I am working on a home made PSG unit and needed to know the min and max absolute timing.

So I improvised a degree wheel and blew back into the #1 port with the pump shaft key way centered

with the mark on the front of the pump by the seal. I could blow back about 30 deg before and 30 deg after

which is +60 and - 60 at the crankshaft.  I noticed that the port starts to close up about 3 degrees sooner

because  of the port hole width. There is also about 1 degree of overlap where two ports are very slightly exposed.

I then measured the rotor, slot and ports then did the math and it confirmed my findings. So never try to inject past ~54 degrees either before or after top dead center.

 

 

o

 

0-30° is the min and max but its not controlled by crank rotation. Its achieved with a separate ring that the high pressure plungers ride on/in.

 

Unless I'm missing the point?

21 minutes ago, Silverwolf2691 said:

0-30° is the min and max but its not controlled by crank rotation. Its achieved with a separate ring that the high pressure plungers ride on/in.

 

Unless I'm missing the point?

That's right the cam ring revolves around the shaft. The timing piston has limits and the software has limits. That phase relationship determines start of injection timing. I need the port alignment timing which is fixed and never changes. If I try to inject when the port is blocked that dead heads the pump plungers and bad things happen. 

Ok gotcha.

 

You are one of two people I've read about who have attempted/are attempting a standalone vp44 control. 

 

This is the other http://www.competitiondiesel.com/forums/showthread.php?t=202024 

He got his to start, but it ran away on him. 

Now I can provide this. The max timing a Quadzilla will provide is 30 degree BTDC. The lowest could possibly be about TDC. 

 

 

Just remember there is 3 parts to the PSG.

 

Fueling, Timing, and Diagnostics. (Error codes, etc.)

@Mopar1973Man, is there anything registering the timing gear's position of the vp44?

 

There was something that I found on competition diesel a while ago with the vp44 and rpms and sled pulling.

 

Some of those members tried advancing the timing gear one tooth clockwise to mechanically advance the injection event, its about 10° advanced. Most abandoned the idea because everyone said that it ran like crap below like 2500 rpm I think, but ran like a bat outta hell above that. And if the non Quadzilla tuners just add on top of factory, you would be at 21+° of timing at an idle, at least on my truck.. I haven't played around with the sliders that much to see what they could pull down too, but IN A RACING SITUATION ONLY, could the Quadzilla pull timing enough to bring the rpm to something reasonable for take off and, at least with a quad 4k I would guess (extra timing sliders), be able to hit like 40° of timing?

 

Sorry for the hijack, I just didn't know if it was worth its own thread to ask that, or what section to put it in..  

10 minutes ago, Silverwolf2691 said:

could the Quadzilla pull timing enough to bring the rpm to something reasonable for take off and, at least with a quad 4k I would guess (extra timing sliders), be able to hit like 40° of timing?

 

Still a max of 30 degrees but more sliders to allow for timing up to 4k. The 30 degree limit is a mechanical limit of the pump period. 

1 minute ago, Mopar1973Man said:

Still a max of 30 degrees but more sliders to allow for timing up to 4k. The 30 degree limit is a mechanical limit of the pump period. 

 

This I agree, but the idea I was mulling around is similar to bumping timing like a p-pump. You still have 30° of adjustable timing, it just becomes 10°-40°.. 

Might be a bit slow launching though...  Too much advancement?

Possibly, for daily driving. That's why I mentioned racing only. I would experiment but I would install a Keating machine cover with the access hole for adjusting the timing of a ppump. But that's a bit rich for my wallet right now. An adjustable timing gear would be interesting too. Only want to add 4° go right ahead lol. 

 

As for the slow launching, possibly, but the original idea was talked about in the sled pulling crowd, no low rpms there.. and I think the Midwest like Lucas Oil Pro Pulling League ppump guys are only in the static 35-40° range ("only" lol), and they are carrying 3500-5000 rpm down the track, depending on the class.

 

@Great work!, could you explain the last photo and your statement of 54° before or after top dead center? I know I kind of took over your thread for a bit but my idea messes with static timing, and you were measuring it. in the photo there are some numbers that I was wondering where you got them. the 6.7 for instance.. [I have to learn to slow down when I'm reading.. I figured most of it out but I'm still interested]       

Edited August 6, 20213 yr by Silverwolf2691

@Silverwolf2691 and @Mopar1973Man Thank You. Collaboration is great! First the 6.7 is just the ratio of rotor slot length in mm 8.9 to the rotor circumference in mm 59.66. So 59.66 / 8.9 = 6.7, the rotor diameter D is 19 mm X π (Pi 3.14) = 59.66 mm. So if the circumference spans 360 degrees then using that same ratio; slot length in degrees = 360/6.7  = 53.7 degrees. 

 

After reading your replies I started digging even deeper with my "degree wheel" and taped the pump shaft to the cam ring. I installed the timing piston and left out the spring and then measured how much range and stroke the timing mechanism has. MoparMan is right I measured 15 degrees (30 crankshaft *) of advance and also noticed that Start of Injection can't really occur after TDC maybe 2* ATDC my measurements are not exact.

