Tuning for SC on 165 5.7L (long)

[Bruce Plecan]

-----Original Message-----
From: Dave Z <dzug at mail.delanet.com>
To: gmecm at efi332.eng.ohio-state.edu <gmecm at efi332.eng.ohio-state.edu>
Date: Friday, March 19, 1999 10:16 PM
Subject: Tuning for SC on 165 5.7L (long)


I'm talking a SC not a turbo, so the advance
reduction increases (advanced reduced) LINEARLY as RPM increases..
assuming the SC increases boost linearly with RPM. What I'm looking
for here is a guideline for just HOW MUCH to back off... I'm guessing
0-3 degrees as boost goes from 0 to say 5 psi. Oh, the SC manufacturer
states "use the stock chip".. whats with that? I want to be emissions
legal, but skweeze out the power too.

Rules, nope, wanna guess, might look at the buick web site, and over at
syty,
at syty they have graphs with the timing.   Intake air temp plays a huge
role in this, ie you running a MAT?.

the second issue that sticks out is ESC rates. I'm thinking they'll
need to be more aggressive (more reduction faster) as there is more
stress on the components and the stock parts can't take the beating.

The stock ESC is marginal at best in my opinion.  A cylinder has to rattle
for a while for the ESC to catch it.  Care in calibration is the key, and
then using good fuel.

the third issue that stands out to me is Idle power. the SC takes
7-10 HP to just TURN at idle.. how's that going to affect idle and
coast-down performance?

A couple maybe 7-10 seems like alot..
Is this a centrifigal, or positive displacement?.
Coast down I'd imagine about the same, throttle closed is throttle closed.

 might the IAC be able to handle it or need I
adjust the base throttle plate opening so the IAC doesn't sit at 100% all
the time?

????...

the fourth issue is MAF level. my 165 apparently tables up to 208 on
the LV8 scale for spark.. what about 255? I know that IF THERE WERE ROOM I
could re-index the LV8 spark table to include a 13th and 14th column,
and use 2 more steps in resolution but the 16k is FULL, and I'm sure
its not as simple as re-scaling the original 12 columns.. I'll
probably mess something else up. has anyone dealt with the 208
thing or the problem of a FULLLY OCCUPIED 16k space?

Why not got to a 749 ecm and run the syclone code.  Has all the good stuff
already there.  Or use the Holden 808 code which is alot less complicated
then the US, and the figure out how to run a 2 bar MAP with that.  808 has
alot of room for Jumps.

Silly thought here, try tunning the 749 code in your 165......

I'll stop here.
Dave Z - 87 GN 12.74 @ 105 w/1.84 60'