Opinions on the Soft AFC Spring Kit

[Cummins Driver]

I finally got dad to let me play with the plate on his stock 98 5 speed. It has had the AFC slightly loosened for a little while. So, I had one that I ground to work well with where his governor arm was set, and I put the plate around 1/2 way. Well, power was about the same as stock. Barely noticeable improvement if anything. So, I thought maybe it just needed to go forward some more. So, I slid it forward to where it is around 3/4 forward now. He doesent want a fire breather, just some more pep for driving and hauling loads(he has a pyro). I also left the AFC housing in the stock location to try and keep the smoke down.

So, I drove it after sliding it on up with no change at all. So now, Im kind of thinking what the heck is going on. So, in a last attempt I opened up the AFC and loosened the starwheel almost all the way(quite a bit of slack before the spring even starts to compress), and then went for a drive. Finally, some power:rockwoot: It runs great now, and doesent seem to get hot. Clears up the smoke once its on the boost, and slips the clutch in 5th(original clutch with 230k on it). It runs perfect for what he does with it IMO.

Anyways, I was just wondering if anyone had used the soft AFC spring TST sells. I think that would allow me to keep the starwheel a little tighter for less smoke off idle, but then it would be soft enough to allow the boost to actually push it out of the way to get full power(rack travel) once its got some boost.

He likes it now, he just doesent want much smoke, and its obvious to me that without blocking the wastegate, it doesent make enough boost to compress the stock AFC spring enough to let the governor arm even get to the plate.

Eric

 

[Kronic_187]

take the stock spring, grab it with 2 vice grips and stretch it about 1/4" so it takes up all the slack in the housing, back the smoke screw all the way out and loosen star wheel right off.... while your doing that u may concider doing this as well...
afc mods (lots of pics) - DieselRam.com

i'm runnin my AFC set like that and even running this hx35 with no plate and these 5x.014's it keeps the smoke down, unless i get the tranny locked up and lug up a phatty cloud for the import tailgating me....

 

[NickTF]

I'm running the soft tst spring right now in my 911 benched pump with no plate. With this 62/68 13cm SS s300 from ED I like it the best. Anything smaller then a 62mm s300 (smaller being spools faster) should have the light spring imho. I can't comment on stretching the stocker as suggested above but sounds like a good idea to save some money. I don't like the stocker though with the starwheel backed all the way out and no preload on the AFC because there's essentially no control due to the length of the spring being too short. If he likes the truck with the stock afc spring (not stretched), doesn't mind the preboost fuel, and uses the plate to keep temps in line i'd leave good enough alone.

 

[mondtster]

Buy the kit and try it. It is only ~$35.

I've used them and am satisfied with the results, although the light spring might be a shade too light if he is looking for little to no smoke. IIRC, TST recommends the stiffer spring for the 215 pumps, but that is subject to pump setup as well.

 

[Scooter's Roofing]

with stock injectors, the softer spring is nice for smoke control with a plate... when you get into bigger injectors and making 40+psi boost, the stiffer factory spring is the way to go

 

[Cummins Driver]

Well, the problem is that if you have the starwheel tightened enough to hold the fuel back a little on the bottom end, it doesent make enough boost to compress the spring enough to ever let the governor arm get close to the plate. So, now that it is loosened, I can move the stock spring about 1/4 inch back and forth in the housing freely because of the play. So it seems to me that the softer spring would allow me to run enough tension on the spring so that it will still hold the fuel back some right off idle, but it will quickly ramp up with boost.

Sounds like the soft spring would work pretty good in his truck then from what you guys have said. I dont know that he would ever buy it or not, but I was just curious because it seemed to me like that one be about the best way to go on a truck like his. He likes how it runs now, and 1200* with no smoke at WOT is about what he is running. If he decides he really doesent like the smoke it has now, i might see if i can talk him into it. Otherwise, i think he's pretty happy with how it runs, and if you roll into the throttle, smoke isnt much of a problem.

I wouldnt mind to try the light spring in my truck. Maybe ill order the kit one of these days just to play with it.

Eric