Replaced Dist ign system with SDI system, and computer running very different

[Roger Heflin]

On Sun, 9 Aug 1998, Bruce Plecan wrote:
> From: Roger Heflin <rah at horizon.hit.net>
> Subject: Replaced Dist ign system with SDI system, and computer running very
> different
> 
>   Now with the new ign system, things are
> >running significantly different, so it did change something.
>  Is this a reasonable conclusion given the
> >data?
> Is this a stock cam??..
> 
> If a non-stock cam, then seems like the plug firing at overlap might be
> and emission aid.

Non-stock cam.  The cam I have is a bit larger.

> 
> Amazing results,  were the plugs changed?.   Was this just coils, and
> wires (plus electronics)?.
> 

The plugs only had about 5k on them.  The whole system (ign) was replaced,
including wires.  It went from dist to 1 coil/2 cylinders.  The optispark
(dist) had 110k on it.  On other LT1 cars these things have been wearing
out in much less than that, so it could be the reason why my gas mileage
has continually dropped since the car was new.  


> Wonder if the gm is limiting the coil output somehow on the the oem
> coil or if there was a RFI problem with a good coil
> 

I am going to have to see what the gas mileage.  Does anyone know if 
having the timing changed would cause this kind of differences in fuel
usage?   The car sounds the same, and I did some tests, and power is
pretty close to the same.

			Roger