afc spring what does it do
06-09-2010, 11:00 AM
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afc spring what does it do
ok i have a 12 valve cummins it is out of a 96 dodge ram 2500 and i put it in a 2001 sort bed single cad dodge ram 1500 with all the running gear and stuff i rebuilt the motor and had the exhaust side of the head ported an polished i have a #0 fuel plate and a 4000 rpm gvs and im wondering what benefits there are to improving your afc housing spring im sure what it does and need some advice thank you in advance
06-09-2010, 02:49 PM
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the afc spring puts resistance on the afc foot/ slide mechanism that is connected to the pressure side of the turbo, so it does not allow additional fueling until the turbo builds boost. If you remove the foot or loosen the spring you are dumping more fuel in before the truck has boost, usually resulting in unburnt fuel (black smoke)upon inisital take-off, before boost is built and the motor can run efficiently again yeilding no or little black smoke.
06-09-2010, 05:14 PM
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so what is the benefit of upgrading the spring i have seen a afc spring as a power upgrade what does this do does it make it where you can adjust this more accurately or what just want to understand it before i buy it that way i know if i even need it thanks
06-09-2010, 07:14 PM
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Well, my take on it-
The AFC controls the maximum allowable amount of fuel for the boost you have. Cummins made the spring rate in for approximately 0-25 psi of boost, and meters the fuel accordingly.
If you have more fuel than you can burn with 25 psi of boost, and have more than 25 psi of boost you will need to increase the range where your AFC operates correctly.
Since the AFC is a pneumatic piston (pushed by boost) on one side and a spring on the other side, changing the spring rate will change the envelope in which the AFC controls your fuel delivery.
As long as you aren't massively overfueled you won't get more power- but you will get less smoke and better driveability with a properly tuned AFC.
Just my 2c
AlpineRAM
The AFC controls the maximum allowable amount of fuel for the boost you have. Cummins made the spring rate in for approximately 0-25 psi of boost, and meters the fuel accordingly.
If you have more fuel than you can burn with 25 psi of boost, and have more than 25 psi of boost you will need to increase the range where your AFC operates correctly.
Since the AFC is a pneumatic piston (pushed by boost) on one side and a spring on the other side, changing the spring rate will change the envelope in which the AFC controls your fuel delivery.
As long as you aren't massively overfueled you won't get more power- but you will get less smoke and better driveability with a properly tuned AFC.
Just my 2c
AlpineRAM
06-10-2010, 01:21 PM
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ok that makes sense and im going to say i dont need one because i am not over fueling i put out very little black smoke mostly black from a dead stop and im taking off hard but after that its a light gray witch from what i understand is what i want thanks for the info
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