thumbs

Ok as most know I just did the mods to the pump. I would like to know approximations as to the settings. First let me tell you where I am and the results.

Power adj.............1 turn cw
Smoke adj............2 turns cw
Diaphraim ............120*cw
Star wheel........... 1/2 turn cw

At 1750 rpm on a flat I run between 500 and 600*F.
I am able to get a little boost when the cruise control kicks in for an upgrade.
I also find the boost to start earlier but doesn't go past 10 or 11psi.
I run out of temp on acceleration before rpm so the housing will be ordered.
She will climb to 1000* pretty quickley so I gotta keep an eye on er.
I do get some smoke when accererating but it does clear as the rpm's increase.
Power is much better and she feels pretty strong now.

I think that is about all the info I can give ya. Now for some questions.

How does the smoke screw effect boost if at all. Can I adjust the smoke screw to get rid of the smoke without loosing power?

Now the star wheel. How far should I turn it in? I have it one half turn now. What does it control? I think it determins when the boost comes on right? If I turn it more I should get more boost at lower rpm right?

In general what is the proper ballance for these adjustments? I want to get the most out of it without hurting it.

One more thing. What it the general consensis as to the hp difference these changes made?

Thanks guy's. I'm just trying to get this tuned right. I don't want something unballanced.

Oh forgot to tell ya. Believe this or not. And let me qualify my numbers. I will normaly get about 20 mph empty on a trip. I just got back and to keep this honest it was pretty flat with a few stops and gos and held around 55 or 1500rpm most of the time. Look below to see how the truck is setup. For a 94 mile stretch I burned 4.2 gal. That's 22.3 mph. I got more power, played with it a bit on acceleration to feel the differance and got better milage with the mods. I will of course continue to keep track of the milage but that ain't bad at all for a w350 4x4 ;D ;D ;D

Lil Dog

Well So far so good it sounds. What you have to remember is that you are affecting the fuel to the engine, and not really the boost. The boost is a function of the fuel you burn and the amount of exhaust coming out of the engine.. Thusly you get more boost at higher RPM.

Now to control smoke at start off the smoke Screw or Aneroid screw pre-sets the fuel advance pin position.. In essence you control the amount of no-boost fuel to the engine. So when you first start off, thats the smoke you control. In your case if you have turned in the Fuel screw, I would back out the smoke screw to reduce no-boost fueling.

As for the star-wheel I have found that all fuel is not the answer. I had the star wheel turned to 1 turn out from bottom. (So basically you turn the wheel in tight and back it out). I found that I had loads of low end fuel but nothing left by top end. In turn I got horrendus EGT down low but it came down with speed. So recently I turned it out another 1.5 turns (total of 2.5) . Wow, what a difference. I didn't loose the low end I thought I would but rather have better, more smooth power down low and have lower EGT on the accel and the smoke is less. I get better boost at top end, gained about 1-2 psi.

My theory here without tearing a pump apart is that you defeat the timing advance of the pump by having too much fuel at lower RPM.. If you can balance the fuel down low with the Star-wheel you get a better timing shift at higher RPM. The VE pump has dynamic timing by nature and its my opinion that tuning for power is more than just bulk fuel.. Too much smoke and early fuel is not helping at all. I think Bushy has been researching this with his connections at PDR with some positive results. There is also a new fuel pin design coming out.

I think you will find that most guys with high output injectors are advancing their timing as well as increasing the spring pressure from the star-wheel to try to reduce their EGT's and still provide maximum power.

If you really want more power at low RPM, a turbo housing change will do that. The smaller housing will give you more air at lower RPM and help to bring down EGT's.

I hope this makes sense, I think I have re-edited this about 4 times.. :

J-eh

Alec

The mileage is good, but that is what you will get running at a steady 55 in O.D. -- which you can do after the pump is turned up.

You seem to have a problem, though. With those mods you should be getting more manifold pressure, and have lower EGT's -- at least running over 2000 rpm. If you are running around 1700 rpm, then the big housing might let temps get that high.

