any mask that uses a BPC/BPW is really a fudge to being with... trying to use that conversion for MPFI engines doesn't work at all, last time i remember trying to do it.

example: 3.1MPFI 60V6 = 16.7 lb/hr injectors(6 of them, obviously), factory BPC at 0% EGR is 224.

.517 L/cyl volume
2.1 grams/sec per injector

.517/2.1 = 359.8

i really can't come up with a reason for a BPC of 224 using that calc... making the injectors "appear" as a TBI setup could be done by multiplying flowrate by 3, so that it will seem like 2 50.1 lb/hr injectors, the calculated BPC comes out to 119.9....

if you then try to account for the injector firing scheme(alternating TBI(two injections from all injectors per revolution???) vs double-fire MPFI(one injection from all injectors per revolution)), i guess you could multiply the 119.9 by 2 to come up with 239.8, which is at least somewhat close to the factory BPC of 224, it's off by 7%, which is within O2 correction range.



in any case, i just take known values and multiply or divide depending on difference in displacement or flow... tends to work out pretty well.