Let talk mpg and how timing vs fuel helps

[Me78569]

I see ~18* at that load and rpm.

 

But I am guessing in regards to how the ECM is commanding timing.  It might be on a different scale or something strange.

 

I have read that the vp44 in stock fashion maxes out the timing at high revs.  Marcos posted along time ago someplace that max timing was about 30*

 

I wish I had some documentation on it lol.

[TFaoro]

That just seems excessive.... I would think you'd start getting pre-ignition with the timing that high. I've been wrong before though. 

[Mopar1973Man]

Hand math 11.5 MPG the only way I got that much was to run home with the water tank empty. Typically I get 12-13 MPG with the water tank full. So it's still lacking in MPG. Best MPG yet is 14.1 MPG with the RV with full water tank but that was with the Edge Comp. Quad is still lacking. As for the OBDLink I was going to calibrate on this fill but Bluetooth got hung up and crashed the app. Had no where to pull over so that will have to be redone. Still in all the number reported by the OBDLink is close and not far off. 

[AH64ID]

Michael, do you actually notice a difference with a full/empty water tank? I really don't ever see a change due to trailer weight unless I am over 1K heavier/lighter and then it depends on how many grades I pull and even then we are talking less than a 1/2 mpg, if that. The wind resistance just seems to have so much more of an effect than the weight. (On flat ground my camper pulls harder at 19K GCW than a dump trailer at 26K GCW). 

 

 

I wonder if 18° isn't as precise with a VP as a HPCR, meaning at 18° on a HPCR the injector would open but on a VP isn't that where it starts to build pressure and once pressure is met it pop's and injects? I could see much more than a 250us delay with a VP... but that's just thinking out loud. 

[Me78569]

AH64ID

 

that's sort of what I was thinking.  I am guessing the timing is a lot less exact.  The numbers I am seeing make sense for the data stream, but I dunno.  The way the quad takes in and adjust timing reflects the numbers being right....IE there is no fancy math going on to make the timing advance setting work into the map, it is just the user defined advancement based upon a predefined map of how much to use.  

 

.

 

 

Mike,

 

did you get a chance to update the tune via your phone?  I wouldn't bother trying ot calibrate just yet.  I am running your tune right now nearly smoke free so I know you can run a lot more fuel.  How much is to be found out.  You can use lvl 1 to find your starting point.  Set your power reduction to 100, then set to lvl 1 and see if you get any smoke, if you don't then we need to add fuel above stock ( honestly might need to since your injectors are smaller) If you do see smoke, then we drop the % by 1 and try again until we find a good % to start at.  

 

Once we have a starting point you can build the rest of the tune using the % you found above.  I think Mileage will come up to match the edge.   Then you can start playing with the 3-6 psi area and timing advancement to get MPG where it needs to be.,

 

 

[Mopar1973Man]

Most of all the smoke I see is high rev RPM's above 2,500 with heavy foot. Down low its pretty much smokeless. I drove around Walla Walla a few laps between @Taz place and my RV even with a heavy foot in town it run very strong but the smoke is always high in the RPM band. 

[Me78569]

Issue is we need to know when it starts to smoke offidle so we know where to set the starting point of the tune.  Upper end smoke is due to wiretap and we can deal with that once we figure out your MPG issue.  Different issues.

 

 

I think your issue is %100 that the tune starting point of 95 or 97% is too low.  It doesn't smoke because it is underfueled.  Say it doesn't start to smoke until a starting point of %104, MPG numbers will be low is you start from %97 because you are having to use too much throttle to overcome the low starting %.  

 

We need to find what % it starts smoking at offidle, lvl 1 is useful for this as it takes everything else out of the equation, however lvl 1 will not allow for any fueling over %100 so you might need to test on lvl 2.  

 

I am currently running your tune nearly smoke free so I know you can throw more fuel at the engine off idle.  This will allow for less TPS input to go down the road which will result in higher timing from the ECM.  You would be surpised how fast timing falls from 21 or 22 down to 15 or 16, It happens quick after ~22% throttle

[Me78569]

digging through my internet looking.

http://www.turbodieselregister.com/threads/113710-VP44-Timing/page2

Quote

Quote HoleshotHolset,
 

 

That little valve is the single most important part of the pump to consider when trying to advance the timing electronically. . . it

The valve you're talking about is the fuel metering valve; how much fuel is injected. Has nothing to do with the timing of the VP. 



