When VE values reach 100%

[Walter Sherwin]

>Ok, I have been slowly modifying my VE tables on my 7747 setup, well
>after I installed the new head, header and cam I have found that even at
>100% VE the upper RPM's at WOT could still use some more fuel (with BLM
>locked at 128 the INT still goes to over 150.  What is my next step?  Do
>I increase the injector constant for these rpm/map ranges and then
>reduce the VE values and start over.  I also thought of increasing fuel
>pressure but that would screw up the rest of the VE table, as would
>adding larger injectors..  Just some food for thought
>
>Jason Weir





Jason, if you are at an "FF" at the high RPM VE table points, then you
should think of either  1)larger injectors, or 2)more fuel pressure.   From
a programmatic standpoint, both are equivalent.  However, you can
substantially raise the fuel pressure, and avoid having to purchase new
injectors, which saves $$$.

Don't know for sure about your "747" cal, but would suspect that you would
have to recalibrate both the EGR OFF injector constant and the EGR ON MASS
tables to suit the "new" fuel delivery, in either case, to do the cal
correctly.

However, you could also use Dr Bruce's idea of an external in-line return
regulator with vac compensation, which would raise the fuel pressure only
during WOT (low vac condition).  With such a setup, you can retain the stock
idle fuel pressure and calibration constants, while experiencing a WOT fuel
benefit.


Walt.