That's weird mine will not do that, maybe I will try lowering from stock B0797 and see if I get the same problem.
LMM Lambda and Boost
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That's weird mine will not do that, maybe I will try lowering from stock B0797 and see if I get the same problem.
That table is not a multiplier table. It modifies fuel quantity to make lambda equal to what the table is requesting for lambda based on MAF sensor readings. Like I said earlier, there are several factors that can skew that table. The values that work for one tune may or may not work well for another depending on how everything compares from tune to tune and truck to truck. Keep in mind that smaller numbers in that table will result in more fuel and larger numbers will be less fuel.
My thought came from this thread where it was discussed
https://forum.efilive.com/showthread.php?9368-LBZ-equivalent-of-B0751-B0752/page7
I'll confess I don't fully understand how the ecm uses these table or calculates fuel off of them. So I am trying out different values and seeing how the truck reacts and do some logging to see if I can learn from it.
I appreciate all the help so far
https://forum.efilive.com/showthread.php?9368-LBZ-equivalent-of-B0751-B0752/page7
I'll confess I don't fully understand how the ecm uses these table or calculates fuel off of them. So I am trying out different values and seeing how the truck reacts and do some logging to see if I can learn from it.
I appreciate all the help so far
I'm not trying to be argumentative or talk down to you, but I'm not guessing how that table works. It is a fuel limiting table that limits fuel based on MAF sensor readings. I know for a fact it doesn't work by adding air via vane control because the table works on my both my LBZ and LMM with fixed geometry turbos. You will have to play with the values to find which ones work best for your tune and truck setup. Like I said earlier, larger numbers will make it fuel more conservatively, and smaller numbers will allow it to fuel more aggressively.
No, you are right. I am not sure where I got that idea. I think I read someone elses description and was led to believe it was somehow controlling boost.
I think if anything it may indirectly control boost by the amount of fuel injected and exhaust temp, that's about it
I currently like my boost tables they way I have them so I will concentrate on spooling and smoke output via the B0795 table for now
I think if anything it may indirectly control boost by the amount of fuel injected and exhaust temp, that's about it
I currently like my boost tables they way I have them so I will concentrate on spooling and smoke output via the B0795 table for now
I tested out some more numbers today in the B0795 table.
Sure enough, when I have anything at zero or less (I haven't confirmed all negative numbers yet) it will cut fuel. Even it I set the cells to something real close to zero like 0.001.
0.1 works though. So that is what I am using in the upper air flow cells for now.
I also have the rpm enabler set at the stock value of 6000 so I know the B0795 table works without it being lowered
Sure enough, when I have anything at zero or less (I haven't confirmed all negative numbers yet) it will cut fuel. Even it I set the cells to something real close to zero like 0.001.
0.1 works though. So that is what I am using in the upper air flow cells for now.
I also have the rpm enabler set at the stock value of 6000 so I know the B0795 table works without it being lowered
bumping this back up for a little more info
I took a trip up the mountains on the 1st up to 8000 feet. the truck definitely ran better than the last time I went up. last time it was only 6000 ft. but it still struggled going up the grades at more than about 55 mph.
I wish I had taken some logs of air per cylinder, boost and MAF readings. then I would have much more information on where to make the adjustments to B0795 main injection mixture limits. but I was with some family and didn't have the opportunity.
it also ran very quiet. almost like a gas engine and I was able to hear the turbo over the engine whereas at low altitude with any amount of decent throttle it is all engine noise, very little turbo to be heard. I think I can bump the timing up a little more for medium and high altitudes.
I was thinking if anyone else had any logs of "Air per cylinder", MAF, RPM and boost I could probably get enough data out of it to see where I may need to make adjustments to mine.
I know it won't directly translate, but stock for stock at the same altitude and boost I would think it would be close enough.
I took a trip up the mountains on the 1st up to 8000 feet. the truck definitely ran better than the last time I went up. last time it was only 6000 ft. but it still struggled going up the grades at more than about 55 mph.