The dynamic timing of the VP is done rotating the whole plunger assembly inside the distribution head. It has a limit of +/- 30° Crankshaft. 



Aloha,

Ciao,



Marco

 

Quote

How much timing can you give us with your ECM?



Within the limits of the VP, anything. . . 

Hey, I'm controlling the brain of the system!



Doug told me he tried a 20* timing program from you, but blew a headgasket. 



Poor Doug!  I told him it would've been too much timing. He wanted it, he got it, he payed for the damage. . .    





I would like 30 btdc . . . . . . . 



That statement is uhmmm. . . incomplete!?!

You have always to consider that the VP timing is dynamic, it's adjusted to various factors. Rpm, load, intake temp, engine temp. . . 



So, 30° BTDC, WHEN??? 

Just as a side note 30° BTDC is too much. . . . . 



Marco

 

 

From Jdonoghue 

http://www.turbodieselregister.com/threads/190100-Inside-the-ECU/page10

Quote

Taking a peek at timing

I've been working on figuring out the various scales of the things like timing, fuel rate, etc. Some scales have been easy - like engine RPM - that one was using the standard SAE scale found in the J1939 document: to get actual RPM from the actual binary number value, just multiply by . 125. 



So, I'm taking a stab at the vp44 commands. If I apply the standard SAE scale to the timing command, I come up with the following:



1. The range allowed by the ECU software is approx. -6* to +60*

2. Warm engine, idling, I see the number 1440 (hex 5A0). That would work out to be 11. 25*



I don't know if this is right, it's just an 'educated guess' at this point.

 

What he is saying says that my numbers for timing are off, I was reading the string and moving decimal by 2 places as a guess.

 

He is saying -6* = 0 and 60* = 4095 in terms of decimal numbers in the message, which doesn't make sense because I am seeing timing messages of 2400 pretty often, from the ECM, which would be over the 30*

 

So back to the drawing board I suppose, my numbers almost make more sense than his.

 

And more

Quote

The timing advance adjustment is 0 - 9*. There are several tables used to adjust timing:
 

• IAT
• Coolant Temp
• Manifold Pressure

Different tables (for IAT and coolant) are used depending upon load/speed. In some cases, the IAT advance number is added to the coolant temp. advance number. The manifold pressure number is never additive. The software will look at the cold advance (IAT, coolant temp) and the manifold pressure advance, and take the higher of the two values. 



There is also another timing algorithm that is used if the engine has been idling for an extended period with no throttle or vehicle movement. You can see this if you run it for a while, then log the timing - it will be 11*-13* at idle. Let it sit at idle for 10 minutes or so, and you'll see that it is up to around 17*, until you touch the throttle, then it drops back to around 11*-13*. 



The RPM/load numbers that determine which IAT table is used:



Table 1 is always used if the RPM is less than 1500. 

If RPM is greater than 1500, but the load(torque) is >= 309 (some internal scale, 309 is probably less than 25%), Table 1 is used. 

Table 2 is only used if RPM is greater than 1500 and the load(torque) is less than 309.

 

 

Quote

More timing information

I've been driving around with the laptop quite a bit, and have figured out some more stuff related to timing. 



First, a correction: the timing adjustment looked like it set a base value of 512, which equals a 0* advance. This is wrong - it only does that when in a certain mode (possibly the 3-cylinder idle mode). Normal operation I never see that flag set - this means it allows adjustment values starting at zero. Remember, anything less than 512 is considered a negative value (retards timing). 



This solves the mystery of the low timing numbers I was seeing on the highway under light to moderate acceleration - what good is less than 12 degrees of timing at 2200 RPM? And more importantly, where was this 'retarded' value coming from?



There were two tables I had labeled 'UNKNOWN 2' and 'UNKNOWN 3' - at first glance, they appeared to be used in the code under cold engine operation. This was not true. They are used all the time, and are what the initial timing adjustment value comes from. It is within these tables I found the magic '-4. 99' value I was seeking. 



