heavy afc spring

[Don Tanklage]

does anyone have a extra one laying around?



my truck had the multi colored (soft) spring in it when i got it



i would like to try the silver colored heavy one



or at least throw it in my spring tester and see how much stiffer it is



thanks



don

 

[Makaio]

Don,

The two-tone red/green spring IS the heavier one. Put the silver one in there for a little better spooling.

Aloha,
Matt

 

[Don Tanklage]

oh, my bad...



well, the star nut is all the way at the top and this spring is still too light for my set up



there is a big spring manuf in L. A.



i'll find something that works the way i want it to



thanks



don

 

[Makaio]

Don,



Your starwheel is all the way to the top? That will put MORE pressure on the spring. Crank it DOWN for faster boost. When you go down, you increase the space between the top cover and the bottom of the spring, hence less pressure on it. Starwheel to the top will compress the spring more, hence boost will come on slower. Does this make sense? I would draw you a diagram but I suck at Photoshop. Hope this helps you.



Aloha,

Matt

 

[Philip]

I have a spring from a diesel dynamics fuel pin kit. It was the same rate as my stock spring was so I never installed it.



The DD fuel pin was junk. I had it in the truck for a 30 minutes and pulled it back out. :-laf:-laf



That was a wasted $75. for the kit.



If you want to try it send me a PM. I'll trade you for the soft spring.

 

[Don Tanklage]

thanks



the problem is that i am getting full fuel before full boost



trying to figure out something that will work for towing



don

 

[cerberusiam]

thanks



the problem is that i am getting full fuel before full boost



trying to figure out something that will work for towing



don

Ummm... . turn the pump DOWN! :-laf

 

[Don Tanklage]

i turned the pump back down BEFORE i started tuning on the afc



afc is still coming in too quick with the star nut at the top



which spring is heavier?



green/red or silver?



thanks, don

 

[dpuckett]

Don, are you getting full fuel or full smoke before the turbo spools? Reason I ask, is that once you get past a certain piont, the AFC does very little. I cant imagine running the pump without the AFC. ALso, your injectors and/or pump could use some refreshing. I had a nonIC 91 that got down to about 14mpg city, and smoked all the time. Got the pump gone through, injectors redone, and gained 5-6mpg.



Daniel

 

[bgilbert]

I've got a red/green spring from an intercooled truck, it's definately not the stiff spring. The spring that came out of my 89 pump is silver and is STIFF.



The only other thing I can think of to slow the rise of fuel per boost is a smaller afc tube from the cylinder head to the pump top. 1/8th tubing and fittings will slow it down more than the stock metal tube.

 

[Don Tanklage]

Don, are you getting full fuel or full smoke before the turbo spools?

yes, not if i drive it real easy, but if i pretend the trailer is back there and roll on it a little bit more it smokes a lot. and if i roll quickly to say 1/2 throttle it is black and thick.

Reason I ask, is that once you get past a certain piont, the AFC does very little.

what do you mean??????????? i turned the pump way down, to where i could just get it to idle then in maybe 1/2 turn. rigged it so the afc lever was held to the 'no enrichment' position. set up like that the truck wont smoke. made the afc functional again and it smokes like crazy. maybe when you have the fuel screw maxed and the case pressure is really high it doesnt do much but turn down your pump and tune specially the afc, it can add a lot of fuel (imo)

I cant imagine running the pump without the AFC.

w/o as in full afc enrichment or no enrichment??? i had to try it both ways in order to learn how much it enriches the mixture. even with the fuel screw all the way in it makes a huge difference on my pump.

ALso, your injectors and/or pump could use some refreshing. I had a nonIC 91 that got down to about 14mpg city, and smoked all the time. Got the pump gone through, injectors redone, and gained 5-6mpg.



Daniel

yea, that is what i was getting at with the "on my pump". i think it was on its last leg (remember, this is the truck that i drove for years with a weak lift pump). loaner inj are in the mail, coming my way. i will try them first. still wont learn much, it is way too much for this turbo set up like this. should have the new turbo soon, and once i get that all installed i will dyno and get a baseline. i have a feeling the pump is gonna have to get freshened up if i want to get the most out of this thing. where do i send it??? (i want the best there is, dont care about cost as much as i do quality. i will not send it to anyone that does not have a flow bench). who is there to choose from???



thanks



don

 

[Don Tanklage]

I've got a red/green spring from an intercooled truck, it's definately not the stiff spring. The spring that came out of my 89 pump is silver and is STIFF.



The only other thing I can think of to slow the rise of fuel per boost is a smaller afc tube from the cylinder head to the pump top. 1/8th tubing and fittings will slow it down more than the stock metal tube.

thanks billY bob, now that we have that settled...



yea, maybe you are right, a smaller line... . or what about a regulator? one of those cheap plastic ones? if the reg was set low would it slow the rate or just limit the max pressure?



i just redid the line (remember, my stock tube was broke). did it with -3 AN stuff. turned out nice, would post a pic, but i am not at home, will post it tomorrow. -3 is only . 187" i. d.



what about that silver spring? are you using the one from your '89? with the star adj that might be heavy enough for what i am trying to get it to do. would love to try it...



don



ps - do you mind your new nick name? hope not. i think it sounds cool... just let me know if you are not alright with that... of course, if you say dont call me that you know everyone will



sorry - i am good with numbers but bad with names, wont forget yours...

