AJM Measurements: Are They OK?

HI!
Today, I took my "new" Variant (engine code: AJM, 1.9 TDI, 85 kW) out for some test drives using VCDS (formerly VAG-COM), and I found some of the measured values to be unusual.

1. (see the first graphic, speed-torque).

I started the measurement here in 3rd gear, at idle.
Then I floored it until 5000 rpm. (The orange curve represents the engine speed, and the light blue curve represents the torque.)
First, something seems odd: my maximum torque is around 320 Nm, but according to the literature, the AJM engine should only have "about" 285 Nm, right?
If I calculate the power using the formula P = M * n * 2 * pi (where M is torque in Nm and n is speed in 1/s), I get a value of approximately 107 kW at around 5000 rpm. However, the AJM engine only has a power output of 85 kW.
Are these both measurement errors? (Or is the chip used/recycled?)
I've conducted several more torque measurements, but the results are always similar when I do the calculations.

2. (see the second graph, which shows the relationship between engine speed, target boost pressure, and actual boost pressure).

Here, I started the measurement while in neutral (3rd gear) at idle.
Then, full throttle was applied until approximately 3000 RPM. (The orange curve represents the engine speed, the green curve represents the actual boost pressure, and the light blue curve represents the target boost pressure.)
Is the current boost pressure behaving normally?
It's jumping around quite a bit; it briefly goes above the target value, but then it collapses and falls significantly below it.
My Golf has approximately 115,000 kilometers on the odometer and is making very loud, "whining" noises that sound like they are coming from the turbo. However, there is no rattling or similar sounds yet.

Thank you very much.

Best regards,
Christian.


1. graphic: http://www.uni-magdeburg.de/schaper/redzac/torque_3rd_end.pdf
2. graphic: http://www.uni-magdeburg.de/schaper/redzac/ld_3rd.pdf

Hi,

1. The internal losses of the motor are included in the measured Nm values, which means that less power is actually delivered at the crankshaft.
Um auf ein Chiptuning zu schließen, poste besser die Einspritzmengen beim gleichen Fahrversuch (im 3. Gang or higher).

2. Look for signs of "boost overshot" (in the turbocharger pressure), sticking VTG (variable turbine geometry), etc.
The diagram is somewhat difficult to interpret... what is the target pressure? This could also indicate potential chip tuning.

hi

The desired pressure, which is represented by the blue curve, remains relatively constant at 2100 mbar.
I've now read about several AJMs that also exhibit similar behavior (showing "sogag"-like curves). https://community.dieselschrauber.org/en/viewtopic.php?t=8225&highlight=ajm

"When I have time, I'll run another test with different fuel injection amounts, and maybe also adjust the pulse width for the turbocharger."
Is the key ratio (i.e., the percentage value) the one that should be specified, or the one that actually arrives, i.e., the one that is being sent?

Thank you very much.

best regards, christian

redzac wrote:

The target pressure is the blue curve, and it remains relatively constant at 2100 mbar.

... which doesn't look like chip tuning (unless the tuner forgot or didn't find the LD).

Quote:

Is the duty cycle (i.e., the percentage) the value that is set, or the value that actually arrives, i.e., the value that is applied?

This is the PWM voltage that is applied to the solenoid valve. However, the actual feedback variable is the boost pressure (setpoint value, your green curve).