spen
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« Reply #15 on: November 06, 2010, 02:03:06 AM »
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Some of the TDi engines can read higher than 2550, but the maps are still scaled up to 2550. I don't know if this extends to other variants, including 1.8t. It is very frustrating. You shouldn't remove control of the boost from the ecu, it's a key function, yet it can't control it very well above 2550mbar  As already stated it would be quite a task to either rescale the scales for every map / constant so that there was a factor between the byte and the actual pressure. Or even harder cast that byte to int16 throughout the code! |
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nyet
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« Reply #16 on: January 18, 2011, 01:57:16 AM »
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The main problem with the S4 ME7 is that almost all maps in the ECU use the 8bit boost pressure variable which has a limit of 2550mbar.
I don't see this is a problem. We were doing the same thing with unscaled MAFs for a very long time, with very few side effects from "low" load... and EVERYTHING is based on load! From what I can tell, there are only a few maps that use the MAP 1) PID (duh) 2) relative pressure max are the obvious ones. I dont know enough about ME7.1 to know if it is used elsewhere. The only other thing I can think of is perhaps comparing it with the ambient sensor on start up .. maybe it throws a dtc if there is a mismatch? Has anybody just tried it? If the ambient thing is a problem, you could probably mess with the offset/slope a bit to put 1 bar from (say) a 3 bar MAP to match 1 bar from the stock MAP (not sure what the effect would be on the top end, i'd have to think on it), and then, like you said, the ecu would just think you are running less pressure than you are. |
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« Last Edit: January 18, 2011, 11:32:39 AM by nyet »
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Tony@NefMoto
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« Reply #17 on: February 04, 2011, 07:48:34 PM »
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The main problem with the S4 ME7 is that almost all maps in the ECU use the 8bit boost pressure variable which has a limit of 2550mbar.
I don't see this is a problem. We were doing the same thing with unscaled MAFs for a very long time, with very few side effects from "low" load... and EVERYTHING is based on load! From what I can tell, there are only a few maps that use the MAP 1) PID (duh) 2) relative pressure max Aside from these two maps, there are also a number of maps that predict the change in load based on the change in intake pressures. That is the only other system I can think of that relies on pressure. I am really against underscaling load. It is possible to make it work of course. But underscaling load has a number of side effects: -Your data logs are all off and can't be directly compared to regular cars -You have effectively disabled all of the high load protection systems in the car If you are willing to rescale all of the maps in the car that deal with component protection to now enable protection at lower loads, then you can run with underscaled load and not have issues. |
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« Last Edit: February 05, 2011, 03:12:34 PM by Tony@NefMoto »
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nyet
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« Reply #18 on: February 05, 2011, 12:26:43 AM »
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there are also a number of maps that predict the change in load based on the change in intake pressures. That is the only other system I can think of that relies on pressure. Any idea if being off a bit would be a problem? Say I just use 3 vs 2.5 bar sensor I am really against underscaling load. It is possible to make it work of course. But underscaling load has a number of side effects:
-Your data logs are all off and can't be directly compared to regular cars
-You had effectively disabled all of the high load protection systems in the car
If you are willing to rescale all of the maps in the car that deal with component protection to now enable protection at lower loads, then you can run with underscaled load and not have issues.
Agreed. Just saying, it was done with load, and load is a MUCH bigger deal than MAP |
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Tony@NefMoto
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« Reply #19 on: February 05, 2011, 03:37:43 PM »
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Any idea if being off a bit would be a problem? Say I just use 3 vs 2.5 bar sensor
It may cause some problems with the ECU predicting the "slow path" load changes. I would think this would cause the ECU to undershoot or overshoot it's load control. |
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nyet
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« Reply #20 on: March 06, 2011, 04:01:22 PM »
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It may cause some problems with the ECU predicting the "slow path" load changes. I would think this would cause the ECU to undershoot or overshoot it's load control.
Perhaps there are maps in ME that can be tweaked to compensate? |
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Tony@NefMoto
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« Reply #21 on: March 08, 2011, 02:30:37 PM »
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Perhaps there are maps in ME that can be tweaked to compensate?
There are maps that convert manifold pressure into cylinder pressure and into turbo pressure. I assume those could be used to adjust the slow path calculations when using an underscaled MAP. |
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nyet
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« Reply #22 on: March 08, 2011, 03:06:02 PM »
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There are maps that convert manifold pressure into cylinder pressure and into turbo pressure.
Know any IDs off hand?  |
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Tony@NefMoto
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« Reply #23 on: May 10, 2011, 01:02:49 PM »
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There are maps that convert manifold pressure into cylinder pressure and into turbo pressure.
