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since this is about fuel plate profiles... im trying to grasp what the fuel plate actually does and how it does it. im guessing that there is an arm w/ a tip which acts as a follower. the tip rides the leading edge of the fuel plate and this dictates the total volume of fuel allowed to be delivered to the engine... basically, it determines the fuel curve that a specific engine receives.

am i to assume that the bottom edge of the plate is off-idle or the bottom range of throttle angle/input? when the truck idles, does the follower sit below the bottom edge of the plate? does the follower move up the profile of the plate as RPM's increase or as throttle input is increased?

are the plate profiles dictated by supporting mods and the volumetric efficiency of the engine itself, or does it depend on something else that im unaware of?

im so used to building turbo gas motors and needing different fueling based off turbo efficiency ranges and boost levels.
 

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sweet... at least it puts a face to the name, now i just have to learn more about how this guy works. looking at the last pic reminds me of looking at a cartoony mouse trap set up, waiting for something to trigger all the action... but its hard for me to envision how the components interact during different engine operating parameters.

thanks
chris
 

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put simply, the AFC (aneroid fuel control) is there to handle fueling levels under no boost conditions. The pump has no sensory circuits to know emmisions and/or engine operating parameters. All it kows, is how to set the fuel rack for a given throttle demand, and to limit the top-end rpm of the engine. That's it. So the Aneroid takes this a step farther by sensing manifold pressure to cut back on fuel until MAP is present, at which time it pulls off and allows normal pump operation.

The governor arm contacts the "torque plate" only in high engine load, high demand situations. Most of the time the arm will not swing out and ride the plate....it is only there to limit rack travel in high power request conditions. Again, the pump is stupid, it will supply X amount of fuel for X amount of throttle angle. Without the torque plate there to tailor that fuel delivery, less than optimum fuel delivery is a result. Just like adjusting the ECM fueling maps in a gas engine, except this pump does it mechanically, with a profile and a follower, and the only adjustment you have is to curve your own plate, other than the cursory forward/backward movement. Now you know whay they call it a stupid pump. Doesn't even dynamicly time the engine either, which leaves a lot of decisions whether to static time it for power or streetability...cuz it's constant throughout the rpm range.

Chris
 

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well thanks for that run down chris... i kinda picked up on the AFC being the off-boost fuel control... i think ive got a good idea how the AFC housing and governor operates and limits total fuel availability when out of boost and part throttle.

i guess, now, i just need to decide which plate would best suit my ultimate mod level. all i want is a 600-700 lb/ft setup.
 

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all i want is a 600-700 lb/ft setup.
Boy have I heard that before!! You don't need to buy any parts to do that number!! Be careful...it's a very sticky road once you add that first horsepower.

Seriously...have fun, you'll never be the same. I've been building rods for 20 years and have never been seduced in the way this Cummins mill does it. Anyone else have this problem!!?!?!?

Chris
 

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lol... beleive me, i know about the slippery slope.

i dont know if you guys are familiar w/ Toyota supras... but it starts w/ an exhaust and a boost controller. it evolves into HUGE turbos, 96lb/hr injectors, multiple fuel pumps, stand-alone engine managment systems and so on. you start out w/ 300rwhp. before you know it, youre putting down 800rwhp!

i just dont want to take my motor up to a level where i could damage it by lifting the head or melting a piston or burning up the rings.

if my 10year old truck can hang with the NEW 5.9's, ill be satisfied for a while. i think thats a pretty good accomplishment to stand by for a little time...
 

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yeah but with nothin but bolt-ons and some head studs for good measure, 450-500 is pretty easy to get!! Just keep the EGT's in check and screw the head down a little better then she'll live pretty stress free without worry of giving birth to parts LOL
 

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I have heard, allthough it may not be true, that you can take a piece of flat iron say 3/8" or 1/2" and make your own fuel plate... Anybody know if thats true?
it can be done. But its good work!! a shop made a dozen for me a time ago! They looked almost like piers' and tst's etc
 

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I have a 97 25000 4x4 Dodge, At trans, if I move the stock torque plate all the way forward, will it put too much stress on my trans, or will it just add smoke with very little stress on drive train? I dont pull anything heavy, just my commercial mowers. Thanks
 

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the afc is not just for off boost, it is for no boost till you get to full boost, the plate is the full load rack stop. your afc is a great tuning tool. normal driving you will never even touch your plate, you will be on the afc arm.
 

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id like to gut the AFC housing cuz im willing to bet that the arm is probably set a little on the conservative side and sacrificing power as a compromise to find a suitable solution for the masses. i wouldnt mind manually controlling my boost-comp fuel delivery and having smoke on demand... i dont think ive ever just floored it. i usually eek it out of the hole and roll on the throttle after im over 30-40mph. i wouldnt be surprised if i saw no difference w/ the arm removed and the same driving style.
 

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so the star wheel just controls spring pressure on the diaphram to control how much boost it takes to move the afc foot out of the way??
 

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yup. if you loosen the spring it will take little to no boost to move the foot out of the way. the higher the spring load the more boost it will take to move the foot.
 

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If you slide the stock plate, does the arm need to be adjusted?
 
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