Craig: Inductive delay setting with MSD?

[John at J&S]

Craig: I'm working with a Porsche guy using your system. Harv does his tuning.

It's trggered from an MSD flying magnet crank trigger, and driving an MSD 7.

Am I correct in assuming that the inductive delay in the Global Parameters window is to compensate for the slow turn off of an inductive discharge ignition, and not the delay of a magnetic pickup?

Since he is running an MSD, shouldn't the delay be changed from 96 usec to 5 usec? If it's not changed, won't they have more timing up top than they think they have?

If we add our knock controller in series, we just add its delay to whatever number the tuner has for inductive delay, right? So if the tuner wants to keep the value at 96 usec, and our system adds another 50 usec, enter 146 usec?

I think Motec has a similar setting, and they call it ignition delay. That term seems less confusing, and easier to explain to the tuner.

 

[bobc455]

Pretty sure that delay is for the injectors, not the ignition.

-Bob Cunningham
bobc@gnttype.org

 

[Craig Smith]

This setting is used to compensate for any fixed delay within the ignition system, regardless of its source. I believe the ignition delay setting that Motec uses is the same thing as the inductive delay setting in our software.

As far as changing this value from 96 uS to 5 uS, I have never verified or heard from anyone else that leaving it at 96 has caused any timing error with an MSD ignition system. I personally have no interest in grabbing a timing light and hovering over an engine running at 7000 RPM.

This setting is basically a fudge factor to account for delays in the ignition system no matter what is causing them. If you have your timing right on at 2000 RPM but the timing seems to retard itself at higher RPM, increase the value. If the timing advances with RPM, then lower the value.

Hope this helps - let me know.