Engine/Transmission (1998.5 - 2002) The Ultimate VP44 Q&A Thread

[Mark_Kendrick]

I don't know the flow rate but they make super mentals look mild



I need to be able to set timing and fueling * based on some sort of algorithm (DUH!!)



What can you do about this?



the limit is the amount of * that are practical to use. I'll get enough injector to match it if I can get aa program that will give me optimum fueling parameters.



I'll see what I can find on flow rates for the injectors. . do you need cc/sec lb/hr or what?

 

[Mark_Kendrick]

I would imagine that the usable # of * would also be determined by rpm and boost. at higher boost levels the cylinder pressures are greatly increased so combustion pressure is reached sooner before tdc.

 

[jstarnes]

The rules of the game are: The ECM is the master ( except maybe for the governed speeds) the FCM is the EXECUTOR.



The VP does what the ECM tells her. Fuel rate and timing are determined by the ECM. Period.

so the fueling boxes just boost the signal from the ecm to the vp44baiscily adding more fuel and tweeking timing???



so you want to change the siginal from the ecm by itself to mimic a box (with out having a box)???



you also want to increse the governed rpm of the engine???



(but if you increse the amount of fuel /per stroke and correct timing to match dont you increse rpm untill the ecm sees a signal that is to high from the tach signal then the engine defuels)correct or incorrect???



so what will faking out the tach signal do for engine rpm (Ive herd of story's from back in the day about truckers wireing up a rehostat into the VSS circut and turning down the voltage to fake the ecm into thinking that the engine wasent turning as fast as it was any thoughts ???



you get in the truck ,turn the key ,the engine starts to turn over, ecm sees a tach signal, adds the correct ammount of fuel based on what its programed to send (via temp,boost,ect) so how can you Fake it into reving higher (or can you )???



thanks Jason

 

[E7mack96]

From my understanding of the fueling boxes that attact to the pump wire, They increase the "dwell" on the coil in the VP44 to give more fuel. I am not sure if this extra dwell is just at the end of the signal, or the beginning too. Maybe this is the difference in the boxes that "change timing" and those that don't.



Wadda ya think??

 

[Diesel Freak]

Re: One more time..

Originally posted by Marco



Sure, reprogramming,adapting, the ECM for those injectors is needed, but also that can be done...



Voila' you'd get a RELIABLE and Powerfull system, without getting all the smoke you're producing today.

BTW, every time your engines smokes ( I mean BIG black smoke)

you're waisting fuel and harm the engines performance.



Marco

How much could you lower smoke output by with the stock HX35 as say 35 PSI of boost?



Are you trying to make the combustion process completely stoichiometric?



What are the problems and benefits for making the Diesel cycle stoichiometric?



What are the drawbacks and benefits of Excess Air in a Diesel Cycle?



What turbo system are you using to supply enough excess air to the engine?

 

[Mark_Kendrick]

Freak

We're negating the turbo by assuming that we will be able to supply enough air.



Not that we can ingnore that aspect but we are concentrating on the vp44 and ecm.



Eventually when we will have to take into account the turbo and the injectors when we get to the point of actually programming an ECM... some are further along this path than others ... but right now I'm concentrating on the understanding of how the ECM and FCM interact and what their roles are.

 

[CUMINNTSTRKN]

mark



i hope those injectors your getting from ats, are better than the ones don had in his truck for mm.



jim

 

[Mark_Kendrick]

I have bigger injectors than Don did and a new KwikSpool B1



. . and 6 tires to put it to the ground

 

[TxDieselKid]

Originally posted by Mark_Kendrick

I have bigger injectors than Don did and a new KwikSpool B1



. . and 6 tires to put it to the ground

Mark, you have our "Mr. Amsoil" Don's injectors, not ATS Don right?



Andrew

 

[Mark_Kendrick]

Nope! dramer's the man. He get's them elsewhere. where I dunno but they have lots of holes in them

 

[Diesel Freak]

6 holes?, 8 holes?, what is the part number of the core?



sounds great, as long as they are not like POD injectors with the four . 25mm spray Nozzles

 

[Mark_Kendrick]

I think there's seven. . My wife looked at them for me. I won't get to see them til friday

 

[Marco]

I've written this yesterday, but then I wasn't able to get into the forums... .



I would imagine that the usable # of * would also be determined by rpm and

boost. at higher boost levels the cylinder pressures are greatly increased

so combustion pressure is reached sooner before tdc. "



usable # of * refered to the VP?

No, that remains constant.

Keep in mind that more fuel, burns also slower, the timing needs to be

raised with HUGH injectors. The idle with your injectors sounds like the

timing is retardet ( Softer ). That's due to... .

slower combustion.



"I need to be able to set timing and fueling * based on some sort of

algorithm (DUH!!)



What can you do about this? "



Not much. Not even Cummins/Bosch/DC could do what you're asking for. Those

are values found on empirical basis.



