themud said:
Ok so I talked to hesco today and they recommend going the adj regulator route instead of the adj map and larger injectors because, and this is a good reason with 39psi to work with no matter how to fool the computer you still only have the volume of 39psi at WOT....With more pressure you have more available across the board including idle and partial idle, so after changing my tps I seemed to cut down on my long start up time but its still not perfect....
Somehow Hesco's thinking is strange (maybe this needs review)?
91' injectors ~21#/hr @ 39 psi
vs. the typical FMC 24#/hr @ 39 psi
Which of the two will flow more at WOT and 39 psi? (duh, the FMC 24 #/hr).
The 24 #/hr injector will flow up to 14% more fuel at WOT.
Dino's method:
So it may be rich at WOT (because the O2 sensor does not trim the A/F at WOT) but the firmware curves can be trimmed with the MAP (rather than reading 2" WG at WOT the MAP signals it thinks it's at 3.5" WG, and it runs a leaner A/F mixture path in the fixed algorythms).
Open loop conditions except for WOT may still read a little rich but the injector pulse rate will be adjusted slower by the adjusted MAP input to equalize the effor (both at WOT, and off-idle to WOT).
The mixture can be adjusted to run 0-14% richer than stock.
Hesco's method:
Now what if the regulator adjusts 39 psi to 44 psi.
What does a 21 #/hr injector flow at 44 psi?
New Flow = 21 * sqrt(44/39) = 21 # 1.062 = 22.3 3/hr.
Maybe the 91 injectors are ~22 #/hr (CRS?), they will still flow only 23.36 #/hr (the additional 6.2% increase in flow for the 5 psi increase in pressure).
The higher pressure will work everywhere in the computer fuel maps, closed loop (where the O2 sensor will trim the A/F mixture), and open loop (where you will rely on the MAT/MAP and rpm to locate the pulse rate for the injectors).
The result is the mixture can be adjusted for a 0-6% richer delivery of fuel at all times (and a possible increase in atomization, due to the pressure increase, but manufacturers also warn of flow problems at increased pressures).
The choice is yours ...