DFI Revisited

[Howard Chu]

> From: Kenny Bauman <kennybauman at yahoo.com>
> Subject: RE: DFI Revisited
>
> Howard,
>
> Are you referring to the Nippon Denso coil near plug
> technology that is used by Chevy. (one per cylinder)

Yes, exactly. In fact, I ordered "GM LS1" ignition coils
and the coils themselves have NipponDenso stamped in their
plastic housings.

> If so those coils are not smart. the dwell is
> controlled by the signal going high (start dwell) when
> the signal goes low the field collapses and the coil
> fires. Length of signal is dwell time.

> Optimum dwell time is 5.5 milliseconds.

Thanks, that's what I thought. What I was afraid of too.

> - --- Brian L Massey <blocklm at juno.com> wrote:
> >
> > On Fri, 26 Oct 2001 08:23:08 -0700 (PDT) Kenny
> > Bauman
> > <kennybauman at yahoo.com> writes:
> > > Are you referring to the Nippon Denso coil near
> > plug
> > > technology that is used by Chevy. (one per
> > cylinder)
> >
> > > Optimum dwell time is 5.5 milliseconds.

> Nope, it's second hand and should be taken as such.
> Got it from Tracy Crook at www.rotaryaviation.com

I can't reach the site at the moment, but I'll check again later.

> He makes a simple ECM that can use these coils.

Sounds pretty convincing to me. It's also fairly close to the published
Delphi literature, which gives the charge time as 4.4ms and the spark
duration as 1.9ms. (Actually, that spark duration seems a little long, but
then again I don't understand their standard test conditions. This is
discharging through an 800V Zener diode?)

  -- Howard Chu
  Chief Architect, Symas Corp.       Director, Highland Sun
  http://www.symas.com               http://highlandsun.com/hyc

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