kPa under boost

[Bruce Plecan]

----- Original Message -----
From: Glen Beard <gbeard1 at nycap.rr.com>
To: <gmecm at efi332.eng.ohio-state.edu>
Sent: Sunday, November 14, 1999 4:12 PM
Subject: Re: kPa under boost

Your at way less then optimum, IMHO..  (Assuming this is MAP)...
When you S/C an engine the VE goes way up, and that is all lost in the stock
setup, as your running it now.
  Just changing to a 2 bar MAP is no minor task.  It's not just a matter of
plugging it in.  The scale for the tables will be different, and when the
ecm reads it during key on- no engine run, it uses that as a baro
correction.
  The calibration (in the ecm) as your running it now, "pegs" at 1 bar
meaning it sees no difference from 1 bar to 12 bar..
  Your fuel pressure regulator (FMU) will give a slight increase in fuel
delivery.
But, the timing is constant from N/A to what ever level of boost your
running.

| "David A. Cooley" wrote:
| >
| > At 05:06 AM 11/13/99 -0500, you wrote:
| > >After reading the Programming 101 a couple times while trying to
| > >relate it to my car, I noticed in the fuel/spark tables that kPa
| > >maxed out at 100 (which corresponds to 14.5psia)  What would
| > >happen under boost from a supercharger?  What would the PCM use
| > >in it's fuel/spark tables if kPa were around 18.0psia?
| >
| > That's why you go to a 2 bar or 3 bar map and redo the fuel tables...
|
| If I need a 2 or 3 bar MAP for it to work, how am I getting by
| with the stock 1 bar MAP?  Is it because the FMU kind of uses the
| brute force method to alter fuel delivery?
|
| Also, I haven't heard of others going to a 2 or 3 bar map when
| they have their computer reprogrammed with larger injectors to
| get rid of the FMU.
|
| Do the kPa in the fuel/spark tables go above 100?
|
| --
| Glen Beard  95 T/A conv M6
| 355, Vortech, heads, cam...
| http://home.nycap.rr.com/gbeard1/TransAm.html
|