fueling at wot and afc tuning
 

well im going to do the afc mods (replace the cupped washer, and grind the rod) i want to check to make sure its tuned right using an air compresser. now my truck makes 32 psi do i want to adjust the starwheel so that the foot is all the way forward (wot) when i have my highest boost 32 psi? what would provide the best power to spool up ratio ? or should i have full fuel a little sooner? so i can hit it in a lower gear? Also where can a get a mack rack plug and will someone discribe to me what it is

you can get the rack plug at any mack dealer. it goes in the front of the injection pump to allow u more rack travel, 2mm i believe. in order to get it in there you have to either grind the timing case or loosen the injection pump bolts. i ordered one n put it in when my kdp fell out n i had the timing case off.

The starwheel will not help your turbo spool faster. It is all in the smoke screw and it takes patience to get it right. But once you do, it goes. Than you can start playing with the starwheel.

when i mess with my star wheel it affects the boost and spool. the looser the star wheel takes a lil longer to spool and have less boost than when i tighten the star wheel it spools faster and make more boost

yeah the starwheel as alot to do with spool up time :argh: it controls how much boost is needed to move the foot forward to fuel harder. you can use a air chuck to tune your afc while off the pump and by setting the compressor to what ever psi u want full fuel at thats how you adjust the star wheel to allow for ff movement under that desired psi. what my question is should i tune the afc to have full fuel at wot under my peak boost of 32 psi for the most power or should i allow full fuel earier in the power band say 20-25psi and allow it to build to 32 psi?

starwheel is pre boost fuel... fuel plate is wot fuel

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the afc mods will help with more wot fuel. also i pulled my plate and that gave me more to

so will my truck benifit from pulling the 100 plate and running plate less along with the afc mods or is there not a significant diffrence in fueling between 100 and plate less. or just grind the 100 flat?

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and i know the starwheel is pre boost fuel what about the screw under the cover on the back of the afc that presses up against the diafram is that pre boost too:humm:

No its not.

Setting up your afc with shop air is just about worthless, you can not predict how your truck will fuel and adjust accordingly when your afc is on the bench. Do all your tuning with the afc on the truck, see what works the best for you, it will take awhile.

I barely ever run a plate on any of the trucks I work on, only when there is too much fuel for the turbo to clean up.

you guys are funny.........no plate with a cover over the pump to keep debris out and eliminate the afc all together

You need to go over here and start at the top of the page. 5.9L 12V Bombs (Aftermarket) - Diesel Bombers It helps to understand how the pump works and the purpose of the afc before you dig into it or give out the wrong information. Starting with air gets you in the game before you start. Different pumps will have different spring rates on the star wheel. I've seen it take 40# to max one out. You need to know this before you start.

http://www.powerstrokenation.com/pho.../swap_0052.JPG

i understand how the pump works :argh: im asking a simple question that has not been answered yet. i guess ill just try a few diffrent set ups. And shop are does work or at least puts you in a very near ball park and minor tuning can go from there. air is air whether its compressed air coming from the turbo or shop air it will get you close enough to fine tune from there. as for plateless this is a street truck i dont have enough charger for no plate and the injectors i have so until then the 100 plate will work as it is i can almost snuff out the charger with the sticks and plate ff afc ff and starwheel all the way back. :humm:

The remarks I previously made were not entirely directed at you. In an ideal situation has the AFC full forward just before full boost. You can use a washer on the rack cap to space it out. Does the same as a Mack rack plug.

Ever think the turbo lights different then a air compressor?

Pressure is pressure. :w2:

You dont set your afc up for max pressure, you set it up for low end spooling.

And just what do you do if you don't make enough boost to max out the AFC? Do you just say screw it I didn't want the extra fuel, my truck runs good enough. It's called tuning, if you want it "all" it takes an some extra effort to get it.

If your not getting enough boost to compress the spring you have the wrong spring.

perfect thats what i needed to know thank you


chris

That is why you bench check it with air.

Thats why you dont let some tard put a stock governor spring in your afc :c: