2nd Gen Non-Engine/Transmission AFC vs boost onset relationship

[McLaughlin]

Can anyone explain how changing the AFC housing position, fuel plate, and fuel screw positions affect how fast the turbo builds boost?

 

[Forrest Nearing]

rack travel = fuel



sliding the AFC housing will dictate how much initial fuel you get when you hit the pedal. now, if you loosen up the star-wheel a ton, you can get even more, but with tension on the spring, the housing position dictates pre-boost fuel for the most part.



you can also adjust the set screw on the back of the AFC housing (have to remove the tamper-proof cap) to fine tune this setting.



fuel plate profile can certainly effect how the turbo spools up, but I prefer to run a very deep agressive plate, and let the AFC control the spool up for me.



you'll just need to play with everything to get the right mix of spool vs. smoke... some people can stand more smoke than others. I don't mind a good haze, but I can't stand looking like a rolling tire fire also, there comes a point where a bunch of fuel and black smoke will hinder spoolup

 

[McLaughlin]

Thanks, makes sense. Only painful part is readjusting the fuel plate.

 

[Forrest Nearing]

nah, shouldn't take more than 5min to move the plate... leave the pass front bolt off the AFC cover... I don't think I've ever run one on any of my trucks



undo the cover bolts, pull the solenoid down (don't touch the back bolt, just the top two), move the housing out of the way, two flat head screws, and reverse.



if it takes me 5min to move the plate on my truck, I'd be surprised.

 

[McLaughlin]

Humm, haven't tried it that way. Worth a shot, its a lot simpler then I've done it in the past. Actually removing the AFC cover isn't that bad now that I've replaced the top slotted bolts with allen bolts.

 

[Forrest Nearing]

good plan... try leaving the one hidden under the injection lines out... at least while you're fine tuning. even with it in, if you use a long ball-nose t-handle allen wrench, you don't need to remove the intake hat or injection lines.



I always used to completely remove the fuel solenoid till my buddy looked at me cross-eyed when he was watching me and pulled a "watch this" move... just undo the top two bolts, and pull it down (pivoting on the longer horizontal bolt on the back)



works great