Once and for all: Do TST boxes have TIMING??

[Marco]

Think about it...

I would add one last thing into this discussion.

OK, some say the timing can be altered tapping the fuel solenoid wire, other say it can't. To each his own...



You might want to consider that not all engines (ECM's) have the same timing! For example, RSnaith mentiones four different test trucks. Well, all of these original softwares use a different timing... . Why that is I dunno but so it is.



What I ask myself is how can a box adjust itself to the different stock timings? ONE FITS ALL????????????



Marco

 

[CRoth - BD-Power]

In theory you might be able to get away with one box producing a timing curve for all of the four engines. It all depends on how the box was engineered.



For an example lets say that the ECM controls timing by a 8 bit number. So you have 256 different timing points going to the VP44. Lets say that all four different trucks output a different timing value at our specific load point. (i. e. 2000RPM, 100% load). ECM#1 = 120, ECM#2 = 124, ECM#3 = 118, ECM#4 = 122. Now depending on how the performance box was engineered it may replace the ECM's timing number with its own. For instance the box would convert the 120,124,118 & 122 that is on the CAN and change it to 128. This way the box should in theory work for all the different ECMs. But if the box was engineered to add or subtract to the timing values Marco is definitely right you would run into problems.

 

[KLockliear]

Originally posted by CRoth - BD-Power

For instance the box would convert the 120,124,118 & 122 that is on the CAN and change it to 128. This way the box should in theory work for all the different ECMs.

There it is though... you have to be on the CAN BUS to do it with direct control.

 

[Briar Hopper]

My actual results on a Dyno Dynamics showed an increase from 463 HP to 501 HP when I stacked a newer VA box with my TST PM3 . Torque went from around 1100 to over 1200, unmeasurable past that, on that dyno. I plugged and unplugged the VA, two runs each, just to make sure.

I'm quoting the 463 HP from memory, I'm away from the shop and my dyno sheets at the moment, sorry. I'll post a correction if necessary, after I review the sheets. Top HP definitely was 501, though.

 

[Marco]

The truth shines through...

Finally!



KLockliear sez:

you have to be on the CAN BUS to do it with direct control



Amen.



CRoth - BD-Power sez:





For an example lets say that the ECM controls timing by a 8 bit number. So you have 256 different timing points going to the VP44. Lets say that all four different trucks output a different timing value at our specific load point. (i. e. 2000RPM, 100% load). ECM#1 = 120, ECM#2 = 124, ECM#3 = 118, ECM#4 = 122. Now depending on how the performance box was engineered it may replace the ECM's timing number with its own. For instance the box would convert the 120,124,118 & 122 that is on the CAN and change it to 128. This way the box should in theory work for all the different ECMs.



The highest value in 8 bit is 255.

So we can send a value from zero to 255 to the VP. ( I'm saying that simply to make it easier to understand. )



In theory an add on box would take over the controll of the timing on it's own.



Well, 95% of the ECM is used for timing calculations. There are MANY variables ( Air temp, Engine temp, boost, Rpm, LOAD... ) that

are taken into account for that calculation.

Most of them are ploted t in the maps to 1/10th of a degree.

A "simple" small box can do it the same or better? Hard to believe! ( For me, to each his own... !)



Another point, I suspect that there are several different versions of the VP out there. Each one needs his specific timing tables to work properly. One box fit's 'em all? Hard to believe...



Briar Hopper tells us about the power increase with an addeed timing module.



Let me tell you this. There is NO WAY a different timing alone would net that much power increase.



The guys @ Cummins ain't stupid, they know better than us how to set up a timing! Sure they have to controll emissions but their timing isn't too much away from the best possible (performance and MPG wise).



Marco

 

[CRoth - BD-Power]

Re: The truth shines through...

Originally posted by Marco

Finally!





Another point, I suspect that there are several different versions of the VP out there. Each one needs his specific timing tables to work properly. One box fit's 'em all? Hard to believe...





Marco

I would agree with this statement but how would the ECM know if a replacement pump(updated version) was installed? Keeping in mind the pumps would both be 235HP specific. ... ... Unless the pumps base timing is communicated back to the ECM.

 

[Hohn]

This is all very interesting. What is meant by "base timing"? Wouldn't timing be controlled by the ECM for whatever pump was installed? Like, if the ECM says fire @ 3°BTDC, wouldn't that command be carried out by both a -028 and a-027 VP44? How does the different pump mean a different response to the ECM commands?



It also seems to confuse me as to why a wire-tap box makes LESS power on an HO pump vs a SO pump. All the lit I have read says that the HO pumps are programmed to deliver more fuel than the SO pumps. IS this done with plunger travel? Pulse width? How?



