Originally Posted by TTSC3

Actually, using an SAFC to control large injectors does "work" to control JUST the A/F at a basic level, but you need to understand what's going on beyond the A/F that you're correcting. Since the SAFC doesn't control PW, and only alters airflow, you're gonna run into much bigger problems with too large an injector, and that's timing advance. The stock ECU has timing maps that are ALL airflow based. The less airflow the ECU sees, the more it'll advance the timing. So while you can look at the A/F and be at a perfect 11.5, if you pull out too much airflow, the timing will advance itself A LOT. Pulling out 50% fuel on an SAFC is dangerous, and most people don't even realize that the cylinder pressure is increasing because they don't know what the SAFC is doing when used under conditions like that. If you're going to use an SAFC to tune with very large injectors, use an AFPR to basically "trim" the injectors capacity at WOT. The drawback to this is that the bottom portion of the map becomes hard to tune, but I'd take an erratic idle over a blown motor any day of the week. I do professional dyno tuning on AEM's, Motec's, ecu reflashing, and have done pretty much all the piggybacks, and have seen this happen way too much.

Originally Posted by Blk97SC300

If my calculations are, in fact, wrong- then how was I able to successfully control 650cc injectors on my 3000GT VR4? (stock size = 360cc).

There were guys on 3SI running 720cc injectors on their VR4's. 720-360 divided by 720 is 50% correction- which was in the ballpark of where they were at.