Waste Spark Coils

Jurgen Hartwig jhartwig at midsouth.rr.com
Fri Feb 23 16:21:41 GMT 2001


> I am replacing a Stock EFI with an Aftermarket EFI.  The Original car
came
> with a single coil and distributor,  but the computer timed the spark.
I
> assume the ECU had the "igniter" in computer.  There was no electronic
> ignition module on the car.
>

Hi Paul, let me weigh in with my amatuer opinion.  First, what aftermarket
EFI system are you using?  An ignition module, especially on distributor
systems, can be hidden inside or attached to the distributor.  Something
needs to fire the coil.


> The New Ignition can not work with a distributor.  It needs to be a
> sequential spark of Waste Spark system.  I am going to start with Wasted
> spark so I will not need to have a cam position sensor.
>

Sounds good.  I am going with waste spark, as well.  It is clean and
simple, especially with an aftermarket setup.

> I do not understand the need for "smart" igniters.  Is this needed to
> interface with an engine management system?
>

I believe the "smart" igniters control the dwell.  My setup, Wolf 3D, has
software selectable dwell setting, so I guess I don't need a "smart"
igniter.

>From what I've seen, which isn't saying much :), the GM & Ford waste spark
coils are usually driven by a "module."  This module is driven by the
engine's sensors, so these modules would be difficult to implement with
the aftermarket engine management setup.  So, what some guys have done is
use a GM/Ford waste spark coil with a Bosch igniter.  The Bosch igniter is
a totally separate piece.  The Bosch igniter can be used with the
aftermarket systems, and this is what you are after.  Your alternative is
the RX-7 coils, which is my choice.  However, in retrospect I like the
fact you can easily and cheaply replace a GM coil.  A new RX-7 coil is
over $125.  Used are cheap.

So, depending on what engine management you have, you will need the
following:

1) Waste spark coils
2) The appropriate spark plug wires
3) Igniters which will work with the coils, and more importantly, be
compatible with your aftermarket ECU

The only other hardware necessary is the proper wiring (i.e. ground, 12V
from ignition, and trigger lead).

Now, I hope that makes things clearer.  Anybody have recommendations for
quality spark plug wires?  I was leaning towards Magnecor.  Who else might
sell bare wire and connectors?

Jay

PS> Bob Wooten, you may deduct hobby expenses, but I believe those expense
must be business- related.  If you use your car to promote your business,
you can deduct expenses, but you need to start showing a profit in a
certain time period.

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