The reason I mention this is because it would seem that IF the HO pumps are capable of delivering more fuel, then they should make MORE, NOT LESS power, than the SO pumps. Yet we know this to be false!!



Furthermore, is pulse width and timing the only control the ECM has on the pump? I mean, is it impossible to increase fueling (thru the VP) without increasing pulse width? I was under the impression that the only way to increase fuel rate for a given pulse width was larger injectors. Is the fuel pressure in the high-pressure injection lines constant in that sense? IS that what a modified pump does- increase pressure output of the VP?



It remains a great mystery to me how the SO trucks deliver more power with a fueling box when the HO trucks are supposed to have a higher fueling-capability system. Is there some untapped potential in the HO trucks that we are overlooking??



Untapped wire and happy,

Hohn

 

[KLockliear]

I'm not the electronic engineer here (Edge would be best to answer this stuff), but my understanding is that the ECM commands a timing setting, and that is carried out by the computer on top of the pump. We call it the FCM (Fuel Control Module). There is one on each pump...comes with it and is mated for life. You can't swap them from one pump to another.



This is why the box can talk to the ECM on the CAN BUS, to get the response wanted on any pump. The FCM knows what pump it's on and does it accordingly.



The HO pump is NOT capable of delivering more fuel, the SO pump is (of the two). However, the stock program for fueling is more aggressive for the HO truck. What we find though, is that the SO pump responds better to electronic upgrades due to its internal mechanical differences. For clarity, lets look at it like this:



The HO pump and SO pump both have a program to deliver "X" fuel. When a box says deliver "X+20%", that 20% is more fuel on the SO pump then the HO pump based on the internals.

 

[CRoth - BD-Power]

Originally posted by KLockliear

I'm not the electronic engineer here (Edge would be best to answer this stuff), but my understanding is that the ECM commands a timing setting, and that is carried out by the computer on top of the pump. We call it the FCM (Fuel Control Module). There is one on each pump...comes with it and is mated for life. You can't swap them from one pump to another.



This is why the box can talk to the ECM on the CAN BUS, to get the response wanted on any pump. The FCM knows what pump it's on and does it accordingly.



The HO pump is NOT capable of delivering more fuel, the SO pump is (of the two). However, the stock program for fueling is more aggressive for the HO truck. What we find though, is that the SO pump responds better to electronic upgrades due to its internal mechanical differences. For clarity, lets look at it like this:



The HO pump and SO pump both have a program to deliver "X" fuel. When a box says deliver "X+20%", that 20% is more fuel on the SO pump then the HO pump based on the internals.

Keith tell them about the different plungers and offset cam ring too.

 

[KLockliear]

Originally posted by CRoth - BD-Power

Keith tell them about the different plungers and offset cam ring too.

Hey, quit prodding me for info!



Ok, so now that it's out in the open, the plungers in the HO pump are about . 030" smaller diameter than the SO pump, so the SO pump has more volume in it's high pressure section. These plungers (3 of them) move in and out of a bore in a rotating head. They move out based on input fuel pressure, then are pushed back in by a cam ring. The cam ring is an outer ring that has scallops cut out of it. Each scallop is where the plunger moves out to fill, then when it comes to the tight part, that's where the pump makes pressure. There is a solenoid in the pump that moves the cam ring, which is how timing is achieved in the VP44.



The SO and HO pumps have different cam rings with different ramp angles for more/less aggressive plunger travel as well.



And that's all I'm gonna say about the internal workings of a VP44.

 

[Marco]

They move out based on input fuel pressure



C'mon you can do better!



Tell 'em more.



However, the stock program for fueling is more aggressive for the HO truck.



Nope that's not. It's the opposite!

You do not take the higher pressure of the HO into the picture.



The SO and HO pumps have different cam rings with different ramp angles for more/less aggressive plunger travel as well



The HO has the more aggressive cam ring. That translates into the fact that it produces a higher pressure for a given Rpm. Higher pressure = more fuel for the same given time. Also the ECM comands a later opening of the fuel solenoid for the HO.

Again higher pressure...



Marco

 

[Marco]

ETC-ETH fuel maps.

That's the fuel maps for the ETC ( red ) and ETH( blue )

 

[Marco]

Sorry for the poor quality!

I had to take a pic from my monitor and then resize it... .



Anyway, you can see here what the stock fuelling maps look like.

From the left to the right there are the different fuel maps for different loads. Each "point" you see in the maps is used for a different RPM. The higher the points then longer the fuel delivery valve of the VP is opened.



