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I actually use all this theory to adjust MAT tables and it works. I set VE table at around 70Deg.F ambient air temp. I then data log on a very hot day, let's say 94Deg.F (quite hot for here, might not be in Arizona!). I also data log on a cooler day, let's say 32Deg.F. I compare ave INT values and real AFR at WOT, then adjust MAT tables.
It is not very accurate as the MAT tables are restrictive. But it helps a bit, specially at WOT.
Holy cow, that's a lot of great info, thanks! Though in al honesty, I was hoping the answer would be a bit simpler than that... lol. It's going to take me a while to fully understand.
Probably what I'll do is make some changes and log it, then compare the results against this post to help me understand it better.
Though in al honesty, I was hoping the answer would be a bit simpler than that... lol.
LOL, nothing simple about this tuning stuff.
Originally Posted by ULTM8Z
It's going to take me a while to fully understand.
No one does "fully understand" hahaha! I have to read mountains of notes to be able to answer these forums. People, sometime don't realized that. On Facebook, it's terrible the amount of misinformation as people just answer on the fly with their phone while doing something else.
Curious.... (I searched on this but either I missed it or couldn't find it)...
On the Inv MAT table, given how do I know where on the table the ECM is looking for a given MAP and RPM? Given this is a MAP car, it has to be some sort of calculation going on in the background... unless there's a way to get Tunerpro to report out what the ECM is calculating at any given moment?
Curious.... (I searched on this but either I missed it or couldn't find it)...
On the Inv MAT table, given how do I know where on the table the ECM is looking for a given MAP and RPM? Given this is a MAP car, it has to be some sort of calculation going on in the background... unless there's a way to get Tunerpro to report out what the ECM is calculating at any given moment?
Using S_AUJP and its ADX file, there is a "Air Flow" data stream available, L006B.
I reviewed my post#50 and realized I had entered wrong formula. Here's the right one:
ECM uses an airflow g/sec calculation based on this formula: (INJ Flow Rate/60/60)*1000/2.20462 = Air Flow in g/sec Cyl. Vol. in ml * 4 * VE% * MAP/Baro * ((Baro*1000)/(287.058*(MAT+273.15)))/1000*RPM/60
Sorry for confusion
EDITED:
Here's the g/sec to CFM conversion formula:
((Air Flow g/sec/RPM*60)/(((Baro*1000)/(287.058*(MAT+273.15)))/1000)*0.0610237441)/1728*RPM
All the information in post#50 are not EXACT. It's a way to estimate the INJ BPW. It will match the ECM's calculation with a certain error margin. The ECM calculates in HEX not Decimal. However, it's accurate enough to help you with tuning and understanding what ecm does.
Hmmm... I'm not seeing it in the export. See above post. I was able to add it and see it on the dashboard, but I don't think it's putting out the right values.
Hmmm... I'm not seeing it in the export. See above post. I was able to add it and see it on the dashboard, but I don't think it's putting out the right values.
Here's a quick mod version of "JP Day Dash" in S_AUJP v6-4a.ADX, just an example. I see it in the export list.
Hmmm... I'm not seeing it in the export. See above post. I was able to add it and see it on the dashboard, but I don't think it's putting out the right values.
Also, why is the formula cyl vol * 4? Shouldn't be cyl vol * 8 for a V8?
Because V8 only fills 4 cylinders per revolution (360*)
Your ADX must be old version our has been modified so AirFlow is not being logged in. I don't know. It works with Version 6 of S_AUJP and S_AUJP_ADX, that's all I can say.
EDITED:
Looks like the AirFlow feature was added in Version 6. So you need S_AUJP BIN version 6 and S_AUJP ADX version 6. Read the attached document
MAP = kPa
BARO = Pa (the 1000 factor does a conversion to kPa?)
MAT = C I see the 273 for converting to Kelvin?
