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[joe_lyons50023]

I know there are people that understand this better than I do but could the ION sensing voltage be used to tune ignition timing?  I know the "BEST" place to have your max pressure is 17* ATDC but since the number of teeth only allow 11.25 increments it would have to a pretty close thing.  I do believe that for the rear cylinder that would be Tooth 6-7 and for the front be tooth 42-43.  Also when is the ION voltage polled, all of the time or just when on compression and power stoke? Any input is greatly appreciated.

[hrdtail78]

There is plenty of info out there on ION sensing.  There is also some good info on using it to read pressures.  From what I have seen.  The harley (and others) need more to get it done.   .....and at least a 360 tone wheel.

[joe_lyons50023]

Where did you read the stuff about harleys?  In a perfect world having many more notches on the flywheel would help but I believe that 11.25°-22.50° is close, what else was needed? I tried reading though some of the ion sensing stuff but most of it was over my head.  Nothing said that stuck out to me that a higher voltage or a lower voltage meant anything.

[joe_lyons50023]

I also think that this might be out of the question for monitoring this through a program because of the slow data transfer rates. But I don't know if the capability is there for the ecm Internally.  Or possibly and outside monitor that has a high transfer rate of Info to monitor crank pulses, and ion voltage but be able to filter out only the crank teeth that you wanted to view with the correlating ion voltage.  Any electronic wizards think this is possible?

[Buckeye_Tuning]

No, an ION sensing system cannot go fine enough like a pure transducer system would.  Think about false knock... that is just 'wind' inside of a cylinder blowing the spark around, in some instances.  A transducer, OTOH, reads Pressure.

[joe_lyons50023]

Are you saying that ion pressure monitoring wouldn't work for Harleys or in general because there are quite a few cars that have ion sensing units for closed loop timing.

[FLTRI]

For whatever reason(s) the Delphi ION sensing knock control is somewhat forgiving considering the modeling used to develop it.

The problem that I see folks having dealing with knock is they read where the knock occurred and remove timing from that cell(s).

The fact is, when a knock is identified by the ECM it reacts.
There is a build up that leads up to a knock and that takes time.
So if a 4 deg knock retard was identified @ 3250 rpms @ 80 kpa I start removing timing sometimes 500 rpms ahead of the event and sometimes starting at earlier KPA.
Ie: 4 deg knock detected, so take out 1-2 degs 250 rpm and sometimes 20 KPA ahead of the report if it is a high compression build.
This will move to preclude the build up of the event. This also is why some find tuning knock out such a challenge...they are adjusting timing after it's too late.
Bob

[Buckeye_Tuning]

Bob is on the money for tuning timing.  I have been taught to do the same.

Joe, I do not think at present we can use this at all....  no good tools to let us at data.  Plus, I figure with coil on plug, cars have a better chance of this somewhat working better.  I'm quite sure you have witnessed false knock on our ION system, Joe.  I am also sure cars get this.  So... software would help one determine whats really happening, and maybe cars guys have the tools...  but we don't as of now.

I won't have the money for years and years and years...  but when I turn 65, I would like to have the DJ torque arm set up, like BVBob, Russel and Jason have.  I would also like to have a set of heads with transducers in them.  MAX torque AND no ping would make some nice timing maps, heh!

[FLTRI]

When you turn 65 I will sell you mine.
And my 4 gas analyzer to boot!
And my Mustang emissions dyno.
By then in will be too old to use them! Lol
Bob
Oh, and my CDS 24 channel d/a system configured to work on Dynojet 250i.

[hrdtail78]

Problem with whatever you want to use is we will still need to know crank position in a better fashion that we do now.  Or maybe the proper term is resolution.  At least 360 would be doable and 720 would be ideal.

[FLTRI]

Problem with whatever you want to use is we will still need to know crank position in a better fashion that we do now.  Or maybe the proper term is resolution.  At least 360 would be doable and 720 would be ideal.

yep...works pretty good for all the variables...and a whole ton better than anything else on the market for STREET use. It's all about rideablility on the street. The max power is useful for the numbers but seldom used on the street by compared to all other areas of operation. Race vehicles run almost 100% of the time @ 100kpa.
Bob