Which table is used depends on some unknown condition. If the engine has been in a steady state for a certain amount of time (idling in the driveway for 10 minutes, cruising for 10 minutes on the highway), table 2 is used. Otherwise, table 3 is used. The tables are slightly different. I'm sure I'll figure out exactly how the code decides which table to use. 



More importantly though, is how to take care of this retarded timing issue. I decided to alter both tables, eliminating almost all of the timing retardation. Then I went on a long highway drive for an unscientific test. 



Performance: It seemed to require less throttle to get up the small hills (overpasses, there aren't really any hills around Houston). 



Economy: Tracking actual fuel rate using the laptop, less fuel was used this trip compared to last time (same traffic and weather conditions). Overhead 'lie-o-meter' went from 20. 6 mpg to 21. 2 mpg (really doesn't mean much, but shows an improvement). What I really need to do is go on vacation, then I'll get some real mpg numbers.

 

Quote

The 'calculated SOI' (start-of-injection) number starts from a base table. There are two base tables, and I am not certain what determines which one is used. I do know from observation that what I call the 'B' table is used most often, and I can see it switch to the 'A' table after I've been on the highway for a long time. It switches back to the 'B' table once the engine returns to idle.

So, we start with this value from the 'A' table. This table gets its input from the engine RPM and the load (fueling) number. Notice how 'strange' this table looks:

It is probably like this for emissions reasons. Look at the -4.99 degrees retard in the 2600 RPM column. The load value 1001, as observed on my truck, is part-throttle, for example going up hill on the highway at 70 MPH. Flat land cruise at 70 MPH is usually in the 400 to 500 range.

The value from the 'A' table is taken and compared to several other values:

The light-load advance table (RPM/Manifold pressure)

A value generated from load, RPM, and Intake Air Temperature

The greatest value is taken, and checked to be within range. If it is out of range, it is adjusted.
Now, if the engine is cold, this number will get ignored and a value from a cold engine timing routine will be used instead. This routine uses tables with the coolant temperature and intake air temperature as input.

So, we now have a number somewhere between -9 and +9 degrees. Well, we certainly can't use this number as-is. We'd have a pretty terribly running engine.

This is where another table comes into play. I named this one the 'Base Timing table', but it's apparently called the 'Line Delay table' (what does that mean?), as it's output value can be read using the Chrylser SCI tools and they call it the Line Delay Table. It's inputs are load and engine RPM.

We take the value from this table, and add our +/- 9 degree adjustment to it.

Now, you see how we come up with a 'reasonable' timing number for a diesel engine!

 

Edited September 26, 2016 by Me78569

[TFaoro]

Just read it all Nick..... I'll read it again tomorrow and see if I can comprehend. Some of it is coenciding with Smarty Pro RT, and some of it seems to not be. I'll reply back tomorrow when I have time to digest it. 

[Me78569]

im sitll trying to get through it myself haha.  

 

The more I read the more I think my number is about right.  What I am seeing on the screen matches what the above tables show.

 

Keep in mind the base table may not be in the smarty stuff.  What I see in the smarty stuff is the adjustment tables, but i dunno man too much reading and strange info.

 

As a side note I think I might try a change on the timing map, I am thinking I will try a load index rather than boost.  Load will give a better way to say the truck is at cruise rather than high power.

 

It should allow for more timing at cruise vs what we have right now, without having to guess if we are at cruise or accelerating.

Edited September 26, 2016 by Me78569

[notlimah]

Where'd you pull the info Nick? I had to start 'browsing' through most of that as it seems well above my pay grade! 

[Me78569]

Stuff from the internet people forgot about.

[Mopar1973Man]

I can say that setting the CanBus fueling from 0-5 boost pressure at 100% to 105%. Now the MPG is back to the high mark again. What I'm learning is build the cruise boost pressure area for the highest fuel you can without being stupid smoky. I see some smoke under high throttle but clears rather quickly like the old Edge Comp. Started wrapping my mind around the tune and figure that I had to forget the smoke idea completely. First build your cruise boost pressure for good high fuel values, now I've got the timing back up and MPG's are nice and high again.