Boy oh boy!!! Kelvin? LOL, I wrote this formula over a decade ago and I don't remember all the ins and outs of it. Again, it's not exact, just a fair estimation to help you with tuning... Just plug the numbers in a spreadsheet
Example with 383cid:
Cyl. Vol. in ml = 784.25
VE% = 41.9%
MAP = 44.7kpa
Baro = 103.0kpa
MAT = 25.4 Deg.C (MAT input)
RPM = 950
Thanks. Yeah I know how to do the bin... just not the ADX. But my current ADX does what I need, so adding in the airflow seems to have worked for now. I'll try it out at some point this weekend.
Where Dave Jones says...(I highlighted in bold the key stuff)
MAT Compensation Counts vs. MAT Table
let's call it "Comp Counts" for short:
1. A lower number in the table gets you more fuel.
2. Comp counts had a larger impact on fuel than Delta Mult.
3. If IMTLU is enabled, the comp counts table value that has the impact, is NOT the table entry that corresponds to the MAT value. It's the next two or three higher temp entries that have the effect! (this might be why it'd been previously posted that Comp Counts has only a minimal effect -- if IMTLU is enabled, and you mess with the table value where you'd expect it to matter, i.e. corresponding to your MAT temp, nothing happens. This was definitely the biggest surprise of the evening. Edit: actually, leirch mentioned it two posts above this one, but I had no clue what he was talking about until now )
Example, when MAT is 4°C, IMTLU enabled, BPW is 2.79 ms.
Go into the Comp Counts table, and change the closest value, which is 8°C. Nothing happens. Matter of fact, change ALL the entries all the way from -16°C to 32°C. Push 'em up to 255, or whatever. No change in BPW! Now change only the table entry for 44°C from the stock value of 84 to 42, and BPW jumps to 3.17 ms, a 12% change! Gonna have to stare at the hac for quite awhile before I understand that one!
4. If IMTLU is disabled, the Comp Counts table value that causes the change, corresponds to the real MAT value. i.e. if MAT is 44°C, and you change the table entry for 44°C, BPW now DOES change. And in this case, chopping the 44°C value in half as above, from 84 to 42, makes for almost the same change in fuel, with BPW increasing 13%.
Is that really the case? That the table entries corresponding to the temperature in question are not the ones you modify?
Where Dave Jones says...(I highlighted in bold the key stuff)
Is that really the case? That the table entries corresponding to the temperature in question are not the ones you modify?
Well yea, because when IMTLU is enabled the MAT value is combined with the CTS value. So it isn't the straight MAT value for the lookup. 1st post of this thread explains it.
See what @RBob said at #76 and all over this thread. I've learned most of my stuff from him.
See what I said in post #50
I think we are running around in circles here lol
So, here's my final post for this. I am a bit tapped out explaining. Peace!
Testing method, was to hold 1000 RPM, 44.5 KPa, 176°F ECT. Also, 10% TPS, and 20 MPH, to stay out of idle.
MAT was varied, used 40.6°F, 110.9°F, and 150.6°F, which equals 5, 44, and 66°C. (I've had odd results from my scantool trying to read temp in °C, so I scan in °F -- sorry for mixing units)
At each MAT, I messed with the Comp Counts, and Delta Mult tables, and Inverse Term Lookup Enable, and observed the change in BPW.
Summarized observations:
Inverse MAT Term Lookup "IMTLU"
1. Disabling IMTLU always resulted in more fuel. = CORRECT, MAT is not being increased by delta CT * Multiplier.
2. At higher MAT temps, the fuel difference was minor.
(e.g. BPW 2.59 vs 2.64 ms at 66°C MAT; a 2% difference) = CORRECT, at higher MAT, Final MAT maxes out by 92Deg.C
3. At lower MAT temps, the difference was much more significant.
(BPW 3.25 vs 2.79 ms at 5°C MAT; a 16% difference) = CORRECT, at lower MAT, Final MAT will vary more
4. Whether or not IMTLU was enabled, had a big deal to do with the other two MAT tables. = Not sure what he means
MAT Compensation Counts vs. MAT Table
let's call it "Comp Counts" for short:
