Engine/Transmission (1994 - 1998) new afc spring...who's done it?

[NBowlin]

who has swapped out their stock afc housing spring for the ones that Piers and i am sure others sell?



what did it do for you, if anything? also i know there is more that can be done up in that housing in conjunction with swapping springs to get a bit more rack travel.



can you folks who have done some of this let me know what i can expect as well as things to avoid. i was thinking of grinding down the face of the afc arm. not completely, but a smidge. i was told i would have bucking problems if i did this. any other ideas or things you are willing to share?



i have a 913 series pump with the 4kgsk and lasercuts. if i could afford a stoopid pump i would do it, but its not feasible. i know i cant get anywhere near that but there has to be some mods a guy can do himself. thanks.

 

[Andy Redmond]

There is a guy in NV, now NM that might argue that his sickly 913 pump can't keep up with the stoopid pump! Joe "can you hear us now"? Of course a stoopid pump can make a grin and hp too!



Seriously, the afc spring is softer and longer and allows the engine to fuel a bit quicker but still maintain some smoke control.



The kit comes with a medium and strong spring, use the spring with the heavier spring tension in your pump (it has larger diameter coils).



You can use the medium spring, but you'll have more smoke until boost is built.





Hope this helps, Andy

 

[NBowlin]

im trying to get what i can out of my pump on my own.

i am trying to get rid of the ubruptness in how it fuels right now. it kinda chokes up and then catches up all at once. i spose its probably being choked with too much fuel at once. i am trying to find the sweet spot for the afc housing, but i dont want to lose any fueling at the same time. i have been reading, calling and running ideas by people.



i talked to a bosch tech at the northwest nationals and asked him a few questions about the afc housing. he told me that mack has an application that does not run an afc at all. you can just cover it and run the plate, but you would be a smoky mess. i want the middle ground. good hard fueling without drowning my motor and bucking.



i know there are some pump genius folk out there. if its something that you dont want out here i will gladly accept it an a pm. all i have are icelandic shops and they are not much help.



would running more timing help counter this loading.



i am pretty sure with a little work and effort i can get what i want from the pump i have. i mean i have the tdr right? :-laf best money i have spent so far.



i have read A-bombs gov' control lever adjustment post a few times. like him i want to smooth it out, but i am not worried about the smoke at all.

 

[Jim Fulmer]

I've spent allot of time learning the AFC and it's little tricks most of which I don't talk about, but I figure if I've got a 215 pump truck with stock injectors running 1600-1700 degrees with a bigger housing and nothing more than a haze of smoke then it's got to be working.



It's all about spring tension, travel and how much boost it takes to get the arm to the point were you want, then it's about the arms full travel and what limits it, yes the different spring Andy was talking about is recommended as it's longer and has less tension.



Here is one for you to think about, how is it that I can run a big set of EDM injectors that will lay down 750+ on #2 and drive them on the street with no big smoke issues..... right foot at bay here... ... food for thought!



Jim

 

[Rams-n-Hogs]

Here is one for you to think about, how is it that I can run a big set of EDM injectors that will lay down 750+ on #2 and drive them on the street with no big smoke issues..... right foot at bay here... ... food for thought!

Ummmm, because us poor folk can't afford twins, PDR pump, stage II head, etc?



Jim

 

[NBowlin]

believe you me i am poor

 

[Joseph Donnelly]

With the 913 and big injectors, the stock spring is best if you want decent smoke control. Otherwise the TST "Medium" spring will be somewhat more responnsive at the cost of mucho smoke. Yes, Andy, I have seen a lot of hp from the 913 pump

 

[Joseph Donnelly]

And, some guys get real upset when I tell that I got the best dyno numbers with stock 181 delivery valves. (and the least smoke).

 

[Jim Fulmer]

Now that I have a real set of injectors I too dropped the DV's down to 181's, I didn't dyno test them against the . 022's I could just tell that I had way too much smoke and it was going to make me change them out to drive a long distance, not that it's a big job it's just not something I care to do.



Jim