mon Jun 30, 2014 8:02 am
Location: Pittsburgh, PA

Re: some knocks and wonder how IGN value is calculated

Post by shind3 » Thu May 12, 2016 9:43 am

Newer ECUs make a distinction between 'cruise' and 'accel' and run different ignition maps etc. Subaru is one such example.

Hondata should be able to trace the code in IDA a little better and confirm your 2015+ Honda does not share the exact same ignition timing logic as the older Hondas... Because it is quite clear from your datalogs that the following formula is incorrect for your 2015 V6 Accord.
Hondata wrote:Ignition advance = minimum(MBT Ignition, MBT Ignition + knock ignition limit - (knock retard x knock control))

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