Quote:
Originally Posted by UNISA JECS
The only thing the SAFC is gonna do with regaurd to changing AFR's by increase/decrease the % on SAFC would be threw manipulation of calculated TP (theoritical pulsewidth) by altering the MAF singal and since all this is being done in cruise/closed loop condition, your not gonna get far, this is controlled by the ECU.
Since all these changes are being done in the low load cruise/closed loop portion of the fuel map, the ECU is only going to react by adjusting fuel trim to hit back the target AFR in the LOAD cell.
To make any real changes, you would have to go to the extreme settings of the SAFC to over come the fuel trim correction and then your asking for trouble because you'll be accessing higher load cells when in reality your in a low load situation and the vise versa.
IMHO the SAFC is only good at getting your car to idle with larger injectors and thats all, shouldn't be used as your soul source for tuning. I myself have used a SAFC since like 2000 in turbocharged cars so im not a hater on teh SAFC but I know there is much better out there for a little more cheddar.
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I won't argue the tuning part of an S-AFC, as I don't like 'em when you use them on different injector/MAF combos than your ECU is calibrated for. But the closed loop fuel trim isn't as perfect as it sounds if you actually watch it on a wideband. Yes, there is a trim to get it pretty close to the target AFR(bouncing all over the place), but a change to the MAF voltage does tend to lean things out, especially since in general things are leaner on the lower load portion of the map on stock tunes.