OEM Dwell map plotted against voltage (based from the formulas in the ECU to get dwell): Oscilloscope trace of Z32 Dwell: Here is a mj output test at 14V on these individual coils: Here is a mj output test on the D585 coil: Here are the maps with the RPM points map adjusted so dwell is equal. R8 Dwell Time Map, corrected per RPM, Percentages to input into Nistune are on the left: R8 Coil RPM Map, Percentages to input into Nistune are on the top: ------------------------------------------------------------------------------------------------------------------------------------------------- LS D585 Dwell Time Map, corrected per RPM, Percentages to input into Nistune are on the left: LS D585 Coil RPM Map, Percentages to input into Nistune are on the top:
Those dwell times for the D585's even at the lower voltages are very long. How were those dwell times derived? E
For those like me that had no clue. Thanks heaps for the post. http://www.dtec.net.au/Ignition Coil Dwell Calibration.htm
well many are just going by a global percentage change and it is working for them, I went a step further and using the OEM D585 coil map adjusted further. Here is what it looks like when that global change is done: I can go further to adjust it to be just like factory but the coil doesn't self discharge until after 5-6ms+ and most are running a global change which seems to be working. The actual working range is 10V - 16V and the Z32 barely runs at 12V, so we look at a range from 12V - 14.6V. The mapping I posted has them running at around 4.10 ms the one most use after the conversion runs them at 4.70 ms. Here is OEM D585 dwell map... I can copy the map if needed but like I said many guys running 5.0 ms, I went lower.
Here is what it looks like when that global change is done, what many guys are told to use: OEM D585 Map: Just got the mapping close to OEM with the Nissan OEM ECU limitations:
there doesnt really seem to be that much difference between stock vs the vw coils . is it really worth the hassle?.,, comparing stock of 89mj to the vw 105mj is there going to any difference vs spark blowout ? id be interested to see output levels at 12v have you compared a stock system running a hks DLI ? arnt the vw coils known for having a short life?
Earlier and OEM D585's seem to like the longer dwell times. However, many of them are self-discharging at as low as 4.5 Ms and dwell times now are specified at 4.0Ms @ 13/14v these days as a safe figure. Additionally, the self discharging is random and can have some pretty nasty effects. grenaded engine sis a fairly common one!!! E
Ahaa, ok you noticed something here. The OEM coil is driven by the ECU through the RPM range at 1.9ms to 2.10ms, now look at the chart and see the output there. The VW coil is driven at 2.80ms - 3.0ms. The VW plug also has longer spark duration even if driven at 2.0ms! They have been working good on 2000+whp Audi R8s. Shops have sold R8 coil conversion kits for the Z32 without even knowing basics on the OEM Spark tables or how they will work on the car at the 2.0ms dwell from the factory settings! The VW coil starts to saturate shortly after 3.0ms, say 3.5ms. their sweet spot is 2.75ms - 2.85ms. The VW R8 coils have been improved for longevity but recently they even revised it after a few shops complained, now the revision "F" is the latest red R8 coil to get. The VW R8 coil output is higher than the OEM coil with the HKS amplifier. I believe it jumped to 71mJ output with amplifier. The LS coil and R8 VW coils are superior to the OEM coil but the OEM coil is no crappy coil either like some thought. I had set dwell on my OEM coils to 2.5ms for a few years and no issues. Not too sure why nissan severely under drove the OEM coils but then again the car was 300HP at the crank from the factory with low boost.