I wish I had taken some logs of air per cylinder, boost and MAF readings. then I would have much more information on where to make the adjustments to B0795 main injection mixture limits. but I was with some family and didn't have the opportunity.
it also ran very quiet. almost like a gas engine and I was able to hear the turbo over the engine whereas at low altitude with any amount of decent throttle it is all engine noise, very little turbo to be heard. I think I can bump the timing up a little more for medium and high altitudes.
I was thinking if anyone else had any logs of "Air per cylinder", MAF, RPM and boost I could probably get enough data out of it to see where I may need to make adjustments to mine.
I know it won't directly translate, but stock for stock at the same altitude and boost I would think it would be close enough.
I'm not sure I understand what your end goal is with that table? Or what info it is going to give you to point you in a given direction? I view it as a preboost table kind of deal. After you reach 8psi+, it seems that table is kind of done having its effect. Plus when it is in effect, it's just limiting mm3.
I was hoping to be able to see something like, x altitude at x boost = x lbs of air per cylinder
That way I can see approximately where my truck may have been running. Then I can tweak the table and give it a little more fuel where needed. Right now it is limiting the fuel too much at altitude and making it run poorly
It's going to be a while before I can get to any high altitude to log it.
I was hoping someone else had a log of these pids to kind of guess where I need to make the high altitude adjustments before I head up again. I usually only go about once or twice a year to the upper elevations so logging and adjusting will take a very long time if I do it that way
If you know the area, look up the average baro in the region you are referring to, and compare in the altitude stuff in the airflow section so you know where to make adjustments. That would be enough to get a close stab at it.
That doesn't tell me how much air per cylinder I have (B0795). Unless someone made a fancy spreadsheet to convert it over from baro and boost
If you can find a log showing maf gps at high alt couldn't you use the formula from the calc.cylair pid of {SAE.MAF.gps}*15/{SAE.RPM}? Would be more time consuming then finding a log with the info already but it's a possible option.
I'm going to look through my logs and see if I have any with the appropriate information for do as you suggest.
I honestly feel you're overthinking the air per cylinder deal a bit. Maybe I feel this way because I cant see how I would use that info to make adjustments to either timing or boost if that makes sense?
I think if I was in your situation, and wanted more power without adding alot more risk, maybe raise rail pressure? Take your high alt fuel pressure table, and instead of maxing out at 180mpa, raise it to 190mpa or even 200mpa.
Just a thought maybe? Not trying to say you arent onto something, but my small brain is having a hard time understanding what you're looking for LOL.
I think if I was in your situation, and wanted more power without adding alot more risk, maybe raise rail pressure? Take your high alt fuel pressure table, and instead of maxing out at 180mpa, raise it to 190mpa or even 200mpa.
Just a thought maybe? Not trying to say you arent onto something, but my small brain is having a hard time understanding what you're looking for LOL.
Not trying to raise timing or boost. Only change table B0795 so as to not limit the fuel as much at high altitude without making it smoky at low altitude
If that's the case set b0795 for high alt, and tweak your tunes to help smoke output. Thinking about this, I would think the ecm would be able to do its calculations so alt doesnt effect how b0795 operates etc, but I dont have enough high alt experience to know. Hopefully you find something
I would still be in the same boat but with a different set of tables. Not having any logs showing where it operates when at high altitude limits what I can do.
That is the idea in theory but the ecm does it calculations from the information in the tables. So if the tables says to pull x amount of fuel at x altitude it will do it regardless of what it says for low altitude. The issue is we dont have a separate B0795 table for different altitudes so we need to make one table wotk for all.
As I sit right now, it runs really well at low altitude with very little smoke. But somewhere else in the table it is telling the ecm to only allow x amount when I'm at higher elevation. This is the part of the table I'm struggling with. Without any logs I don't know where it is. If I lower the wrong area or the whole table to inject more fuel then I would have to rework a bunch of tables to fix spool and smoke at it may still limit fuel at elevation. I would rather, if possible, just tweak the one table