Knock control - load vs RPM table found
Mar 16, 2011, 12:25 AM
#346
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Need Help - Knock Tables and Address for Evo9 JDM 89820002
Dear All, I have be spending hours and hours going thru all the address posted in this forum for my Evo9JDM 89280002 without sucess. Does anyone out there with the knock table address for this ECU. Please help.
Jun 18, 2013, 06:13 PM
#348
So it is a full throttle pull from 3000 RPM to 7000 RPM approx (x-axis).
The very spiky tracein blue is the knock voltage if you like. I presume it will be bandpass filtered and rectified. Then a gated integrator of the knock sensor signal for each ignition event.
Yellow is a moving average of the knock voltage. Cyan is a moving average of that. This is then used to calculate knockbase which is in magenta.
The mult, add1 and add2 are looked up by RPM from the tables I posted earlier in this thread.
Knockbase=(mult*knockvar2/8) + Add1 or Add2
Add1 is used before the gain is reduced (at about knockbase 140 or about 4800 RPM on this particular trace), Add2 is used after the gain is reduced.
Testing this for example at 6000 RPM reading the numbers off the graph:
knockbase=(19*40/8)+7=102 which is about what knockbase actually is on the graph at about 6000 RPM.
The very spiky tracein blue is the knock voltage if you like. I presume it will be bandpass filtered and rectified. Then a gated integrator of the knock sensor signal for each ignition event.
Yellow is a moving average of the knock voltage. Cyan is a moving average of that. This is then used to calculate knockbase which is in magenta.
The mult, add1 and add2 are looked up by RPM from the tables I posted earlier in this thread.
Knockbase=(mult*knockvar2/8) + Add1 or Add2
Add1 is used before the gain is reduced (at about knockbase 140 or about 4800 RPM on this particular trace), Add2 is used after the gain is reduced.
Testing this for example at 6000 RPM reading the numbers off the graph:
knockbase=(19*40/8)+7=102 which is about what knockbase actually is on the graph at about 6000 RPM.
I tried logging the knock parameters preloaded in evoscan (i.e; knock_var, knock_72,etc) and most don't record anything at all.
-Jamie
Jun 21, 2013, 02:27 PM
#349
Evolved Member
I logged in OP2 direct to the SD card, but that logging is way to slow to be any use for analysis, peaks can so easily be missed.
Jun 21, 2013, 03:23 PM
#350
Need AEM internal datalogging speed, what is it 1000hz or something? Even 250 would be better.
The best method of those moments that are "hmmm" is use the dyno as the tool. Pull timing and see what it does. No power change - didnt need to be there anyway and most likely real spike without knock. Power drop - timing was probably okay. Timing drop and power increase - stop playing with knock control numbers and trying to crack pistons or pound bearings out.
Using a couple gallons of 110 octane with no changes is another way to determine if the knock was real or not. Same outline as before, no change timing is on. Power drop timing is low (flame front is slower on high octane and power will drop as octane rating is to high for the engine needs) power increase timing was too high and engine was detonating.
The best method of those moments that are "hmmm" is use the dyno as the tool. Pull timing and see what it does. No power change - didnt need to be there anyway and most likely real spike without knock. Power drop - timing was probably okay. Timing drop and power increase - stop playing with knock control numbers and trying to crack pistons or pound bearings out.
Using a couple gallons of 110 octane with no changes is another way to determine if the knock was real or not. Same outline as before, no change timing is on. Power drop timing is low (flame front is slower on high octane and power will drop as octane rating is to high for the engine needs) power increase timing was too high and engine was detonating.
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