Know any IDs off hand? Here is some of the definitions of the relevant maps I have in my old map editor software. There are addresses from the MBox 0002 bin file. "TwoDConsecutiveIntervalMap" means the map format is: height, width, height lookup table, width lookup table, height x width map table data. TwoDConsecutiveIntervalMap("Correction Factor for going from intake pressure to cylinder pressure during max camshaft advance", 0x81BC16, UINT16, 1.0 / 32768.0, 0.0, "Factor", "", OneDimensionalMap(engineSpeedVar_UInt16_F87A), OneDimensionalMap(loadVar_UInt16_F990)));//10x10 TwoDConsecutiveIntervalMap("Correction Factor for going from intake pressure to cylinder pressure during min camshaft advance", 0x81BB22, UINT16, 1.0 / 32768.0, 0.0, "Factor", "", OneDimensionalMap(engineSpeedVar_UInt16_F87A), OneDimensionalMap(loadVar_UInt16_F990)));//10x10 TwoDConsecutiveIntervalMap("Conversion factor from pressure to load", 0x81BDA6, UINT16, 1.0 / 219545.6, 0.0, "Factor", "%/mbar", OneDimensionalMap(engineSpeedVar_UInt16_F87A), OneDimensionalMap(camshaftOverlapAngleVar_UInt16_3822E8))); TwoDConsecutiveIntervalMap("Internal Exhaust Gas Partial Pressure", 0x81BD0A, UINT16, 1.0 / 25.6, 0.0, "Pressure", "mbar", OneDimensionalMap(camshaftOverlapAngleVar_UInt16_3822E8), OneDimensionalMap(engineSpeedVar_UInt16_F87A))); |
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« Last Edit: May 10, 2011, 07:05:43 PM by Tony@NefMoto »
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nyet
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« Reply #24 on: May 10, 2011, 06:48:03 PM »
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Thanks Tony.
Are you pretty sure all of those are used for more than just speed/density?
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Tony@NefMoto
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« Reply #25 on: May 10, 2011, 07:04:11 PM »
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Are you pretty sure all of those are used for more than just speed/density?
From what I recall, they are used to predict the change in load based on the change in pressure. It is used by the "slow path" torque demand system to predict how the load will change. The "slow path" uses these maps to determine if it needs raise or lower the boost pressure to meet the desired load. When I release my data logger, you will be able to log the variables showing the ECUs expected load change based on the pressure change. |
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nyet
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« Reply #26 on: May 10, 2011, 07:16:50 PM »
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The "slow path" uses these maps to determine if it needs raise or lower the boost pressure to meet the desired load.
Interesting; i did a scatter plot of req load vs req boost and i dont see much variance depending on current MAP... would definitely be nice to have more data to log to see how req boost varies with a given req load. I never did understand that calculation.... |
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nyet
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« Reply #27 on: May 12, 2011, 09:42:54 AM »
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As far as I can tell, these are all in my map packs already: TwoDConsecutiveIntervalMap("Correction Factor for going from intake pressure to cylinder pressure during max camshaft advance", 0x81BC16, UINT16, 1.0 / 32768.0, 0.0, "Factor", "", OneDimensionalMap(engineSpeedVar_UInt16_F87A), OneDimensionalMap(loadVar_UInt16_F990)));//10x10
This appears to be KFPBRNW at 1BC42. Its axis data starts at 1BC1A, not 1BC16 though, unless I got something wrong TwoDConsecutiveIntervalMap("Correction Factor for going from intake pressure to cylinder pressure during min camshaft advance", 0x81BB22, UINT16, 1.0 / 32768.0, 0.0, "Factor", "", OneDimensionalMap(engineSpeedVar_UInt16_F87A), OneDimensionalMap(loadVar_UInt16_F990)));//10x10
KFPBRK TwoDConsecutiveIntervalMap("Conversion factor from pressure to load", 0x81BDA6, UINT16, 1.0 / 219545.6, 0.0, "Factor", "%/mbar", OneDimensionalMap(engineSpeedVar_UInt16_F87A), OneDimensionalMap(camshaftOverlapAngleVar_UInt16_3822E8)));
KFURL TwoDConsecutiveIntervalMap("Internal Exhaust Gas Partial Pressure", 0x81BD0A, UINT16, 1.0 / 25.6, 0.0, "Pressure", "mbar", OneDimensionalMap(camshaftOverlapAngleVar_UInt16_3822E8), OneDimensionalMap(engineSpeedVar_UInt16_F87A)));
KFPRG |
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Tony@NefMoto
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« Reply #28 on: May 12, 2011, 10:56:24 AM »
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TwoDConsecutiveIntervalMap("Correction Factor for going from intake pressure to cylinder pressure during max camshaft advance", 0x81BC16, UINT16, 1.0 / 32768.0, 0.0, "Factor", "", OneDimensionalMap(engineSpeedVar_UInt16_F87A), OneDimensionalMap(loadVar_UInt16_F990)));//10x10
This appears to be KFPBRNW at 1BC42. Its axis data starts at 1BC1A, not 1BC16 though, unless I got something wrong My definitions says 1BC16 because there are four bytes for the height and width of the map. |
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julex
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« Reply #29 on: May 13, 2011, 11:58:27 AM »
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I looked at it a bit few nights ago and the only "Quick" way would be to run larger MAP sensor (400kpa) from european TDI car. It has the same plug and housing.
It will read underscaled naturally. The Maps Tony listed can be used to make the MAP work as well as couple others dealing with minimum ambient pressure (700mbar), conversion of boost into air mass KVLAD and possibly few others, forget which ones now but WinOLS definition pack has quite a few you can touch.
There interesting one is DSLGRAD "Gradient pressure sensor for charge pressure" with default value of 541.0 hpa (0.541 bar). This is nothing else than scaling for our default sensor, 1v=0.541 bar. If only we didn't have that silly 2559mbar limit we could very easily stick any sensor you wanted in there and easily scale it up.
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