What is funny to me over all this is the way MM behaved way back at the start (3-4 yrs ago) . All he needed to do was say "I'm not sure how the table works but if you do this ...... it works " . Instead he got as much mileage as possible out of it when he really didn't understand how the table worked himself. Typical of his behaviour throughout his time here .
And MM - if you are reading this by chance.......... I'm laughing at your inability to respond to this .

 

wow

 

I would recommend higher dwell settings in the high rpm range

 

and also reading this: http://www.dtec.net.au/Ignition%20Co...alibration.htm

 

good article---lately i have been watching the systems voltage as controlled by the pcm. There is a certain point in which the pcm will supply over 14 volts to the system. I have been able to identify that this occurs at a certain fuel injector duty cycle, but never related it to the coil. Perhaps there is a correlation? IDK for sure.
I am running the oem dwell map with msd 8247 coils. The coils require a 3ms dwell. They have been performing well--no problem with start up hot or cold, no misfires. But after seeing this information--i do wonder if they need a little bump in the higher rpms.

 

as usual, that makes no sense because the coils have voltage compensation, further the OE system typically outputs less than 3 deg dwell above 4000 rpm

I am in the process of installing a set of the Mercury/Motronic IGN-1A coils

 

didnt say the increased voltage was for the coils. I just noticed it was there. What is the voltage compensation for the coils then? The table goes up to 15-16 volts. God forbid.
The mercury coils are suppose to not require much dwell and should do great with the oem dwell settings. Making your own harness?

 

It's amazing what information comes out when debate/discussion isn't stopped out before it can flourish.

 

You say it's a great article, but apparently you didn't read it. The coil is an energy storage device. The higher the voltage the less time it needs to reach saturation and vice versa.

This is why the discussion flourishes ...

 

i am not making myself clear? if my voltage to the coil is increased to 14 volts--then my dwell will not need to as long as it does at 13 volts. That is what I am saying.
I dont know that the coils are actually seeing 14 volts. I do know at certain points that much voltage is in the system. I would need to see what voltage is actually being delivered to the coil before i change any dwell settings? Thats my point. Or do you just increase the dwell settings in the cobb table without worrying about what voltage is being delivered? That doesnt make sense to me...

 

:facepalm:

 

OD,

I believe the table is voltage based so it isn't a matter of adjusting your values based on nominal voltage from your battery.

I think your question is more around whether the ignition circuit needs more reference voltage to deliver the right dwell at higher RPMs.

I've noticed the voltage jump myself, but have never correlated it to anything other than charging the battery. I'm pretty sure I saw it the other night in my driveway while idling.

 

OD
The ecu knows what voltage is in the system . The dwell table references voltage and rpm so the ecu looks up how much dwell it needs at that voltage and rpm according to what the lookup table says .

 

Unless you are continuously exceeding 10,000 rpm or trying to make your D585 coils last a lifetime there is no need to run less than 5.4 mS anywere @ 12 volts or relative equivalency at other voltages

One of the reasons the normal LS2 coil doesn't need as high of dwell settings is because it's output is less than the D585 coil. It is not really recommended for FI applications, though is probably adequate for Na or lower boost settings.

 

to get it clear for a noob .. is it safe, to still multiply the dwell table with 1.45 for the BHR coils ?
Especially at the lower rpm range ?

because i have a maß with that setting, but i'm not sure if it will be safe to the engine and coils itself.

thanks for the answer

br,
EdFred

 

i know I am a pita sometimes fellows. I appreciate yall trying to explain things to me.
The oem dwell table didnt make sense to me at all. Oltmans does.
Since my coils needs 3ms-- i need to figure what percentage to adjust the higher rpm cells.

this may be posted somewhere else IDK but for those interested (maybe Brettus?)here is a factory dwell map ( from a SUV) using the d585 coils:http://i305.photobucket.com/albums/n...5CoilDwell.jpg

 

It was posted by me last year two pages back in this thread

Oltmann posted an Excel file on the previous page that does the conversion for you

You are going to use up all my facepalms again ...

 

In the case of the std LS2 coil, or any coil, you can't just go changing dwell blindly without considering the whole picture. As dwell is increased so is the coil amp draw.

In the case of the std LS2 coil you can see in this link

https://picasaweb.google.com/m/zoom?...portHeight=268

that the coil reaches saturation at 4 mS dwell, but at this setting the current draw on the coil power supply wire is close to 12 Amps. Even at 3 mS it is around 8.5 Amps which is pushing it on the OE wiring harness. If you exceed the current capability of the harness it will melt down and the end result would likely not be good.


.

 

my coils draw 11 amps at 3 ms and the harness is fine.
However that is a good point. evaluate the entire system--not just one component.
I do wonder why mazda reduces the dwell on the oem table in the higher rpms? There has to be a good reason.

 

Time?

 

I would have said ... heat .

 

That too

For sure with the OEM coils........

 

Lol--yea--so they knew the coils were not up to par?
Surprise!

 

I am waiting on the next bulk boat load of salt to arrive so forgive me if I don't jump on your credible info source bandwagon ...