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I'd like to use this thread as a repository of information/theory/etc related to the tuning of our cars. Tuning platform agnostic. All data is welcomed My background is with full standalones (AEM, mostly). This is my first time tuning a car with a torque based boost control strategy. I've been diving in to the OpenFlash stage 1 binary/definition file. I'm looking at the tables responsible for Sport mode. The 'Activation time for overboost' and 'Maximum time for torque boost due to overboost' use seconds as a control metric. I know Cobb OTS maps (possibly others) typically raise this from the default (10 seconds) to 30 seconds (or more). I'm curious if there is a limit? Does anyone use this feature as a simple map selector of sorts?
Request for info: what are the standard axis for the Target Cylinder Filling table? OpenFlash seems to use table/parameter names that don't necessarily correspond to the documentation I've been using (albeit, Cobb may be using non-standard names as well: https://cobbtuning.atlassian.net/wik...BoostControl.5 ). OpenFlash calls the Target Cylinder Filling Table the 'Desired Charge' table fwiw. Definitely a learning curve with regard to Porsche tuning as there doesn't seem to be much info out there. Thus far, the car has been running well though. Will follow up with some log info as well. I've noticed that many of the (torque) limiters have been increased, ostensibly to ease tuning. Making slow changes to the Optimal Engine Torque/Target Cylinder Filling(Desired Charge) tables as part of a judicious boost increase strategy.
From Cobb documentation:
Optimum Engine Torque
Table Description- This is one of the main maps for the torque control strategy. It is used in maximum torque efficiency calculation as well. This value works directly with the map, Target Cylinder Filling.
Tuning Tips- This table needs to be increased if you want to increase boost pressure. Because the ECU works on a torque based boost control strategy, raising this table will also raise boost pressure, as long as the Target Cylinder Filling map is raised as well. You want to try and make a linear change to both tables to ensure that the car runs correctly.
Precautions and Warnings – None at this time
Target Cylinder Filling
Table Description- This table dictates the target load value. Raising this table generally requires the Optimum Engine Torque map to be raised as well. Otherwise a conflict with the torque control strategy will arise and the car will try and apply torque error correction. This table is one of the key proponents to increasing power. Increasing this table has a direct effect on increased boost pressure. Generally speaking, as target cylinder filling increases then more boost pressure is required.
Tuning Tips- Raise this value if you want to increase power, as this table has a direct correlation with the target torque strategy.
Precautions and Warnings – Be sure not to go too high without making appropriate changes to other limit tables, or else the car will run into errors.
Had to break out the German translator for verification haha
The following are all of the tables exposed in TunerPro when using the xdf (definition file) from OpenFlash
Looking at the relationship between the Optimal Engine Torque and Target Cylinder Filling tables: what accounts for the difference between the relative load (x axis in the Target Cylinder Filling (Desired Charge)) and the corresponding value in the Optimal Engine Torque table. For example, at 7000 rpm and 76 load percentage, the value is 177.64. If you look at 7000 rpm and 177.64 (y axis) in the Optimal Engine Torque table, the value is in the 80s.
Confirmation that the COBB 3 bar map sensor is a BOSCH 3 bar (0281006076). The following is from COBB documentation:
Gradient for Pressure Sensor Before ThrottleTable Description – This is the PUT(Pressure Up Throttle) sensor gradient. This needs to be changed if using a larger than stock map sensor. Consult the MAP sensor manufacturer for the values to be put in this table.
Tuning Tips – If you are using a COBB 3 Bar MAP Sensor set this value at 658.83 hpa/v.
Precautions and Warnings – None at this time.
The definition file that I'm using has that table value in kilopascals (253kpa (~22psi + atmospheric)) using the factory 2.5 bar map sensor. The COBB value is in hectopascals per volt. Typical 5v sensors have an operating range of about 4.6 volts. 658.83 hpa/v is 65.883 kpa/v. Multiply the aforementioned pressure per volt value by the voltage range value and you get 303 kpa. I am going to contact BOSCH to inquire about a spec sheet. I haven't been able to find one thus far for this particular sensor. Also reaching out to OpenFlash to determine the factory map sensor offset value.
Offset for Pressure Sensor Before Throttle
Table Description – This is the map sensor offset. Change this value if using larger than stock MAP sensor. Consult the MAP sensor manufacturer for the values to be put in this table.
Tuning Tips – If you are using a COBB 3 Bar MAP Sensor set this value at -63.59hpa or -.92psi depending on the units selected in ATR/ATP.
Precautions and Warnings – None at this time.
Update from Bosch: They relayed a voltage range of 4.5 (0.25-4.75). So 296.4735 kpa.
I’m eager to dive into understanding the structure of the maps and program using Tuner Pro. Could someone please share the XDF definition file for the 997.1 Turbo?
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Tuning Thread
My background is with full standalones (AEM, mostly). This is my first time tuning a car with a torque based boost control strategy. I've been diving in to the OpenFlash stage 1 binary/definition file. I'm looking at the tables responsible for Sport mode. The 'Activation time for overboost' and 'Maximum time for torque boost due to overboost' use seconds as a control metric. I know Cobb OTS maps (possibly others) typically raise this from the default (10 seconds) to 30 seconds (or more). I'm curious if there is a limit? Does anyone use this feature as a simple map selector of sorts?