 

[Don Tanklage]

trying to figure out how to post a pic...

 

[therabbittree]

whats with the preload on the fuel pin / spring? looks like that could mess with your system a little. . ? ie give you more Fuel. . I thought you wanted less ie a stiffer spring?

Thanks

Deo

 

[MEby]

Thanks for the pic Don, it gave me some ideas.

 

[Don Tanklage]

looks like that could mess with your system a littel. . ?



Thanks, Deo

i am all about 'messin with the system'



thought you knew...



don

 

[Don Tanklage]

Thanks for the pic Don, it gave me some ideas

your welcome



please dont forget to share your thoughts



that is what these free forums are for...

 

[dpuckett]

These forums are NOT free- they cost nearly $3 a month!!! :-laf



Don, by "running with no AFC", I was referring to Greenleaf's gutting of the pump top and basically making it a full fuel off idle industrial pump.



Does it make any difference in smoke level if you wait til, say, 1800rpm to roll on it? Or is it strictly a smoke at 1/2+ throttle, no matter the RPM? Mine will leave a good cloud if I get on it under 1500. 12cm hot side, and 60mm cold side make it nice in traffic. Towing a 2640 John Deere on a 18ft carhauler trailer, it did very well in the hills, both smoke and EGT.



Once you get past a certian point (in cranking on the full fuel screw) is what I meant about rendering the AFC useless. I guess it always cuts fuel, but once you get to a point, the adjustments do less and less overall, and one must use his right foot to control smoke. Or get a bigger huffer.



For pump rebuilds, Scheid's, PDR, Bryan Banghart, and Northeast Diesel Service (Jackson MO) are good, though Northeast doesnt have a whole lot of performance rebuild experience. Red Oak Diesel from somewhere in NE claims they were rated 2nd in the world by Bosch. That is the shop on ebay that has the "+ 1-3mpg" injectors for each generation. From the people I have asked, the claim isnt too far fecthed. I need to find a 26mpg 1stGen, and see if I can get 29 from it.



DP

 

[Don Tanklage]

Don, by "running with no AFC", I was referring to Greenleaf's gutting of the pump top and basically making it a full fuel off idle industrial pump.

ohhh, for my notes i consider that condition 'full afc'. short for 'full travel of the afc lever'. i have not totally removed the lever from my pump, cuz i need to be able to tame it down later for towing (like next weekend)

Does it make any difference in smoke level if you wait til, say, 1800rpm to roll on it?

yes, if i wait until 1800 it is not nearly as smokey cuz the boost is right there

is it strictly a smoke at 1/2+ throttle, no matter the RPM? Mine will leave a good cloud if I get on it under 1500. 12cm hot side, and 60mm cold side make it nice in traffic.

i am talking more about stop and go traffic. if i give it 1/4 throttle with no boost the thing will smoke like crazy

Towing a 2640 John Deere on a 18ft carhauler trailer, it did very well in the hills, both smoke and EGT.

that is good to know, it sounds like the turbo that htt is sending me is very close to what you are using

Once you get past a certian point (in cranking on the full fuel screw) is what I meant about rendering the AFC useless. I guess it always cuts fuel, but once you get to a point, the adjustments do less and less overall.....

again you have lost me i have tried both different extremes - fuel screw bottomed and no afc vs. fuel screw backed all the way out and full afc. imo the position of the afc lever (in the pump body) makes more difference than the position of the lever the fuel screw pushes on



is this cuz my pump is on its way out or have others found the same results???

For pump rebuilds, Scheid's, PDR, Bryan Banghart are good. Red Oak Diesel from somewhere in NE claims they were rated 2nd in the world by Bosch.



DP

thank you for that info. the more i think about it the more i lean towards starting with a brand new pump instead of a rebuilt pump



any thoughts on that????



(i know these things are set up new with some very close tolerances, maybe there is no way to duplicate that when the body has 200k on it???)



thanks again, don

 

[Moab4x4]

Valet Switch for towing

I have a solenoid inline with the afc boost so I can turn on of off the boost at will. When I first fired things up after the BOMBs hit, I was at 32 PSI boost with or without the solenoid. I had my fuel a little to high. I backed off the fuel to 24 PSI with solenoid closed and 32 PSI with boost enabled afc. I noticed not a lot of difference at the top end power level with my mods. The switch gave me ~70 HP at will according to the dyno. I don't have enough air to burn all my fuel anyway so I am OK with this setting.

I leave the switch off when I tow to keep EGT down and can always turn it on for that quick boost.

My AFC spring (same colors as yours) is near the bottom on the starwheel and the fuel pin doesn't move until I am at about 5 psi boost. That is a ballpark number found by watching the smoke change as I turn on the switch at various boost levels.

Having that switch really helped me tune things with boost or no boost. Just don't mount the solenoid directly to the engine. The engine vibration can make the solenoid plunger bounce and really screw up your tests.

BTW, going to 1/8 line really didn't make any significant lag difference during my tests. Daniel is right on that one.



I think Cerberusium had it right, turn down the fuel to tow (or increase the air)

Ken