Then I made a really big discovery, thanks guys. I noticed the plug part that holds the small servo piston and return spring was actually limiting the stroke of the timing piston by 3 mm. I got almost 20 degrees (40 crankshaft) without the plug. I checked the return spring fully compressed it was 15 mm and the piston depth (inside skirt) for the spring was 18 mm, coincidence I think not. So to get more timing for those sled pullers just machine off 3 mm from the skirt of the piston. I almost bet that a timing piston from a European version V44 from a high performance car (BMW, ***) would allow more advance. The cummins timing piston is 63 mm long. We need someone with a VP44 from a different car to measure one of theirs. Or a Knowledgeable rebuilder / parts person to confirm this. I also thought about machining the plug but 3 mm is a lot and the o-ring groove would be almost gone, but this would have been easier then pulling the pump off.   

 

Next issue is, will the PSG software ignore any timing command over 30* or obey it? If it doesn't like it there is possibly another way around it.

The ECM provides a timing reference signal to the pump on pin 8. This signal  is derived from the crank or cam position sensor. It is has a cycle of 120* an on time of 85* and off time of 35*. The falling edge of this signal happens at 20* ATDC. The VP compares its internal position signal from the sensor on the cam ring to the ECM ref signal to compute its actual timing relationship or phase to the crankshaft then adjusts the mechanism via the TCV solenoid to match the desired value received on the CAN bus. By "tinkering" with the timing ref signal, say advancing it 10* the pump will advance 10* then request 10* less then normal with a tuner on the CAN bus for stock. 

 

The pump may throw an error because it knows approximately  how much duty cycle at the TCV solenoid causes a given amount of advance

after all it can run in some capacity with a bad crank sensor or hot wired in test mode. 

 

Edited August 6, 20213 yr by Great work!
clarity

10 minutes ago, Great work! said:

Next issue is, will the PSG software ignore any timing command over 30* or obey it?

 

It will error out in one way or another. There is software limitations between the ECM and VP44. Quadzilla mention back that we might be able to squeeze 32 degrees but that it. Kind of like trying to extend the fueling you can't because it only fuels to 4095 Decimal (0FFF Hex signed).

 

Truthfully I though a while back if someone could produce a ECM that had the limits removed. Like MAP pressure is limited to 20 PSI. Fueling is limited to 4095, timing again is going ot have a limit. This why all performance box use the priority message to over ride the current data with new data to extend the power. Then beyond that the wire tap will extend 1,200us to 2,200us worth of pulse behind the CanBus signal. If the ECM and PSG were unrestricted you get more. 

 

I will mention I've worked with another member and found a way to make a bigger and badder VP44 pump. I cant remember the cc amounts but it could power 1,000 HP on fuel only easy. It has a requirement of better than 250 HP injectors to keep the pump from choking.

 

No matter what there will be a limitation (software, ECM, etc.) that will prevent you from gaining to much more out of the VP44 pump and ECM. 

Edited August 6, 20213 yr by Mopar1973Man

That's why I want to build my own. My VP transistor went out years ago and I rigged it and its still working amazing. My ECM wait to start gets longer all the time up to 10 seconds now and ECM looses its mind sometimes. I have the ECM split wide open and some CAT5 cables soldered on to the pins so I could spy on everything and not have to stand on my head tapping wires down by the starter. The ECM is just hanging by wires Its amazing it still works.

 

Truth is I built an Arduino PSG  3 years ago and my truck actually ran but rough. The poor Arduino was maxed out, I was trying to do too much with software and soon cooked my fuel solenoid. I actually re-wound it (about 10ft of 25 gauge magnet wire on a bobbin made from a nylon spacer made on my lathe and JB weld) and that worked. Then I snagged the ribbon wire going to the sensor in the pump and ripped it in half. I found out the hard way that these parts must be made of unobtainium and had to buy a reject core for parts. I didn't want to be without my truck so that put things on hold.

10 hours ago, Silverwolf2691 said:

 

This I agree, but the idea I was mulling around is similar to bumping timing like a p-pump. You still have 30° of adjustable timing, it just becomes 10°-40°.. 

Maybe for racing stuff it'll be ok 

Man this is some in depth stuff here!!!

Gosh I wish I knew all this; or what you were even talking about 

 

 

@Great work! How close are you to a functional PSG? After I finish up my PCM I kinda wanna tackle a custom ECU next...

A couple months. I'm on my 3rd generation now, lots of power dissapation, heat issues doing it the Bosch way that's why PSG is on the pump for fuel cooling. Trying switching regulators now but they generate a lot of electrical noise and mask some very weak signals I need. Plus my AC evaporator sprang a leak so it's just too hot to sit in the truck messing with it. We need and ecu alternative to keep these trucks alive they are discontinued.

@Great work!, Any progress on this? I'm curious to know if you stumbled across any more secrets.. 

Well my ECU finally died so its been  slow. I run it hot wired now so it only idles. Timing control is done but the injection solenoid is tricky, it has to have the right recipe of pull in current, holding current and a dead period just before the valve seats. The plunger valve will bounce like a hammer on an anvil and that makes it have a hazy smoke and run rough. The secret recipe has to be adaptive because it changes with battery voltage and fuel duration. Still working it all out. Skipping the CAN bus for now. I just run the TPS MAP and crank sensor into my controller. 

Interesting. Hopefully your new controller does not have the tiny boost to fuel table.

21 minutes ago, Mopar1973Man said:

Interesting. Hopefully your new controller does not have the tiny boost to fuel table.

I was only planning 4 to eight boost table entries. So your saying i need more maybe every 2 psi up to 36 ish.