Dwell control time ls2 coils

[Roger1436215387]

Does anyone have the correct ms dwell control time for the ls2 coils? i am having trouble starting my rotary i'm thinking this could be a problem. Its also really hard to perform the trigger setup as it jumps around too much.

so far i have found 6-9v is 5ms then from 9 to 15v it drops progressivly to 3ms

[Simon]

That will be enough to get it running. The LS coils can take more dwell than most and at 14volts could be 4ms happily.

Is the RPM reading nice and stable?

[Brad Hansen]

Roger,

Myself and another friend both run g4 xtreme ECUS with the d585 coils (myself on an extend port s6 13b-rew; and him on a semi-pp 20b) we both have 3ms across the entire map for dwell time.  

Can you go into more detail about your troubles getting your engine to fire? Maybe post up your map?

brad.

[Roger1436215387]

While cranking i noticed the rpm signal was dropping in and out, and when i did get it to run it would pop and back fire from time to time.

Following some info from Simon i reduced my trigger arming voltage and hey presto she fires up much better. i have set my dwell to 4ms. while cranking and using the standard dwell ms i found the ls2 coils were prematurely firing causing problems. from some research there is an internal function on the ls2 coils that discharge once the the ms excedes 8ms

Brad, do you have an ignition map you recommend as a starting point? so far i started with the start up map and just went up and down trying to get a nice start and revving while stationary. with the trigger arming issue i found it very difficult to do the trigger calibration as it was bouncing around too much to be accurate so i got it as close as possible, and once started it still was very difficult to set up. that's my next job now the thing fires up and with a better trigger arming threshold.

roger.

[Brad Hansen]

roger,

i started by setting the trigger calibration with no fuel just cranking; once i was happy with that i played around til it would start and then found what sort of timing it liked for idle, mines a streetport and idles around 1000rpm and 50-60kPa MAP.  for these cells it liked about 21 deg, yours may be different however, i've seen all the way from 10-20+ its just a matter of messing about.  my timing map is basically an adaption of a pineapple racing streetport timing map that i found online; so far only tuned up to 4500 9psi.

brad.

[Stevieturbo]

The LS2 coils with the heat sink discharge at about 5.5-6ms

But there really is no need or point to run them any higher than 5ms. Even about 90% of cars wont even need that much with the normal older style coils. They are all very powerful units, so keep the dwell well below the automatic discharge time.