Coil Dwell Settings with ProTuner & AccessPort
07-19-2009, 12:46 AM
#1
Hmmmmmm.........
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Coil Dwell Settings with ProTuner & AccessPort
OK Brettus started a thread in Ignition Timing that spawned a crap fest on Dwell settings. I was actually starting to get into the whole discussion but it was distracting the original threads intention.
I thought I would start a thread to continue the dwell discussion.
So to start with,
And then
So now we believe/understand that the dwell table shows % of crank rotation time I am curious what people are running with what coil setups.
We have 3 common setups that I am aware of OEM, LS2 (BHR) and Bosch HEC 715 (MazSport). I am curious what people are runnning.
Kane posted some in the Timing thread:
EDIT: Updated this to a more recent map that is working much better
HEC715
I thought I would start a thread to continue the dwell discussion.
So to start with,
Kane,
I work with Ignition computers as I'm involved in conversion of Diesel engines in to NGV (Natural Gas). In the software I use to program the stand alone ignition computer, the dwell value can be adjusted in - % percentage. Basically 100% would mean dwell will be same duration as the spark duration. 110% means the coil will take 10% longer to charge and then provide spark with the same duration.
Looking at my SPT dwell map, could the map be battery voltage vs % time of dwell? That would mean 1208 might be 120.8% and 395 might be 39.5% of spark duration.
I work with Ignition computers as I'm involved in conversion of Diesel engines in to NGV (Natural Gas). In the software I use to program the stand alone ignition computer, the dwell value can be adjusted in - % percentage. Basically 100% would mean dwell will be same duration as the spark duration. 110% means the coil will take 10% longer to charge and then provide spark with the same duration.
Looking at my SPT dwell map, could the map be battery voltage vs % time of dwell? That would mean 1208 might be 120.8% and 395 might be 39.5% of spark duration.
Wow. There it is. (EDIT - Sorta. Its not a direct % of available spark time, but crank rotation time.)
So after months of speculating and even erroneous input from people who are actively involved in RX-8 calibration testing and development, it took a professional ignition calibrator's input to figure out what I managed to figure out in my garage in 10 minutes with a cheap scope meter.
I'm not picking on you, a_ahlan. You are just sharing what you know.
But its just sad that all of the whiners in this thread just couldn't be bothered with the R&D, just because they knew someone had already figured it out.
It was more worthwhile to complain about it.
So after months of speculating and even erroneous input from people who are actively involved in RX-8 calibration testing and development, it took a professional ignition calibrator's input to figure out what I managed to figure out in my garage in 10 minutes with a cheap scope meter.
I'm not picking on you, a_ahlan. You are just sharing what you know.
But its just sad that all of the whiners in this thread just couldn't be bothered with the R&D, just because they knew someone had already figured it out.
It was more worthwhile to complain about it.
We have 3 common setups that I am aware of OEM, LS2 (BHR) and Bosch HEC 715 (MazSport). I am curious what people are runnning.
Kane posted some in the Timing thread:
EDIT: Updated this to a more recent map that is working much better
HEC715
Last edited by auzoom; 08-28-2009 at 07:50 AM.
07-19-2009, 01:29 AM
#2
I deleted the dwell thread I started because there was too much misleading info in it .
From that thread I learned a few little titbits but still do not understand how the mazda map relates to the actual dwell at the coils .
I did get this gem of info from someone though :
It is so unbelievably simple that a trained monkey could work it out . However no-one apart from MM ever did , so maybe you actually need to be one
From that thread I learned a few little titbits but still do not understand how the mazda map relates to the actual dwell at the coils .
I did get this gem of info from someone though :
It is so unbelievably simple that a trained monkey could work it out . However no-one apart from MM ever did , so maybe you actually need to be one
07-19-2009, 02:32 AM
#4
cool thread. lots of questions.
you're not that far from stock with the HEC. you have a shorter charge time towards the top, right?
what effect does charge time have on performance?
is a longer charge time in the later rpms better?
is a longer charge time tougher on coils?
the bhr coils have a long charge towards the top, right?
can dwell be tuned for performance without changing coils?
you're not that far from stock with the HEC. you have a shorter charge time towards the top, right?
what effect does charge time have on performance?
is a longer charge time in the later rpms better?
is a longer charge time tougher on coils?
the bhr coils have a long charge towards the top, right?
can dwell be tuned for performance without changing coils?
07-19-2009, 06:52 AM
#5
Hmmmmmm.........
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I deleted the dwell thread I started because there was too much misleading info in it .
From that thread I learned a few little titbits but still do not understand how the mazda map relates to the actual dwell at the coils .
I did get this gem of info from someone though :
It is so unbelievably simple that a trained monkey could work it out . However no-one apart from MM ever did , so maybe you actually need to be one
From that thread I learned a few little titbits but still do not understand how the mazda map relates to the actual dwell at the coils .