I would check the intake and exhaust for obstructions, if there are none, your aftercooler might be leaking, or the plate on top of the intake manifold might be leaking. I think that you checked your boots already.

There is a lever in the pump that controls how much fuel is dispensed per stroke. The AFC controls the stop for this lever, and the "power screw" controls the fulcrum for the lever.

By turning the AFC eccentric pin so that the deepest part points forward you have allowed the lever to travel farther, and by turning the power screw, you have moved the range that it's motion covers -- both giving you more maximum fuel.

When there is no boost, however, the AFC eccentric sets the "stop" at a certain point. Turning in the smoke screw, or building manifold pressure, causes the eccentric to be pushed in, which changes the stop position, and allows more max fuel. So turning in the smoke screw increases the amount of fuel available with no boost, turning it out decreases the fuel available with no boost. In general, turning it in makes the truck take off faster, but with more smoke (and less efficiency at take off -- smoke is incompletely burnt fuel).

Adjusting the star wheel changes how much boost pressure is required to move the AFC. Stock settings on the spring are ROUGHLY 2psi to start the AFC moving and 10psi to bottom it, but it varies from truck to truck as far as I understand. Turning the wheel down (rotating it clockwise from the top) will allow maximum fuel delivery to be attained at a lower psi, unscrewing it raises the manifold pressure necessary to achieve maximum fuel delivery.

In my opinion:

Your information makes me think that you have a problem with your intake or exhaust, and you are not generating the boost that you should be with your equipment and settings.

You need to remember that the only way you can increase boost at a given engine speed is to raise the EGT's or change the turbo configuration.

If you fix your leak/restriction, I will bet that you will be quite happy with how your truck performs.

ALSO it makes quite a difference if your pyro is pre or post turbo, and I don't see that in your sig?

Lastly, if I had realized that J-eh was going to post before I got this finished, I would have just let him answer!

Good luck,

Alec

Lil Dog

Alec pointed out a good thing with the lower boost numbers. I totally missed that :-[

J-eh

thumbs

Thanks guy's.

Lil Dog & J-eh My stock setting for the star wheel was 7/8 from all the way in, or 7/8ths ccw from the bottom. I can get my boost to start much earlier than I used to. But what you are saying is I should move up (ccw) to put more tention on the spring and diaphram right? In essents I was goin the wrong way. But that is what the directions on Gino's said to do. I started with 1/4 then 1/2 and then all the way cw which is 7/8th. That is where it is now. What you are saying is I should start at the stock position and move it ccw about a turn or turn and a half right? That will reduce smoke and my egt's with the same power. Is this correct?

Lil Dog

Alec and I were yakin here and its basically trying to manage the fuel with air.

1 Turn from the bottom I ran for a year.. I finally got tired of the smoke and EGT and tried upping the spring pressure.

Now this is the nice thing about mechanical systems, you can do what ever you want. But I think Alec is right in checking your intercooler boots, intake manifold bolts et al to ensure you don't have a leak. Then adjust your system the way you want it..

If you want to reduce a little of the low end fueling and shed some EGT, then try upping the spring a little more.

The thing about the fuel screw on the back of the pump is that it dumps about 75% of the increased fuel at lower RPMS and doesn't do as much at higher speeds.


J-eh

Jbolt001

Let me start by saying that the settings you posted don't mean much. For example my power screw from the factory was already at the stop colar. The star wheel was 1 -1/4 turns up from the bottom. Diaphram was turned about 20 degrees from the lowest setting and the smoke screw was about 1/2 in from neutral. Neutral being not contacting the AFC pin at all. What does this mean?? It means these were the settings chosen to meet the required performance for the factory. Each pump will be a little different. The best thing you can do is tinker and see what works for you. Settings with stock injectors will be vastly different than those with heavier feuling. Even the stock injectors have a range of pop off pressure that will influence these settings.

