Dwell and HEI's

[Scott Linder]

Sandy there are some points the group seems to be missing that you could look
at.
1-there are many different part numbers for the gm modules with many
differences.
2-test the current ramp of the circuit ( we use a lab scope and a inductive low
current probe on the power lead) and observe the actual off to full on current
ramp up ( usually 3.6ms for a stock hei coil)
3-also take a look at the current limit for the coil ( controlled by the
module) usually  5.5 or 6.5 depends on the module.
4-test the aftermarket modules for a different look on the above specs
( some better , some worse).
5-the later hei units have a much faster rise time ( 2.6ms) and a much higher
current limit ( 8-85 amps) for a much stronger ignition.

Jim Linder
the injector " guru"
www.lindertech.com

Sandy wrote:

> Well, sure if the modules are to be driven by standard GM reluctors and use
> a standard GM HEI coil, no problem. But since we (maybe just me) want to
> drive them digitally, and with a totaly different coil, it is something to
> concider. I really don't want the automatic dwell control, as I will have
> the CPU do it for me. I'm getting one tomorrow, and I'll smoke up a module
> and a dual post coil to test it out. Anyone have some starting point for
> duty cycles for testing?
>
> Sandy
>
> At 06:21 PM 2/20/98 +0000, you wrote:
> >Why all the concern about dwell?
> >My understanding:
> >If there is too much, the coil gets hot and maybe burns up.
> >If there is not enough, you get a weak spark.
> >
> >Gm  uses the same module - reluctor coil- Hi voltage coil etc. on
> >both their 4 and 8cyl vehicles.  Over a very wide rpm range.
> >
> >Is anybody out there having a problem with dwell?
> >
> >I suggest not unless they are running a v-12 at very high rpm.
> >
> >Tkhat was one of the problems solved by electronic ignitions that
> >seemed almost impossible to economically solve with mechanical
> >points.
> >
> >Bob McKnight
> >Phx AZ
> >
> >