[TFaoro]

22 hours ago, Me78569 said:

im sitll trying to get through it myself haha.  

 

The more I read the more I think my number is about right.  What I am seeing on the screen matches what the above tables show.

 

Keep in mind the base table may not be in the smarty stuff.  What I see in the smarty stuff is the adjustment tables, but i dunno man too much reading and strange info.

 

As a side note I think I might try a change on the timing map, I am thinking I will try a load index rather than boost.  Load will give a better way to say the truck is at cruise rather than high power.

 

It should allow for more timing at cruise vs what we have right now, without having to guess if we are at cruise or accelerating.

Regular UDC tuning bases timing off of load and RPM. I like that, but the only issue is you need a different map for every truck then. Each truck spools turbo(s) differently, and that's where having "custom" comes in handy. Idk what could be done in the custom tuning to allow such a feature. That's where you'd have to throw some possible ideas around. Text me if you think anything is possible. 

 

57 minutes ago, Mopar1973Man said:

I can say that setting the CanBus fueling from 0-5 boost pressure at 100% to 105%. Now the MPG is back to the high mark again. What I'm learning is build the cruise boost pressure area for the highest fuel you can without being stupid smoky. I see some smoke under high throttle but clears rather quickly like the old Edge Comp. Started wrapping my mind around the tune and figure that I had to forget the smoke idea completely. First build your cruise boost pressure for good high fuel values, now I've got the timing back up and MPG's are nice and high again.

Interesting.... also makes sense with the smarty S03.... throttle super touchy, so you have to have a light foot all the time. Light foot = higher timing for some reason.....

[Mopar1973Man]

9 hours ago, TFaoro said:

Interesting.... also makes sense with the smarty S03.... throttle super touchy, so you have to have a light foot all the time. Light foot = higher timing for some reason.....

 

 

Just trying the 90% tune of @Me78569 set my cruise control and watch the instant MPG gauge for a few miles. It would produce low teens roughly. Then just set the 0-5 PSI range to 100-105% +1 for each cell. So now do the same thing go out and set the cruise control again and watch for a few miles. Now it dances back and forth through the 30-50 MPG range like it use too. So basically you cannot tune to be smoke free and have MPG at the same time really. Your cruise boost pressure needs to be high in the 100's percent range to get the MPG up.

 

 

[AH64ID]

Light fuel will be higher timing because it's harder to ignite a small amount of fuel so it needs more timing to do so. 

 

If you injected WOT fuel like you did cruise fuel you would be down on power and up on cylinder pressure BTDC. 

 

Seems weird to do most the tuning off of boost. There is a boost fuel limit table for HPCR's but it's just max fuel and not how much fuel is delivered under normal circumstances. 

[Me78569]

What I have found.

 

I had to buy tires yesterday, went with normal highway thread tires.  My timing values are up at cruise by about 1* compared to the old heavy mud tires I had.

 

I can drive now with timing at 20* provided, rpm are under 1500, canbus fuel is under 1100 and tps is under %20

 

More to add later

 

[Mopar1973Man]

I would have to say that is more likely due to less rolling resistance and the rotational mass is maybe down just a few pounds per tire.

[Me78569]

4 hours ago, AH64ID said:

. 

 

Seems weird to do most the tuning off of boost. There is a boost fuel limit table for HPCR's but it's just max fuel and not how much fuel is delivered under normal circumstances. 

Remember we are not tuning based on boost.  We are taking the oem tuning, as it is pretty good, and increasing or decreasing the end result of the oem tune by a % to get rid of smoke or increase power.

 

Mike you should be able to have your cake and eat it too by starting low to keep smoke away then making a 2-4% just at 2 is psi the to your normal % by cruising psi.

[Mopar1973Man]

I'm going to twist the map up.

 

I'm going to try running the low end of the map high as possible. Then the upper end of the map for acceleration build the tune that is smoke free up across the boost. This way I can keep my fuel map at my cruise point nice and high for MPG purpose but acceleration when I'm higher in the map toned down. I'll play with this a bit today too.