That's because too many variables come into play. The only way to match a

softeware with injectors/turbo is to test them and try...

The Mfr's spend several 1000 hours on the engine dyno to find those values

when they develop a new engine.



For the flow rates of the injectors we use here in milli litre/min

@ 100 bar pressure and fuel temp in the 86-95*F. Also good to know @ which

needle lift

 

[Marco]

Fuelling boxes

There are basically two different types of fuelling boxes.



The "major" fuelling boxes ( the ones that tap into the VP's fuel metering valve wire) add a second injection pulse at the END of the VP's injection stroke.



Think of it as a pilot injection system like the D-Max or the new CR Cummins. Where the "pilot" fuel is the one provided by the ECM

the "main" fuel is provided by the box.



Normally the pilot fuel is a very small amount and is injected arround 30-35° BTDC. The above example is a little missleading because the "pilot" with a box ( aka the ECM's fuel) is the bigger

quantity and injected at the ECM's timing. The "main" added by the box is the smaller amount and is injected way to late ( after BTDC). See where the high EGT's with those boxes come from?



The other boxes change the values in the data bus from the ECM to the FCM. In a few, simple, words they do a "mulitplication"

of the values send out from the ECM. Keep in mind that any mulitplication per zero gives always zero...

Ok, maybe I'm keeping it a little too simple, but to make understand everyone...

That's the the biggest limit for those boxes.



MK, the stock injectors have seven holes, so it looks like your injectors are nothing more than a stock injector with bigger holes. Increasing the dimension of the holes beyond a certain level hurts the spray pattern badly = inefficient combustion.



Twins can overcome that in part due to the high combustion chamber pressures they can produce, with a single turbo that's another story.



I don't say that you will not get higher Hp numbers with those, what I'm saying is that you'll produce them inefficiently. You'll waste fuel and produce smoke.



DF sez:

"How much could you lower smoke output by with the stock HX35 as say 35 PSI of boost?"



Do you get smoke @ 35 Psi???? You should NOT.

Efficient combustion does not produce smoke...



Are you trying to make the combustion process completely stoichiometric?



Hey, we're talking about a Diesel engine here. As you should know that kinda engine is a lean burner. No stechiometric stuff here.



What are the problems and benefits for making the Diesel cycle stoichiometric?



That makes no sense...



What are the drawbacks and benefits of Excess Air in a Diesel Cycle?



Benefit is, it's the only way a Diesel engine operates...



What turbo system are you using to supply enough excess air to the engine?



Depends on YOUR engines configuration and what YOU want to do with YOUR engine.



Enough for now.



Marco

 

[Mark_Kendrick]

Good morning Marco. . I'm still at work.



I was thinking of starting with a stock curve and altering it to fit HUGE injectors. . these have 7 rather large holes but should atomize as well as you could expect for the flow.



I don't have flow specs yet.



usable number of * referring to * of injection that are usable for power. too early and you get a detonation or early combustion and very high cylinder pressures or too late and sending extra unburnt fuel out the exhaust or too long in both directions reducing the strength of the flame front in the cylinder effectively flooding the engine.

 

[Diesel Freak]

Re: Fuelling boxes

Originally posted by Marco





Do you get smoke @ 35 Psi???? You should NOT.

Efficient combustion does not produce smoke...

No, my engine does not smoke at full boost, however I have seen some that do, and it is excessive... but they are over 450 rear wheel horsepower.

 

[Mark_Kendrick]

My wife couted the holes . . I'll have to look for myself. I haven't been home since they showed up. I thought the stock ones had 5 but I'm probably wrong.



I'll let you know how they turn out.

 

[Mark_Kendrick]

Originally posted by Diesel Freak





No, my engine does not smoke at full boost, however I have seen some that do, and it is excessive... but they are over 450 rear wheel horsepower.

Mine didn't smoke at 450hp. . just a grey haze, but I get a goot bit of air in the motor



It oughta smoke like a freight train by saturday morning

 

[Marco]

MK do you ever sleep???

Good Morning,



Let me know how many holes are in those injectors!



No, my engine does not smoke at full boost, however I have seen some that do, and it is excessive... but they are over 450 rear wheel horsepower.



Well, I'm arround that number for daily driving. My set of injectors and the ECM ( plus our fuel) barely smokes at all. By 8-10 Psi no more smoke. Had it smog tested, opacity 8% Oo.





It oughta smoke like a freight train by saturday morning



Yep, I think so, but I also think that the 650 Hp limit on #2 only you've mentioned earlyer is strongly related to the inefficient combustion we're able to get today.



Marco

 

[Mark_Kendrick]

I'm going on an 18 hr day and no end in site.



I'm thinking of having some injectors made with stocke sized holes but twice as many of them at offset angles.



Inefficient combustion huh? you mean a 1/2" deep pool of diesel in the piston won't burn? so much for that garden hose injector idea