Re: Cam tuning

["nacelp" <nacelp@bright.net>]

> So let me get this straight... in one sentence you say aftermarket
computers are MAP, and GN guys use LT1/LS1 MAFs in place of the MAP system?

He didn't say that.
The buick system just uses a MAP sensor to run a boost indicator (for the
human element, not ecm).
When installing the aftermarket MAP systems they use the *MAF*wiring* for
sending the MAP signal to the new ecm.

> So where does that put me?  I have no MAF, and would rather stay MAP, but
I have no idea how to convert the computer to use a 3-bar MAP.  Is it
possible to just change a "MAP resolution table" in the computer, or is it
all hard coded?

Takes a code change to start.
First, to allow for a correct baro reading.  A coommon gm strategy is for
the ecm to look at the MAP sensor at start up to figure the barometric
conditions.
Then 200 (or 300)  K/Pa is then about 5 volts, so all the calibrations are
off.
To do it 100% right also means doubling the table sizes of going 2 bar, or 3
times for 3 bar.  You don't have to but to get the same resolution as oem
that what you would want to do.  None of the newer ecms/pcms have anything
hard coded into them.  It's all in the eprom, I don't know the finer points
in the flash pcms, but I just understand that the hard coded stuff is for
making them tamper resistant.
Grumpy

>
> Thanks,
>
> Doug R - Black 93Z A4 3.73 - D.B. F-Body Organizer
> Mods: DragRadials,Hooker 1.75" headers,Flowmaster,AS&M CAI
> Mods: 3.73 gears, SLP Torsen, S&S Stage 1 heads, UD pulleys,
> Mods: Chip,EibachSprings,1LEswaybars, AFPR - 13.11@105.5
> *My car: http://daytona.f-body.org/doug
>
> >>> fredericksk@worldnet.att.net 03/20/00 07:48PM >>>
> We use a MAF for all ECM airflow inputs.  There is a 2 bar MAP present,
but
> just to run the silly little boost gauge on the dash.  When people convert
> to DFI or SpeedPro and keep the GM harness with a jumper harness for the
new
> ECM, they generally run the 3 bar MAP signal in the old MAF input signal
> wire.
>
> On most hopped up GNs, the MAF is maxed out after 15 psi of boost or so,
and
> any additional fuel enrichment is 'guessed at' in the PE enrichment
tables.
> A recent upgrade for these ECMs is a 8051 based Translator designed by Bob
> Bailey that allows use of a wider range LT1/LS1 MAF and "translates" its'
> signal.  With an appropriate chip the ECM can read up to 512 GPS, instead
of
> the old 255, allowing better intermediate boost tuning.
>
>
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