I tuned my AFC by changing the washer and grinding the shaft. I replaced the spring and set it to max travel @ 30-35psi. But, I used a lighter AFC spring, not a heavier one. Now after reading some recent post, I'm not sure that I have the right spring in.

Just to go over this, comparing a light AFC spring to a heavier one, while both being set for max travel at 30psi. The lighter spring is going to come on earlier and add fuel more gradually than a heavier one that opens later, but fuels at a faster rate. Is that right, or do I have that backwards?

Either way, it would seem to me that the AFC spring should match your turbo and injectors. If you have a smaller turbo and injectors, then you can add fuel earlier than if you had larger injectors that would put out the fire if fueled heavily too early before the turbo lit. Is that right?

I have the Mack Plug, can I still get full rack travel even if the AFC isn't slid all the way forward? I'm trying to set it up for MAX POWER, but I don't want anymore black smoke than need be.

 

the lighter spring will fuel harder ppl with big injectors usually put heavier springs in, but lighter spring then you might just have to crank on it harder to keep hold back on fuel that is all,
did you buy a washer or just grind yours?
i would put the housing FF, and back off the smoke screw to make up for it

 

if you ground .090 or more off the barrel than yes you can get max travel with the housing all the way back. With the housing all the way back you may have to play with the pre boost screw to tweek the low end fuel a little bit.