RE: Cam tuning

["the Fredericks" <fredericksk@worldnet.att.net>]

Sounds like I've been adequately explained.  :-)  I believe there's also a
version of the Translator available for 93-up F-bodies; at least the last
one I put on for a guy had instructions for use on them.  The earlier TPI
F-bodies would seem to be out in the cold, although didn't the late TPI MAF
systems (88-89?) use a frequency based MAF as well?  If so, the Translator
could be made to work with them easily.

The other neat thing this system does is allow slight fuel adjustments by
biasing the transfer function of it's signal; it has switches to add or
subtract fuel.  It also allows timing adjustments by intercepting the ESC
signal and retarding/advancing it.  These strategies are fairly limited
though; no substitute for proper programming IMO.  I plan on converting to
MAP based DFI for my car this year, as the ECMs are becoming cheap used, and
I have access to pretty good "starter" fuel and spark maps for my
combination.

Bob Bailey may be a lurker here, or see Modern Muscle's web site for more
info; they're the distributors.

Kendall Frederick

> -----Original Message-----
> From: owner-gmecm@diy-efi.org [mailto:owner-gmecm@diy-efi.org]On Behalf
> Of nacelp
>
> > 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
>

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