does it just reduce smoke and thats it or is there a performance gain

 

It's a lighter spring for the AFC housing. The 215 pumps have a very stiff spring and this makes it so it takes less boost pressure for the lever to hit the plate and pour on the fuel. Bottom-end kicks in way harder, and throttle response is snappier. But it smokes more.

 

actually, for the 215 pumps, it's designed to allow you to bring the fuel in quicker without smoking as much...

a lighter spring will change the AFC curve... on the 215 pump, in order to get the boost in nice and quick, you put so much slack in the spring, you get a HUGE belch of black smoke when you lay into it... some people don't like that, so a lighter spring will allow you to put some tension on it, so when you nail it, it doesn't dump as much fuel, but it takes less boost to compress the spring, so fuel comes in quicker.

(don't get me wrong, it's still gonna smoke, but it'll allow you to pick how dark you want your "haze" vs. how large you want your CLOUD!! LOL!)

it's just another tuning aid...

I've noticed slightly better acceleration and a lot less smoke when I set my AFC so that the spring is about .025" off the wheel (vs the wheel full forward)

but I've noticed fewer tailgaters and still VERY good acceleration when I run the wheel full forward...

now... when I REMOVED my spring, I noticed poor WOT acceleration from off-boost conditions and a REDICULOUS amount of smoke... it was fun for a day or two and then the spring went back in.

if you've got something other than a flat fuel plate, you may not have the same problem.

Forrest

 

"I set my AFC so that the spring is about .025" off the wheel"

Forrest, I'd like to do that. When I turn the star wheel where do I look for the gap? Does the housing location have an effect on this setting and is a spring kit necessary? I have a #10 plate set about .030 forward of the middle. Thanks.

 

you'll see what I'm talking about... as you turn the wheel more and more forward, you'll see that there comes a point where there is slack in the system... most guys run their star wheel all the way forward. it puts a pretty large gap in there... the .025" is an estimate... maybe closer to .050" bottom line is I didn't actually have any tension on the spring, but there wasn't much slack in it at all.

now, I've got a plate that's ground completely flat and pushed all the way forward, so when I floor it, it dumps fuel hard, and when the boost comes in, it pushes that lever way forward and it puts out a lot of smoke... if you've got a plate that actually has a nose on it that isn't as far forward, you may not have to run as tight a setting on the AFC to get the smoke to where you're comfortable with it.

playing with the AFC wheel is an easy adjustment that makes a huge difference in drivability. the one thing I did after I got tired of trying to wedge an allen wrench down in there and get it broken loose was to weld the head of a bolt to the plug. now, I just use a 10mm wrench to get it loose! (I also did that w/ my oil drain plug... welded an 18mm nut to it)

anyhow, just get in there and loosen up that wheel untill there's just the slightest amount of play in it and see how you like it... there'll come a point where more off-boost fuel doesn't help acceleration, it just puts out more smoke, and there comes a point shortly after that where it actually hurts acceleration a little. I like a happy median that can still put out a lot of smoke to ward off tailgaters if necessary

Forrest

 

i have my starwheel full foward so the spring isn't even touching it. will a spring kit work if i have it that far foward or would i just be wasting my money. i just ordered 370's i like the smoke the more the better

 

if you like a lot of smoke, the AFC spring kit isn't going to help you... the 370's will make a lot of smoke... that #6 plate will keep it from smoking so much that it slows you down... my flat plate is a smokey SOB!!

Forrest

 

PS, you might try taking the spring out and see how you like it...

 

i'll take it out this weekend i might grind my stock plate to a 100 also. first i have to see where my egt's are with my injectors. right now i can only hit 1200 full throttle for about 15sec

 

EGt's will be hotter w/ the 370's that's for sure, but it'll be fun!

Forrest

 

I'd like to do some of this stuff, but I'm worried about the excess soot clogging the cat on my truck. Will it?

Please, no discussion about what can be done to 'alleviate' that potential problem, just suffice it to say I'm not ready to do that right now..

 

yes, more smoke will clog a cat much quicker... there was a guy on TDR who lost his 100% bone stock engine (higher miles, but still) due to a clogged cat causing his EGT's to run high and do a melt-down job (no gauges, like I said, 100% stock)

I won't suggest anything illegal because the mods here are hypersensitive to that, but I am of the mind that if I own it and it's a diesel, it shouldn't have a cat on it. passing an opacity test is no problem without a cat.

Forrest

 

I did just as Forrest suggested back when I got my AFC spring kit in. Also adjusting the Zero boost setting really helps the off the line accell.

With the lighter spring, one click on the wheel isn't such a huge change, makes for nice finite adjustments. You can set the spring tension to have little to minor haze and fair accelleration, or pull your hair piece back smoke action.

I advocate the spring kit with the plate..

 

Okay... I'm still learning this 12v... where is the star wheel located?
Dave

 

there's an allen headed plug in the cover on the pump... remove the plug, and the star wheel is right there

Forrest