Re: EPROM tuning head start

[Shannen Durphey <shannen@grolen.com>]

WEG1192@aol.com wrote:
> 
> Ok, so what you are saying is that a perfect tune depends on having perfect
> weather.  And that at any other time the tune is off and the BLM is depended
> on to keep the motor running at stoich? Also, earlier I saw that the ESC
> should not be used as a tuning aid but that is exactly what happens if you
> use knock retard as an indicator that the timing is advanced a little too
> far. Since the ESC module is what tells the ECM that knock is occurring, you
> are using it as a tuning aid.
Not as a tuning aid?  I thought it was not supposed to be used as a
tuning crutch.
> 
> Another thing, I saw recently where it was recommended to use just a DVM and
> nothing else to tune with. Without a scanner or Diacom, how will you know the
> BLM, the knock counts, etc.? I guess I'm just either too ignorant of what's
> really going on or my idea of a good tune and yours is relative. 
The DVOM thing is like making kids learn to do math with pencil and
paper before allowing them to use a calculator.  You have a much
better appreciation for what is going on if you learn to tune without
the scantool.  Some of us learned auto computer stuff when scantools
were a luxury.
I mean, I
> thought GM tuned engines to reduce combustion temps at cruise to reduce NOx
> emissions, but maybe you are tuning for different criteria like maximum
> acceleration. If you define a perfect tune by the summer temperature outside,
> then during the winter, the engine is not going to be in perfect tune. 
Well, consider the amount of variables you're working with.  Humidity,
air density, fuel, ambient air temp, different driving styles,....
There is no "one size fits all" tune.  The factory stuff is the
closest you'll find to that.  The magazine chips are the next best
thing.  That's the whole reason to do your own, because you'll have a
one size fits one calibration.  And we need to make sure we're talking
about the same thing here.  Just because the ecm is making up for
variables doesn't mean you don't have a good calibration.  You want
the calibration to be the most right for your use.  At this point, you
have got an imagined picture of what a perfect tune should be.  You
need to get some equipment, and start trying to convince the ecm that
your idea is right.  You'll eventually realize what can/can't be done
with a calibration, or walk away from this list frustrated with the
members who are telling you that it doesn't work that way.

All I
> want is a smooth running engine regardless of which 350 motor I put it on and
> during any season. I need a 350 chip that is versatile, not restricted to
> just one exact car. 
Woah!!!!  Even the factory can't do that, and they put the same engine
in millions of vehicles!  You should see how many calibrations there
are for....  Well, here's an example. 1987, 5.7 liter V8, VIN code
"K".  Same engine is used in pickups and vans.  There are 81
calibrations for that engine!!!!! Add in the # of cals from 88, and
the total rises to 146. Totl increases every year, too.  Remember that
the factory has way more time and resources to make a "generic" chip
than you do.  And it looks like they eventually figure out how.  Move
up to 91, same engine, same ECM, and there are only 27 different
calibrations.  5 years, millions of the same engine produced, millions
of customers reporting on driveability, thousands of hours invested in
making cals., and there are "only" 27 different ones available.  Does
this put your goal into perspective?  And if you want to look at the
2.8 and 3.1 liter V6's, the numbers go waaaay up.

I think I am talking apples and you oranges. I'm not
> looking for a chip to have the absolute fastest 1/4 mile times, and I think I
> have fallen into a hornets nest full of drag racing hornets. 
Drag racing?  My 57 pickup gets driven about 3 or 4 times each year,
to shows or just for fun.  NO racing.  Each time I drive it, I bring
down another chip.  I try to dedicate at least one day with the laptop
and burner to the truck each summer.  Yes the racers want to get the
most from their cal, but not everyone who wants the most is a racer.

>Maybe a stock
> 350 GM chip is just fine for my AMC 360 stock engine. That's all I was really
> trying to find out anyway.
Ok, I think I see what's happening.  You can do an alright job of
turning wrenches, yes?  You can find your way around the engine
compartment well enough?  How much work have you put into the Jeep? 
Do you work on it for fun?  Do you enjoy making changes and seeing the
results?  Do you like to know an hour of work made a difference? 
That's what chip tuning is like, but without the busted knuckles and
greasy clothes.  Some of us enjoy tuning to the Nth degree.  Why? 
Because we can.  Do you have to go that far?  No.  But there are still
reasons to tune your own chip.

You will have to start with a stock calibration.  There are different
ones available.  If you try several of them, you will be able to
successfully answer your own question, "Will a stock 350 cal. work
with my 360".  You may find a chip that has an acceptable spark curve,
doesn't generate excessive emissions, and feels ok to drive.  If
you're happy with it, then you're done.  I'll bet that you won't be
happy with what you find.  After all, you weren't happy with the stock
AMC setup...
So, if you try enough stock calibration to find one you like, then you
find yourself saying "it runs ok, but...", it's time to start tuning.  

You can buy an inexpensive scantool at Sears.  Ask for one for your
birthday, get some friends to pitch in, whatever.  If you're comparing
stock calibrations, it's a good idea to have one of these anyway.  You
can get an eprom burner and eraser for less than a set of 32" tires. 
With these tools, you're on your way to fixing the "It runs ok,
but..." condition.  There's a ton of info in the archives and on the
list, it's very confusing without something to reference it to.  Don't
panic. You don't have to know everything about efi to install a bunch
of parts on your truck and see what happens.  The learning comes
later, when you set out to make it run the way you want.
Shannen
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