compression ratio, '88 5kcstq (motor)

[Orin Eman]

> If I run a J&S Safeguard, would I still need or want the code 
> tweaked?

You'll probably need 12 to 15 degrees of retard.  can the J&S
do that?

> Or rather a bigger question, is there any need or advantage to 
> running a J&S Safeguard with a modified (okay, SJM) chip on an 
> '88 5kcstq?  How about if I'm running 8.5:1 c/r?

There is an advantage.  The stock system is tuned to a specific
frequency of knock.  If you change the cyl size, that frequency
will change so the stock system may not detect knock as well.

> Is the stock knock sensing ignition any comparison to the J&S, 
> which is supposed to be really fast, and cylinder-specific.

The stock system is buggy, isn't really cylinder specific
and is slow to recover from knock.  The MC-2 (MAC14 dual knock
sensor) is a lot better in this respect.  If you raise the compression
in an MC-1, using the MC-2 timing table of an MC-1/MC-2 hybrid
might be a good idea.  Note that there are areas in the MC-1 table
where the MC-1 in stock form doesn't run and have default values.
You may have to fill in these areas (low rpm, boost).

So in summary, I think the J&S would be a good idea.

> Todd Phenneger <tquattroguy at yahoo.com> wrote:
> >
> > Heya,
> > 
> >   I'm running 8.8:1 at 9psi with no problems.  I will run more but
> > not till I get an IC in there.  On hot days it will ping at any
> > thing over 9psi.  Pulls GREAT down low and really helps turbo
> > spool up. 

IMO, if you get audible knock, you are probably doing damage.
You should never hear knock if the knock sensor is working properly.

Orin.