2byte load's
So, I'm guessing that either Mitsu found that above a certain temperature, the temp compensation wasn't necessary since the changes were negligible or they used a simply table lookup because of the change being linear or some simple relationship.
Very interesting results, to say the least. So, when everyone is logging their 2-byte loads, what load are we logging? I want to log the temp+baro compensated load. That is the true mass airflow/rev load.
EDIT: Tephra, I went a reread what Bez posted and he is stating that there is a function that he called GET_LOAD) that should be selecting the temp and baro compensated load for timing and fuel, unless one of the sensors are bad. Are you stating that you are finding something different?
Posting tons of disassembly probably not a good idea here - but I'll try to clear things how it works.
1. Recorded MAF pulses per RPM period value..
2.Some smoothings done.
4.SOme filtering done (the value and the previous value are compared -if the difference too high the newly recoreded value is discarded)
5. The maximum allowed mafperrpm(RPM) got from table and compared to value that got. Trimmed if bigger. The result called MAF_SOURCE_MAIN in my disasms...
6. The first load is got by multiplying MAF_SOURCE_MAIN by mafsize (mafsize is available in ecuflash definitions -its actually engine's size).
Then the all LOADS got ....First is ~MAFHZ/RPM*mafsize.
Second ~MAF/RPM*mafsize*BAROMETR
Final Load ~MAF/RPM*mafsize*BAROMETR *Air_temp_density
Airtemp_density got from table based on MAF air tempetature readings.
In routines that gets timing values from table or fuel the procedure GET_LOAD is used wich selects load according on the sensor's functionality- if all ok the third load is used ....If air temperature sensor is down than the second load is used...
To get MAF_HZ, MAF_SOURCE MAIN is then back multiplied by RPM ..
Then Maf_filtering table is used , them maf smoothing , than maf (scaled and smoothed) is barometr and airtemp compensated and a value Air Mass is got (trimmed available through MUT 28)...
1. Recorded MAF pulses per RPM period value..
2.Some smoothings done.
4.SOme filtering done (the value and the previous value are compared -if the difference too high the newly recoreded value is discarded)
5. The maximum allowed mafperrpm(RPM) got from table and compared to value that got. Trimmed if bigger. The result called MAF_SOURCE_MAIN in my disasms...
6. The first load is got by multiplying MAF_SOURCE_MAIN by mafsize (mafsize is available in ecuflash definitions -its actually engine's size).
Then the all LOADS got ....First is ~MAFHZ/RPM*mafsize.
Second ~MAF/RPM*mafsize*BAROMETR
Final Load ~MAF/RPM*mafsize*BAROMETR *Air_temp_density
Airtemp_density got from table based on MAF air tempetature readings.
In routines that gets timing values from table or fuel the procedure GET_LOAD is used wich selects load according on the sensor's functionality- if all ok the third load is used ....If air temperature sensor is down than the second load is used...
To get MAF_HZ, MAF_SOURCE MAIN is then back multiplied by RPM ..
Then Maf_filtering table is used , them maf smoothing , than maf (scaled and smoothed) is barometr and airtemp compensated and a value Air Mass is got (trimmed available through MUT 28)...
Eric
Last edited by l2r99gst; Nov 16, 2007 at 06:40 AM.
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I've been using the lowest hex value for load (6B12 on my 88570008 IIRC), which explains why it is quite close to boost if it isn't baro or temp compensated...
I was finding it through the boost limit routine.
I was finding it through the boost limit routine.
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Yeah, it looks like tephra is covering the same ground that I did, but now going into more detail. Its interesting to consider whether there is any value to using the same load temp+baro compensated load variable for the fuel/timing/mivec lookups. If you look at one of my logs, the difference in the load values can be different in warmer weather. The difference between load fuel and load timing is still within 10 load units though. Having load timing run at lower values would tend to push the timing up slightly in warmer weather. Not a particularly desirable feature. MIVEC uses the same load variable as boost, so it can be as much as 20 load units different than load fuel. Most people use the same MIVEC settings across a wide load range though, so the large difference between load MIVEC and load fuel is moot.
How bout we pick one load variable and assign it to everything (MIVEC,boost,timing and fuel)???
We would probably wanna use a temp+baro compensated load variable, right???
We would probably wanna use a temp+baro compensated load variable, right???
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EDIT: Tephra, I went a reread what Bez posted and he is stating that there is a function that he called GET_LOAD) that should be selecting the temp and baro compensated load for timing and fuel, unless one of the sensors are bad. Are you stating that you are finding something different?
From memory the timing on does a sensor error check and then in a subroutine from that does an air_intake_temp compare, and then either returns baro_compensated_load or temp+baro_load.
I will try and post up some screens from the disassembly as its hard to explain
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so is a lower air_tempature equal to higher or lower load?
edit - does this makes sense?, for TIMING:
if the air_temp > 65 then return the baro_compensated load
because if air_temp higher then baro+temp_load will be smaller, which in return means timing maps will return LARGER *advance which for hotter weather would be bad.
edit - does this makes sense?, for TIMING:
if the air_temp > 65 then return the baro_compensated load
because if air_temp higher then baro+temp_load will be smaller, which in return means timing maps will return LARGER *advance which for hotter weather would be bad.
Last edited by tephra; Nov 16, 2007 at 05:43 PM.
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i thought about setting all the "loads" the the same thing - but obviously mitsubishi did it for a reason ... so before I make something explode I prefer to do logs and see what the behaviour is first
it will make tuning easier for us thou - have all the same "load"
it will make tuning easier for us thou - have all the same "load"
so is a lower air_tempature equal to higher or lower load?
edit - does this makes sense?, for TIMING:
if the air_temp > 65 then return the baro_compensated load
because if air_temp higher then baro+temp_load will be smaller, which in return means timing maps will return LARGER *advance which for hotter weather would be bad.
edit - does this makes sense?, for TIMING:
if the air_temp > 65 then return the baro_compensated load
because if air_temp higher then baro+temp_load will be smaller, which in return means timing maps will return LARGER *advance which for hotter weather would be bad.
All things being equal, a lower temperature will give a higher load, that is the baro+temp compensated load. I showed this in my 'boost estimate' thread.
Well, yes and no. More timing in hotter weather may be worse. I agree with that. But, the hotter weather causes less mass airflow, thus less cylinder pressure. So, you can add more timing because you're simply not stuffing enough air in the cylinder to create the cylinder pressures that you would get at lower temperatures.
I showed in my other thread that just from a 100*F change in temperature, the same boost will result in a difference of 6 lb/min of airflow. That's roughly 60 HP worth.
Eric
I showed in my other thread that just from a 100*F change in temperature, the same boost will result in a difference of 6 lb/min of airflow. That's roughly 60 HP worth.
Eric
Last edited by l2r99gst; Nov 16, 2007 at 07:30 PM.
Eric
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so as the barometer decreases (altitude increases) the "load" also decreases, which in tern allows you to run more ignition advance?
and thus the ign maps have a higher advance at lower loads...
and thus the ign maps have a higher advance at lower loads...
Last edited by tephra; Nov 16, 2007 at 08:52 PM.
Thats what i was thinking. Hopefully e can find one to use for all the loads.