i gained 7psi of boost by putting an air filter system on my truck with a stock charger back in the day. stock systems are a giant let down. recently had to put the stock system back on the truck for a day or two while i fabbed a new system it made my truck near undrivable. absolutly horrid

hmm, air filter was my first mod after gauges... i saw 1-2 psi difference MAX... unloaded, maybe 5psi loaded...

I guess these trucks are just about as different as there are many...

I put the stock filter in after modifying it a bit and it dropped about 10 pounds of boost...

1998. And no, everything is in my sig.

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Which direction for more low end boost? I'm thinking about cranking my stock plate FF. Pulling a trailer on the highway is a real bummer as soon as it shifts into OD @ 60mph and my 2500rpm/30psi instantly becomes 1500rpm/10psi and it falls on it's face.

for more low end boost turn the top of the star wheel toward the engine, more fuel more smoke. turning the top of the star wheel away from the engine will give you less fuel and less smoke.

I don't care about smoke, just wondering how much sliding the plate forward is going to upset the balance of things regarding the other adjustments in the AFC, like the starwheel. While I doubt that the stock locations for everything are working together as well as they could, my concern is that adjusting the plate for more fuel and not knowing what to do with the starwheel in conjunction with the change will make things (power/mileage) get worse instead of better. For some reason all the hours I've spent reading up on tuning the AFC in here has left me with more questions than answers.

I suggest you move the AFC housing full forward, sliding your plate full forward will be good too but the pattern on the stock plate doesn't allow for much low rpm fueling...

just play with the spring until you find your desired setting, you can even fully loosen it and then tighten it from there... all it takes is an allen wrench and a flat screwdriver ;)

Well, today I screwed the starwheel FF to see what would happen. It seems to run smoother, and idles with a full 2psi more fuel pressure. It's definitely got a little more pep across the board. Too soon to tell what affect it may have had on my MPG, but I don't suspect it's gotten any worse because curiously, there isn't any more smoke than there was before. My guess is that with the plate still in the stock position, this little bit of extra fuel is all getting used. I assume that if I move the plate forward or put an aftermarket one in this will change, and I'll have to tighten the starwheel back up a bit to not waste all kinds of fuel out the tailpipe, but so far I'm pleased with the results of such a simple thing. I'll let it ride for a tank or so, then maybe move the housing forward. Then the plate? Dunno. Like they heard from the guy who jumped out the 10th story window as he passed floors: "so far so good, so far so good..."

For 100% tuning you will need to mod your AFC.. but you're off to a good start....

Don't spend money on a plate, just modify your own plate...

The pattern on the plate is shaped in the way that the foot will ride, it will start on the bottom and ride up as rpms increase, so if you leave a bit of material on the bottom of the plate, you will limit the pre-boost fuel...

I ground my plate to a #0, and had it set @ 75% full forward at first, then i slid my AFC housing full forward and completely released the spring, and then worked my way back until i could mash it without everything drowning in smoke...

You can feel that if you have your AFC spring completely loose with a fuel plate mod and AFC full forward.. that too much fuel will result in poor spool up, so make sure you tune it correctly..

I had mine set at a reasonably clean setup at first, here's a video of my old truck with my first mods after i fully tuned the AFC:


This was as you can see, reasonably clean... but would put ~360hp to the wheels...

Smoke is not always a good thing, although it can be cool to roll smoke if you go fast with it...

That does look like it's running amazingly clean. Plates are so cheap now that I'd just assume buy one, that way whatever I do is still reversible. It seems to have responded well to this step. Not substantial power mind you, but different enough that I no longer feel the need to turn off my OD around town to not feel like a complete turd. It's sort of like the TC feels tighter or something, like the stall is a couple hundred rpm lower. Regardless, I'll move the housing after I've run it this way for a few tanks. Do I need to worry about fuel gushing out while doing any of these AFC mods?

I suggest that you buy a kit for your transmission.. maybe even a converter too.

I'm not familiar enough with these 47RE/RH trannys, i'm all for the NV4500/5600...