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<DIV><FONT face=Arial size=2>The Iroc at E-town was running MAF, but was sprayed
with a dry 70 shot. It ran a 12.44 that day, and a 12.16 later at another track.
It has a 383 too. Yea the time does not reflect a sprayed 383 but the setup is
very mild and there are lotsa weak drivetrain parts still on it.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>I have a MAP conversion on the car now. I'm at the
stage where yes I am seeing that the VE must drop compared to the stock 350 A4
cal, but only a bit (less VE at idle and less VE by about 9 decimal at 100Kpa
between 3000 and max rpm) since I dialed the engine size and injector const in
given the fuel pressure I run (41). your cam will raise your idle MAP
reading to the area where the stock TPI starts to want lil extra fuel. This will
make the thing idle rich.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>Bruce wrote tuning tips that are definetly the
place to start. tuning 101. </FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>Reading your description, if the o2 falls that low
I would check the fuel pump and pressure first, make sure it is not dropping
off. Hopefully you are not using the old version of winbin, it had a
problem with calculating the injector constant correctly. It is fixed now I
understand and has other enhancements I think I read a while ago. probably with
your mods, the motor wants alot of fuel later in the RPM band compared to the
stock TPI (torque curve moved up with the cam mods) and you need to maybe put a
hump in the PE v/s RPM table. look at the scan results and increase the PE adder
right where the RPM is when the o2 drops, and keep increasing the later entries
until the RPM where the 02 comes back. Its hard to do this without driving the
car and seeing the results ;-)</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>make sure ignition is good (I'm sure you have,
tuning buicks for the number of years you have)</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>First start with a stock a4 (if you have an a4) 350
cal. set the injector constant considering any fuel pressure changes and the
pressure at which the new injectors are rated. get it to idle with IAC counts at
10-20, not 80. the cam will raise the idle MAP reading, I shifted my VE lower
table values rightward (move the lower map values into the next higher cell) so
it wasn't so fat at idle and it worked well to stop the hunting and near
stalling. With cam mods you will see your torque peak higher, therefore the fuel
"hump" in the ve table in a stock cal will be in too low a rpm range, it needs
moved upward in RPM. </FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>The VE is more accurate if you get the injector
const right and the AFR desired is not set wierd to manually compensate ahed of
time. in other words, you should not go straight to adjusting VE entries
in a pig rich or lean car cause you may end up with 40's at WOT before the thing
runs well, and you KNOW the engine is more efficient than that. make sure the
engine size and injector const is right first, tunetips recommends attacking
idle, then cruise first (BLM's), then WOT. If in the coarse of tuning cruise
ranges, you discover that you have to make massive changes in VE, you probably
will be changing the rest of the VE stuff radically as well... depends on the
combo. (and I *only* have actual experience with a 350NA, 350SC, and 350NOS
using MAF, and part of a 350NA MAP (so grain-o-salt)</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>the up down changing of the VE entries will move
the o2 sensor readings up and down DRAMATICALLY ONLY when the o2 is near stoich.
(because the sensor is so not linear).. at 1000 mv, a change of 10 may move the
WOT reading to 0.970's, but another change of 10 may put it at 0.800's. just
gotta change it some, then 'feel the force' to guess how much to change it next
time. It might take a pro 3 attempts to nail 0.870's and an amateur 15 tries.
not too bad, and a bit fun!</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>VE is the "shape" of the motor's efficiency, PE is
the adition of fuel when more serious levels of power are requested. If you did
cam changes, intake mods, exhaust mods, head work then the shape isnt going to
follow a stock 350, and you should work in VE. If the motor is a stock almost
350 with maybe only intake/exh mods, you *can* work directly in PE to make the
WOT o2 sensor reading flat and near 0.880v during a run. (then raise or
lower it until you get the best E.T. cause the stock o2 isnt that acurate) I
think bruce said something similar plenty of times, Tune for power and E.T, (or
economy if thats your gig) not for knock fringe and o2 millivolts.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>geeze I wrote a book. SNIP when replying I
think.</FONT></DIV>
<DIV> </DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A href="mailto:JTesta1966@aol.com"
title=JTesta1966@aol.com>JTesta1966@aol.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A href="mailto:gmecm@diy-efi.org"
title=gmecm@diy-efi.org>gmecm@diy-efi.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, January 18, 2001 5:29
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> 92 Camaro 730 w/healthy
350</DIV>
<DIV><BR></DIV><FONT face=arial,helvetica><FONT size=2>Looking for
tips/suggestions on where to start with fuel mods in this puppy. <BR>A friend
of mine owns the car and converted from a stock 305 to a pretty <BR>healthy
350,,cam, edelbrock heads etc. Had a bucking ~35-3600 RPM which when
<BR>viewed on a scanner shows REAL lean (like .019mV) so I'm pretty sure the
<BR>problem is arising when touching PE but not WOT (car runs well at WOT, but
<BR>I'm sure theres more to be had). My question is kinda along the lines of
<BR>having a 350 program would it be more productive to work in the VE tables,
or <BR>PE tables? If I understand right, the VE tables (high and low) are
similar in <BR>effect to MAF tables on a MAF car. Only thing is the cal he has
now, the VE <BR>tables approach 85% in some areas and I cant imaging the car
is much more <BR>efficiient than that. Does each up/down value have as
dramatic effect as it <BR>seems? <BR><BR>Are there any bins of note on the FTP
site so I can look and see how <BR>different people approach modified airflow
situations? Or does anyone have <BR>experience they'd like to share? Dave Zug?
I remember you having a healthy <BR>camaro at etown last season...care to
share the wealth of knowledge?
<BR><BR>================================================ <BR>Jim (FA) Testa
Type86
on buick.fiendish.net <BR>ASE Cert Master Tech
jtesta1966@aol.com
<BR>L1 Adv Engine Performance
http://www.turbojim.com</FONT>
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