AFC simplified

OrangeNV said:
for a 66 that sounds great, but you can always adjust the preboost a 1/4 turn this way or that way to make it better, never know unless you test it

thats why i have a flex shaft hooked up to my pre boo st so i can give it a small turn up or down to make the fueling perfect due to weather changes
Click to expand...

Iv been tinkering with it for a few days now and that's about the best it will get.
 
In your situation Tyler, I would stretch a stock 215hp AFC spring to get ~ 45psi open pressure, try it. Then take a stock 180/215hp governor spring and try it, use which one works better in your opinion.
 
Can that AFC lever adjustment be a fine adjustment of the AFC to alter the off idle fueling curve some on a stocker?

TIA
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After looking at the pics on page one of this thread, I think I have an aftermarket AFC spring. It is the exact same height as a stock 215 pump governor spring and quite soft. I swapped the gov spring in just now....that was a mistake! Looking at the opening pressure now I see why. So, I imagine a gov spring like I'm trying would only make sense in a much higher hp/boost truck than mine, right? Without the no-boost screw cranked right in, the charger wouldn't even light.
 
Another quick question that seems thread-appropriate. Sadly, I have a '0' plate. Due to my stock afc, with the plate any more than 1/2 forward, the governor lever doesn't ever touch the plate, right? Or does the governor arm go up above the afc arm and contact the plate that way? Still trying to wrap my brain around what goes on in there as rpms and boost come up. Here's a pic showing that if the plate were slid anymore forward, the afc arm would be the limiting factor, rendering the plate useless...unless I'm missing something....

afc.jpg
 
G1625S said:
Another quick question that seems thread-appropriate. Sadly, I have a '0' plate. Due to my stock afc, with the plate any more than 1/2 forward, the governor lever doesn't ever touch the plate, right? Or does the governor arm go up above the afc arm and contact the plate that way? Still trying to wrap my brain around what goes on in there as rpms and boost come up. Here's a pic showing that if the plate were slid anymore forward, the afc arm would be the limiting factor, rendering the plate useless...unless I'm missing something....

afc.jpg
Click to expand...

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WAYNES WORLD
 
The AFC foot will move forward, so the face the gov arm hits will be behind the plate, depending upon housing placement and how deep the plate is. If its a deep cut plate and the housing is all the way to the rear, you may never actually contact the plate.
 
Yeah, that's what I was thinking. In the picture, the afc arm is all the way forward with no spring installed. The plate is set in what I would assume to be full forward position, and it's clear to see (I think...) that the plate is several mm farther forward than the AFC foot, rendering the plate useless. I'm not trying to point out anything new here, just wanted to see for myself on the bench what actually goes on. Apparently a stock afc with a 0 plate means you might as well toss the plate. For me, I've already got more fuel than I can use, so it's not worth grinding for max rack travel anyway. I'm used to tuning on VE's, so this is a new game for me...the afc is mucho important for a street driven truck, imo.
 
In the example above, your plate would be full forward, and you housing is full rearward. If you moved each closer to the middle, you'd bring the plate back into play.
 
Ok, now I see how afc placement on the pump would change the relationship of the afc arm and the plate...never gave that a thought. Still, it seems like the amount of forward/backward travel of the afc couldn't make up for that big of a gap in the pic, but maybe it could. This is all moot for me, though, as I've said, I can't use he fuel I've got. Just talking out loud and trying to learn. I've got my plate just back from center now. With the smoke screw in too far (will billow from idle if I mash it) I still can't light the charger with the gov spring in, starwheel loose. Should I go back to the old spring (of unknown origin) or keep messing with the AFC? Housing is about 3/4 forward.
 
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