I did get this gem of info from someone though :
It is so unbelievably simple that a trained monkey could work it out . However no-one apart from MM ever did , so maybe you actually need to be one
It has its moments!
I will start by saying I am the last person to be answering this but my first thoughts are that its like a camera flash, it needs to charge long enough to have sufficient power to light the bulb. If the charge time isn't long enough, the spark may not be strong enough to light the fuel. Not sure what happens if you charge to long.
This is one of the things I am trying to figure out...
Good question, not sure.
In comparison to the OEM ones in NA form yeah. Not sure how they would be configured in FI form. I am making the assumption here that the same coil should be different NA v FI.
No idea about performance but regardless of the coil on the car you can change the dwell settings.
Cheers
Andrew
07-20-2009, 07:17 AM
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cool thread. lots of questions.
you're not that far from stock with the HEC. you have a shorter charge time towards the top, right?
what effect does charge time have on performance?
is a longer charge time in the later rpms better?
is a longer charge time tougher on coils?
the bhr coils have a long charge towards the top, right?
can dwell be tuned for performance without changing coils?
you're not that far from stock with the HEC. you have a shorter charge time towards the top, right?
what effect does charge time have on performance?
is a longer charge time in the later rpms better?
is a longer charge time tougher on coils?
the bhr coils have a long charge towards the top, right?
can dwell be tuned for performance without changing coils?
To establish a basis, my understanding is dwell is the overall charge time where the coil generates a magnetic field. When this field collapses it creates a discharge which is what lights the electrode on the spark plug. Someone stop me if I'm off base.
Different ignition coils have different dwell operational ranges. It mostly depends on the vehicle application. The longer the dwell the larger the charge. There are extremes on both sides.
If a coil isn't given enough dwell time it's not able to form a strong enough magnetic field which results in a weak spark. With this you're looking at incomplete or no combustion at all. On the flip side, there is a point where excessive charging doesn't result in a more powerful field and instead it's turned into heat energy.
Excessive charging will overheat the coils and shorten their life. Also you only have so much crank rotation time before you have to fire off the spark plug.
Longer dwell times only become an issue in the upper RPM band because as the motor spins faster you have less time to charge the coil.
Spark discharge needs to be its strongest at the torque peak because this is where combustion chamber pressures will be at their highest.
Dwell can be adjusted without changing the coils, however it will depend on the design of the coils in question as to what dwell settings are effective.
07-20-2009, 07:27 AM
#8
The coil properties should not be any different from NA to FI - they should be what the coil wants / needs to make maximum energy without burning out.
Having said that - I have confirmed the dwell test in the TSM - and OD got me this info... so it looks like I am right for wrong reasons maybe... but I really don't care about the why - only that it works.
And again BHR needs 5ms of dwell.
This jives with the Service Manual testing procedures. 3.3/5 or 3.7/5 = 135 to 150% increase in dwell..... I don't know why this is so mysterious.
Having said that - I have confirmed the dwell test in the TSM - and OD got me this info... so it looks like I am right for wrong reasons maybe... but I really don't care about the why - only that it works.
Originally Posted by olddragger
Hey Dude--dont know if you need this or not but here it is
Volts Dwell
8 9.5
9 7.7
10 5.9
11 4.9
12 4.2
13 3.7
14 3.3
15 2.9
this is oem of course
Denny /olddragger
Volts Dwell
8 9.5
9 7.7
10 5.9
11 4.9
12 4.2
13 3.7
14 3.3
15 2.9
this is oem of course
Denny /olddragger
This jives with the Service Manual testing procedures. 3.3/5 or 3.7/5 = 135 to 150% increase in dwell..... I don't know why this is so mysterious.
07-20-2009, 10:48 PM
#18
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On stock coils? I have been told, yes. You will burn them out and there is no reason to do it anyway.
On Yukons? Again, this is the core of the whole issue, but Yukons are fine out to 8ms, I think, where they have an internal quench or cutoff.
On Yukons? Again, this is the core of the whole issue, but Yukons are fine out to 8ms, I think, where they have an internal quench or cutoff.
Last edited by carbonRX8; 07-20-2009 at 10:53 PM.
07-20-2009, 11:47 PM
#21
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yup, so easy that I updated my dwell settings yesterday.
07-20-2009, 11:52 PM
#24
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if you're not cheating, you're not trying hard enough.
07-20-2009, 11:58 PM
#25
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Like I said. Once I can confirm what I learned from MM, I will be happy to share. Stick it to the man, so to speak. Until then, all I could say would be hearsay.
Besides, the whole drama is entertaining. Like "Days of our Lives" 20 years later I fully expect Bo and Hope to be almost getting married. And Sammy or Stephano trying to kill everyone.