I did a mockup of the AFC a while back and took some real time travel measurements of the AFC fuel pin vs boost pressure and star wheel settings. Take a look at the charts I did based on these measurments. http://www.turbodieselregister.com/u...mp;albumid=638

Also take a look at the VE diagrams posted by Bushy

http://www.turbodieselregister.com/f...threadid=65478

Jay

thumbs

Ok, I guess what I am trying to ask is.....How do I know when I have things set properly? I wish I could express myself better so you would understand what I am trying to say.

For example:

Lets say my goal is to get as much power out of the existing system I can with the mods I can make. IE pump mods. That being said it has to perform well for everyday driveing and for pullin the 12k fifth wheel. Now where do I start? Do I start with the power adj and adjust the star wheel to some kinda of setting that will give me somekinda know results that will tell me I am right. Then go to the smoke wheel and adjust to the previous settings. Or some other kinda order like starting with the star wheel and adjusting the others to that setting. How do I know I made my goal and the system is tuned to optimal performance?

Ok all settings are different from the factory. Lets say they are ,like you said, set for some kinda standard. That means, again like you said, you can't give me an exact turn this adjust that so what is the goal? What should I see on my gauges and what other signs do I look for to tell me I'm set properly for my truck. Like up a hill wot (2600rpm) fourth gear, unloaded I should see 1000*,12psi boost and no smoke?
Which one do you set first and adjust the others to mach or mate with your original setting. I guess it's like this. In a asparated engine you may change the jetting for better fuel delivery. To accomodate for this you will have to adjust the needle valves to match the fuel flow desired. On the Cummins, do you start with the power adj or something else and adjust to the original change with the other adjustments. Do you get what I am trying to say? I realize all this stuff is inter related. How do you know when I have all the adjustments adjusted in tune with each other?

That being said if I change my goal to low end power I should start with a particular adjustment and adjust the others to be in tune with the original adj.

Alec

Gary --

Benchmarks for your truck with a 21cm housing, and a pre-turbo pyrometer:

1500 rpm, long pull at WOT, 4 psi, very little smoke, 11-1200 EGT, may have to control EGT's with accelerator.

If you are blowing too much smoke at 4psi, you probably need to back out the smoke screw, or increase the tension on your AFC spring. If you can't make those temps & boost (just remember, boost builds really slowly under 1700 rpm with the 21) then you need to make sure your AFC is set to the deepest part of the eccentric and, after that, reduce the preload on the spring.

2000 rpm, WOT, 12+ psi, no smoke, 1200 EGT.

2500 rpm, WOT, 15+ psi, no smoke, 1100 EGT.

If after getting the AFC adjusted to make you happy at the lower speeds you want more fuel at these higher rpms, then you can start screwing in the "power screw" -- though this will then raise the amount of fuel available at all speeds, and you might have to go back and re-adjust your AFC settings.

These benchmarks aren't exact, but just to give you a rough idea of what you could expect.

Pre turbo EGT's can run right up to 1200 +/- for extended periods.

At a given speed, EGT's will determine your manifold pressure. As manifold pressure goes up for a given speed, however, it reduces EGT's, so there is a balance there. The EGT's and commensurate pressures that you have posted are what make me think you have some sort of intake or exhaust problem.

I hope this is a little helpful.

Alec

Lil Dog

There are alot of good points here and ya, it basically comes down to personal preference. Where do you want your power? How do you use the truck? These are the kind of things you already have asked but it determines the settings you adjust for.

If you tow alot, you probably don't care about the Peak HP at 2600 RPM, you want more mid range power for good shifts and long pulls on the hills,typically around 2000 - 2400 RPM.

This is where I think the adjustments in the order that aslitch spec is a good approach.

(On the aside..After some discussions I have blown huge holes in my theory from before.. It doesn't make sence to have more boost with increased timing. I should remember that from when I had the pump timing set, I dropped 4 psi just by advancing the timing back to factory specs. :)

Unfortunately I can't offer any bench mark numbers with a 21 cm housing...I have only had this 18 housing, so the low end boost numbers are a little higher. You should be able to attain those baseline numbers, if not, then you may have some other intake or exhaust related problem.

J-eh