Re: Turbo V6 Tuniing continued + Benchtop ECU

["Jeff M" <tystorm@email.msn.com>]

Nice results testing Barry.  As for injector flow rate, first; in the chip I
was working on, and since it seems to not be exactly like most talked about,
I wanted to cover all the bases and re-scale all things to do with fuel
injector sizing, second the owner was complaining that his Digital
Information Center (DIC) was showing 66 mpg (after I made changes in other
areas for his bigger injectors) to the point of wanting to seek help to make
changes in the DIC to get the MPG corrected so, doing the change to the
injector constant got his MPG readings back to normal.  The Sec/Gm setting
(labeled such in my book but I too think it is Gm/Sec ;-) in this chip was
also scaled just to make sure I covered all the bases (and that it was said
to be used for calcs in the chip).  As for EGR BPC, as Ludis said, only when
EGR areas are enabled so up to that point/ A/F is based off other areas but
for sure, I want to try this test this weekend to confirm in this chip once
I re-enable EGR.  As for injector linearity, there are a few tables that
address this in the chip such as based on BPW and Batt volts, but you would
have to get the proper values for the 40 pounders or make an educated guess.

Jeff M




> Did some chipping on the 7749 on the bench just now, attempting to change
> tables from 29# to 40# injectors:
>
> EGR enable temp (@$6CD) = raised to max (therefore, never active)
>
> Injector Flow Rate (@$328)= Zeroed (from 4.9 Gal/Hr)
>
> BPC vs EGR = zeroed table *except* for leftmost entry (@0% EGR):
> (@$40E)      this was set originally @ .108 for BG's 10/1 chip
>              using 29# injectors - changed to 29/40 * .108 =
>              .081
>
> Injector pulse width at 1000 RPMs on the benchtop went from 3.2ms to 2.4,
> which is exactly as expected from the above changes.
>
> So:  -The Injector Flow value indeed is not used by the ECU.
>      -Changing the BPC vs EGR seems to be the equivalent of a Injector
Size
>                         constant.
>
> If you had a decent running chip and merely changed injector sizes, would
> you not change this (BPC vs EGR) *first*, and then do your fine tuning
with
> the VE tables, etc?  I'm assuming linearity to be the same between
> injectors, which may not be the case, but its a place to start.
>
> Opinions, please - Barry
>
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