Except for the idle range, the ETC maps are always higher than the ETH's... .



Marco

 

[Hohn]

Now we are getting somewhere!!



So it would seem that the best overall setup would be to mate the HO cam ring (with its more aggressive ramps) to the SO plunger head (with its larger plunger pistons).



Too bad you can't do that, as I am sure all you big HP guys have already thought of that. But why couldn't you machine your own cam ring?



Sounds like the SO and HO motors use different recipes for fuel delivery. Since the variable are volume, pressure, and time, there's more than one way to skin the fuel delivery cat. (sorry for the colloquialism, Marco). The HOs rely more on pressure (via more aggressive cam ring). The SOs rely on the plunger volume.



THIS finally makes sense. This explains perfectly (to me) why the ETH makes more power for a given injector size, and why the ETC gets more out of a box. The ETH flows more fuel through a given orifice size because of its higher pressure. BUT, the smaller plungers mean that a fueling box "tops out" sooner-- the plungers have less fuel reserve to deliver. OTOH, the ETC pumps have more fuel delivery reserve (stored in plungers), but need TIME to deliver that fuel since the less aggressive cam ring won't empty the plungers as fast.



I am thinking out loud here, so please be patient with those of us who have never seen a VP in pieces (in person), or really know how injection pumps work. I saw the VP pics marco posted, but it's hard to REALLY get a grip on something until you take it apart for yourself. That's how *I* learn most things, anyway.



This make the HP numbers that the 24V guys are putting up even more impressive, since the VP will only deliver so much fuel, no matter how long you activate the solenoid. Once the plungers are empty, you're done.



About how far can you go before you max out the stock fuel delivery of the HO VP? I am thinking that a 70% fuel box and BD7's would get you REAL close.....



HOHN

 

[Marco]

The picture is almost complete.

BUT there is another 'lil gizmo in the VP I've never heard any talk about. That's the "membrane chamber" ( I'm translating it from German, dunno how you'd call it in English)



This membrane chamber is in direct communication with the high pressure chamber. Part of the high pressure fuel is "stored" there and then released back into the high pressure chamber between the plungers in way to help to push the plungers outwards when the fuel delivery valve opens.



The fuel in the membrane chamber is what the major fuelling boxes use. These boxes append a second injection pulse after the main (ECM) pulse has been finished. Where does that fuel come from since the plungers have already pumped their fuel? You name it, the membrane chamber.....



Clear as mud?:{



Marco

 

[RustyJC]

Re: The picture is almost complete.

Originally posted by Marco

That's the "membrane chamber" ( I'm translating it from German, dunno how you'd call it in English.

Marco,



Sounds like an accumulator.



Rusty

 

[Hohn]

Marco, you mean that ALL the fuel in the plungers is used up by the primary (ECM) injection event??? How is this? Also, how does this "membrane" allow mroe fuel to be injected?



One would think that ALL fuel that is injected would have to be highly pressurized, and therefore would come from that inner, High-pressure part of the VP. IS there another area of he VP that is also at the same high fuel pressure?



Furthermore, it would seem to me that IF a fueling box utilized this "membrane chamber" then the plunger size would not matter, since the box is getting its fuel from another part of the VP.



The only way I can make sense of this is if this "membrane chamber" follows immediately AFTER the high pressure part of the pump head, so it stores fuel at high pressure. Then, the plunger size becomes relevant again- i. e. how fast can the plungers supply and refill this chamber, etc... .



HOHN

 

[Marco]

The only way I can make sense of this is if this "membrane chamber" follows immediately AFTER the high pressure part of the pump head, so it stores fuel at high pressure



That's what it does. It stores high pressure fuel.



Marco

 

[krabman]

Mark popped in on a thread on the 3rd gen about the cr box somewheres before I went up North last time, that was in January. I would guess he is at least reading the forums from time to time. I cant offer any information or shed any light on this topic being as I dont have the expertise. I can say one thing though. Seat of the pants is pretty important to me as a consumer of these products. I would much rather have power I can feel going through the gears in every day driving than power that can be felt during a 1/4 mile run at max rpm but not during normal driving even though a dyno run tells me I have more overall power. Im not saying there is anything wrong with using a dyno for tuning and checking results just saying that seat of the pants has meaning to me. JMHO

 

[Diesel Freak]

not trying to muddy the waters here, but



run one... injectors (DD3's) Turbo (PDR40), and boost module

Run two. . turned on fueling box

run three... turned off fueling box, and plugged in timing box

run four... piggybacked fueling and timing boxes.



this just gives an idea how the two (fuel, and timing) can affect power



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