1. A lower number in the table gets you more fuel. = CORRECT, cooler air = more density
2. Comp counts had a larger impact on fuel than Delta Mult. = CORRECT, because point #2 above.
3. If IMTLU is enabled, the comp counts table value that has the impact, is NOT the table entry that corresponds to the MAT value. It's the next two or three higher temp entries that have the effect! (this might be why it'd been previously posted that Comp Counts has only a minimal effect -- if IMTLU is enabled, and you mess with the table value where you'd expect it to matter, i.e. corresponding to your MAT temp, nothing happens. This was definitely the biggest surprise of the evening. Edit: actually, leirch mentioned it two posts above this one, but I had no clue what he was talking about until now [img]file:///C:/Users/sbcom/AppData/Local/Temp/msohtmlclip1/01/clip_image001.gif[/img]) = WRONG conclusion
Example, when MAT is 4°C, IMTLU enabled, BPW is 2.79 ms.
Go into the Comp Counts table, and change the closest value, which is 8°C. Nothing happens. Matter of fact, change ALL the entries all the way from -16°C to 32°C. Push 'em up to 255, or whatever. No change in BPW! Now change only the table entry for 44°C from the stock value of 84 to 42, and BPW jumps to 3.17 ms, a 12% change! Gonna have to stare at the hac for quite awhile before I understand that one! = CORRECT, because in his example he is using 4°C to look up in “comp counts table”, However, like explained before (post#50), the MAT input is converted to adjusted MAT when “IMTLU” is enabled. MAT input +((CT-MAT)*Multiplier). So depending on how many g/s of air flow he had during his test, MAT adjusted could have been at 44°C, i.e: 4°C + ((80°C-4°C)*.526) = 44°C.
4. If IMTLU is disabled, the Comp Counts table value that causes the change, corresponds to the real MAT value. i.e. if MAT is 44°C, and you change the table entry for 44°C, BPW now DOES change. And in this case, chopping the 44°C value in half as above, from 84 to 42, makes for almost the same change in fuel, with BPW increasing 13%. = CORRECT, because MAT input is not adjusted and used to look up “Comp Counts table”
Ok, I just made a very interesting discovery playing around with this stuff...
For the Miniram, it turned out that the DA3 AE tables transfer over pretty much perfectly. Just some very minor tweaks here and there to dial back on delta MAP AE a bit.
So I thought, just for kicks I wonder what would happen if I used the DA3 MAT compensation count table, Inv MAT table, and VE tables? I figured they all have to work together on the factory LT1s. So I swapped them all into my calibration verbatim and then moved the air temp sensor to just in front of the throttle body for a more factory representative location (I'm running the open element LT1 MAT sensor too).
I'll be damned... BLMs ranging from 132 to 126 all over, right off the bat with all those factory tables. I couldn't believe it!
It took a very long time to get to that point with custom tables, dataloging, analyzing, etc....with the air sensor in the air filter (which is under the batter tray). I'm kicking myself hard for not doing this sooner...
There are a couple of small flat spots in the fueling as I'm watching the WB gauge, (probably need to put back some of that AE Delta MAP I took out earlier). But yeah... damn, I'm dumbfounded by how close this is with just the factory tables.
I'm probably going to leave it like this now and use this as the new baseline. I like being closer to the factory...
This also bodes very well for guys swapping over to short runner manifolds I think...For the initial cut at the calibration, just copy over everything verbatim from DA3 LT1. Soooooo much work gets saved by just being able to copy and past so much of the DA3 LT1 tables... take advantage of all the existing R&D that GM already put into it.
The DA3 LT1 VE tables are definitely the best starting point for a Miniram car. Putting the delta MAP tables back to stock DA3 did the trick on covering the flat spots.
It runs as good now as it did before, but I think it's way cooler that you can literally transcribe the factory calibration from another car and have it essentially run perfectly... leveraging GM's R&D as opposed to spending so much time and effort trying to retune an 8D AUJP based calibration.
I even put the DA3 power enrichment tables in today and they work very well stock too. Though in typical GM fashion a tad on the rich side... was getting close to 11.5:1. Slightly leaned out to get back to about 12.5 and it runs very well.
03-25-2023, 09:59 AM
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