twohoos

...an adjustable fuel pressure regulator (a la Prolene's, say) and a V-AFC? (Let's neglect the programmable VTEC point in the latter.) Are these just different products meant to achieve the same thing (better air/fuel mixture)? Or can (should) they be used together? Pros/cons?

Thanks,
John

Wesmaster

From what others have explained to me:

The AFR is just a "rising rate" regulator. As boost goes up so does the fuel ratio. With V-AFC you can map the air/fuel based on RPM. You could have different settings for low, mid, high RPMs, etc.

Taken from this thread:
https://www.s2ki.com/forums/showthread.php?...?threadid=21233

Wesmaster

texan

The difference is one is an adjustable mechanical device which regulates fuel line pressure (which is how it increases fuel delivery), while the other is an electronic device which modifies ECU input data to get the desired change in fueling output (by way of injector duty cycles). Further, there are two types of fuel pressure regulators, ones that are only adjustable in static setting and others which are boost sensitive and can ramp up pressure based upon MAP readings. The AFC has a much greater range of adjustment and can be dialed in for many RPM points, the fuel pressure regulator simply crnaks up pressure and thus supplies increased fuel fow ability at all times. Yes they can be used in conjunction, but that wouldn't be necessary unless injector duty cylces were rising above 80-85% (above which injector performance can become unstable). You can further use the AFC to mostly compensate for larger injectors, thereby still not needing a fuel pressure regulator. Hope that answers the basic questions.


Ps- To figure out how much extra fuel flow you get for a given line pressure increase, use this formula...
F2 = (*square root of (P2 / P1) ) x F1

where:
F2 is new static flow rating of injector (at higher pressure)
P2 is new fuel line pressure
P1 is stock fuel line pressure
F1 is factory static flow rating of injector