Ignition Only

[Axel Rietschin]

----- Original Message -----
From: "Ludis Langens" <ludis at cruzers.com>
> Axel Rietschin wrote:
> >
> > A wasted spark DIS doubles the rpm limit of the ignition system since
you
> > have twice the number of coils.
>
> In GM's garden variety DIS, the rpm limit isn't raised.  If anything,
> it's lowered.  It appears that GM sets the dwell time of the DIS coils
> exactly the same as for a coil for a distributor.  In other words, they
> don't start charging up the coil until after the previous cylinder fired.

I'm not familiar with this particular ignition system. On mine, the coil  is
charged during the last 4ms preceding the spark event (subject to a VBAT
compensation). However, I should have stated that DIS has the _potential_ to
double the rpm limit of the ignition system, which is certainly more
accurate.

> The limit might be lowered because GM's DIS coils are smaller than the
> regular coils.  There must have been some negative trade off to make
> them smaller.

Maybe they are smaller because they are used at 1/2 rate compared to a
classic setup?

Regards,
Axel

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