Diagrams of Torque/Power with VCDS/VAG-COM (Articles)

VAG generally only provides the basic specifications for maximum torque and highest power output for its engines. Therefore, obtaining detailed torque and power curves is difficult.
Diagrams of tuners (for original engines) often contain measurement errors, incorrect scale labels, etc., and are therefore not very reliable.

Using the attached Excel sheet and VAG-COM, an approximate torque and power curve, along with a corresponding graph, can be calculated based on the injection quantities for your own (original or tuned) engine. For this, it is necessary to log the quantities as completely as possible over the entire operating range and to enter them together with the engine's paper data into the calculation sheet.

VAG-COM provides several readings for the injection quantity.
The quantity limitations (primarily in the MWB have the following meanings.

-> Driver Request: The throttle position is converted into a desired injection amount depending on the current engine speed.

-> Torque Limiting: Torque limiting based on speed to prevent overloading of the motor and drivetrain.

-> Air mass limitation (Diesel limitation): maximum injection amount that can be burned while complying with emission regulations. It is calculated, among other things, from the LMM signal, which in turn depends on the load pressure, the intake air temperature, the engine speed, and the condition of the LMM, etc.

In automatic transmissions, there are additional limiting parameters in other MBUs.

The lowest of all the limits appears as the current injection amount in further MWB's and is decisive for the actual torque curve of the engine.

VAG-COM rarely provides smooth 100 RPM values. Therefore, for the Excel sheet, the injection amount is taken from the nearest logged RPM value.
If the 100th engine speed range has been significantly exceeded in the log data, the missing injection quantity can be used as an estimated value based on the surrounding data (see also the note in line 12 + 13 of the calculation sheet).

Since you usually want a full load diagram, you should generally log the values at full throttle. Before doing so, it is advisable to check whether full throttle actually corresponds to 100% pedal travel according to VAG-COM. If not, the pedal position sensor must be adjusted.

High gears and steep inclines extend the measurement time, resulting in a finer distribution of measurement values across the RPM range.

In many engines, the torque limit is lowest at full boost pressure, which therefore determines the torque curve. This can be achieved by briefly increasing the throttle in the 2nd or 3rd gear. Estimate the size.
With these engines, you can also measure the full-load injection volumes while the car is stationary by gently pressing the accelerator, so that the (warm!) engine slowly increases from idle to approximately 4500 rpm. "You must also log the limits."
Since the torque limitation only depends on the speed, it appears in the log with its normal values, even though the engine load is low, and these values can then be transferred to the Excel sheet.

Typically, the air mass limit is engaged until the full boost pressure is established, usually in the low-speed range up to around 1500 rpm. To calculate the resulting torque loss compared to the torque limit, you need to log only a full throttle run from approximately 1000 to around 2000 rpm and then enter the lowest limit in the calculation table.
As long as the air mass limitation is effective, the determined torque curve in the corresponding speed range can vary depending on environmental conditions (air temperature, pressure, etc.).

If, despite normal ambient conditions (temperature, air pressure / altitude above sea level), the air mass limitation is still the lowest at 2000 rpm, then the following should be checked: the turbocharger system, the intake air mass meter (LMM), the throttle position sensor (LLK), and the intake and exhaust pathways.

Since the torque curve is based on the engine computer's calculations, real changes in engine efficiency (e.g., adjusted ignition timing / camshaft) will not alter the calculated result.
Also, even modifications such as changing the injectors, using "10c tricks," or installing powerboxes do not reflect in the calculated torque values. That is, the logged injection volumes only show the original torque values.

Chip-controlled engines can be treated analogously to serial engines for calculation purposes. If the torque is specified at 1900 rpm and the power at 4000 rpm (as indicated by the tuner), then the torque values for the tuned engine can be calculated.


Further Notes:

1. Die Drehmomenttabellen im DZR basieren ausschließlich auf Daten von ALH, AFN und ASZ, die von den Herstellern angegeben oder protokolliert wurden. Die Angaben für die anderen Motoren zwischen 2000 und 4000 prm stammen aus Diagrammen von Tunern (mit den o.a. (Uncertainties).
Whoever wants to determine the torque profile of other engines using the Excel sheet should please send the table to ubeck13@aol.com so that the DZR tables can be corrected if necessary.

2. @Machine builders and other motor experts:
Please review the calculation methods, in particular with regard to the assumed effectiveness rates (Nm per mg of injected quantity).
The series of values will be interpolated based on the known Nm and mg data at 1900 and 4000 rpm for the other speeds, with
-> at speeds between 1700 and 2300 rpm, the highest efficiency (similar to 1900 rpm)
-> below 1700 rpm, a twice as rapid decrease in efficiency is assumed, compared to the assumed value of 2300 rpm.

Suggestions for better/more realistic calculations and other corrections/additions, please also submit to the above. E-mail address.