Question for Doc or Steve,

Is it possible that the ion sensing knock retard system can be applying an inappropriate or incorrect amount of knock retard if my bikes build is of a higher compression than than the base map I've loaded? My HQ 113" build is supposed to be 10.5-1 on a 07 Ultra with D&D Fat Cats

I've started with MAP NL176-002-B1.MT7, I don't know what the compression is supposed to be for this map/build but wondering if the ECM is comparing ION SENSING data against a table within the ECM or does the ION SENSING analize the "rate" of pressure rise in the cylinder?

So, long story short, could the ECM be applying inappropriate KNOCK RETARD,,,,,,,,, if so do I go to tuning the timing tables "by ear", listening for the faint tinklings of ping starting? No dyno to measure torque output at the different timing settings, have to do this on the road and by using the "dyno" in the TTS Datamaster.

I just wrote a long explaination of this and losst it all for some reason....I'll be back later to try again.

Doc

Ok lets try this again but I'll keep it short.
The Spark Knock pulls timing when the ECM reads abnormal combustion which is measured in Ion activity, high Ion activity is normal combustion and low Ion activity is abnormal Combustion and yes it is pressures in the chamber.
Abnormal combustion Can be caused by too much advanced timing, too lean of fuel mixture or both. Ve tables that are not set correctly will cause problems with the fuel delivery and through the math off in the map, not enough accelerator fuel will cause abnormal Ion activity also while under a load rolling on the throttle as we all know. However low pressures or Ion activity can also be triggered by a bad head design and the ECM will pull timing because thats all it knows what to do in that situation. For an example, A head with poor turbulence can cause poor combustion in certain parts of the power range, we see this a lot with high performance builds with a bad combination of parts. If you see Spark retard in a recording that is above 7 or 8 degrees for an example but you don't hear pinging chances are it is caused by the build not detonation....a sure way to tell is look at the recording....if the front and rear cylinders are showing timing being pulled at the same time it is erroneous because there is no way the front and rear cylinder can fire at the same time. If you see this and try to remove timing from your map to fix it you'll soon see the problem is the same with the next recording. So to answer your question YES, you can have inappropriate knock retard. If you has (for an example) 8 degrees of timing being pulled by the ECM you should hear pinging...this is detonation...if you see 8 degrees being pulled and no sound it has to be in the build namely the head design.
Icut this short so I hope it answers your question well enough,
Doc

Thanks Doc, appreciate the reply.

I found an interesting item if anyone wants to take the time to go through it all, don't know if this is indeed the exact ion sensing system/process that Harley is using in their bikes,,,,companies will often patent things that they don't actually use or implement, but this was an interesting read none the less.

http://www.freepatentsonline.com/6386183.html

Thanks again.