JDEstill said:
I really don't have time to do any searching on this, so perhaps you can tell me Bruce, what are the steps involved in, say, the BPC or BPW calculation for a GM speed density ecm? 749, TPI, whatever. I'm betting the gas law is in their routine somewhere. It might not be obvious, but I bet it's there. So tell me how they figure up the inj pw to command. They do some kind of A x B x C x D = pw, so what are all the A, B, C, D, etc they use to get there? If that P4 document doesn't give the right equation like you say, then what is the right one?
While I do appreciate your response, the original guestion is:
*Does anyone have any facts or data to prove that using a Ideal Gas Law, such as F.A.S.T. claims, does offer any better fueling than a BPC, or BPW calculation?, considering that the injector opening time, is just a fudge factor.*
As far as the P4 document.
In the P4 document, they talk about a inj constant, to use the inj constant in an ideal gas calc, you need some sort of engine displacement entry, to actually be able to figure out how much air the engine is pumping (ie VE). In the P4 document the code actually uses the BPW vs EGR flow, for the injector size.
Just to define what may be GMese terms.
BPC, is the TBI fueling where they typically don't use any IAT, or MAT for fueling.
BPW, is an Ideal Gas type fuel calc, but uses a BPW in lieu of an injector size, and cylinder displacement. The neat part of the 58 (syclone) code is that it uses a MAT, and you can see how much of a fueling correction there is based on MAT).
Then in like the 8D code it's an Ideal Gas Calc, and uses, an Inverse IAT Calc, inj flow, and cylinder displacement.
And in all of them they use a correction for injector opening times, based on voltage, and while typically 128'd out, there is also typically a fueling correction based on fuel pump voltage.