30c-Tuning Idea for PD Motors

Hello,

Apparently, PDs (Performance Diesels) can achieve "significantly" more power by tricking the engine computer into believing that the diesel temperature is higher than it actually is.

Here, there was already a "discussion" about a corresponding box that only contains a 180Ohm resistor, which replaces the NTC sensor circuit-wise.
Recently, I also know the reason for this value: the engine computer indicates it as 130°C, which is the highest detectable diesel temperature.
Despite continued resistance, the 130° values remain constant in the VAGCOM, and a sender short circuit is detected around approximately 70 Ohms.

The fatal thing about this tuning is, of course, that the effect is at its highest when the engine is cold, even though you should not drive "sportily" exactly in that situation.

However, this risk could be countered, for example, by incorporating a self-triggering FET that only "switches on" when the input voltage decreases, which corresponds to the "warming up" of the motor, thereby making the input characteristic curve "more aggressive".

I'm attaching a drawing to show you my general idea.

Before I try it myself (of course, not in public transport ), I would like to know first whether a diesel temperature tuning on a warmed-up engine is actually worthwhile from a performance perspective.

Has anyone already had secure experiences with this method?
The ideal scenario would be (of course) a statement regarding the DZR time in normal conditions and with temperature tuning, under otherwise identical conditions, including the resistance value and the simulated diesel temperature increase.

And of course, the question for the professional electronics technicians: can the circuit with the FET function as I have designed it, or have I made a mistake in my calculations?

Hello Ulf
I had a 2001 Golf 4 with a 74kW engine and ATD transmission.
also sometimes also a 'tuning' installed
was a nicely packaged 150-Ohm resistor from eBay for 17,-€

had also mentioned this in an older thread,
but I was standing quite alone with my opinion, that it would be worthwhile.

But I didn't perform a 'drag race,' but only compared a 'test course.'
Result: 80-120 in the 5th. Gang, approximately 250m instead of approximately 350m with resistance.
The car was really fast, even in warm weather! Much better.
After approximately 10,000 km, the clutch started to slip.
I decided to keep it, because I need the car for work.

When the machine is cold, you have to be extra careful not to step on it.

yes and to your switch
I wouldn't want to go to that much trouble.
(not to mention expressing an opinion about it, my teachings are too outdated)

but you remain dependent on the diesel temperature
and actually, you want to regulate something depending on the block temperature!

I would rather try to add an additional NTC to the block.
to screw in, check the specifications, use a suitable resistor in series.
and leave the diesel temp-NTC open.
Then is:
Engine cold - NTC high-resistance - Injection quantity correction to minimum
Motor warm - NTC low-resistance (short circuit??) - Resistance determines injection quantity correction.

or not?

Hi,

So, I can only say that the FETs exhibit VERY high variations, both in terms of the turn-on voltage and their temperature dependence.

Best regards, Roland

I find the idea and the purpose very good, however, the effort is really quite 'intense'. For someone who loves their car, takes care of it, and maintains it, this is exactly what they need. However, for everyone else, it's either irrelevant or they simply drive a bit until the engine warms up, which is how I do it

Greetings

durnesss wrote:

but you remain dependent on the diesel temperature and actually, you want to regulate something depending on the block temperature! I would rather try to add an additional NTC to the block. to screw in . . .

Sometimes - I actually don't want to deviate from the rule regarding diesel temperature.

Because if one only regulated the block temperature, after a long, slow run, giving full throttle would result in a significantly lower diesel temperature than the block temperature -> this creates the illusion of much more power.
But within a short time (roughly 1 minute), the diesel temperature approaches the engine block, and the performance decreases towards normal levels.

"A similar effect also arises from my parallel connection of the diesel generator and the tuning resistor: as the diesel temperature increases, the NTC value increasingly determines the total resistance of the generator, and therefore the reported temperature - but the latter still increases noticeably with the actual diesel temperature, meaning that the correction function remains essentially in effect."

And the "gradually" decreasing auxiliary function with increasing diesel temperature would, in my opinion, actually be a welcome protection against permanent extreme stress on the engine and drivetrain -> it would ultimately depend on the design of the entire system.

I would remove a suitable potentiometer with a switch from an old radio and connect it with a corresponding standard resistor (to ensure it doesn't fall below 100 ohms or so) and then install the whole thing as a damper wheel (in parallel with the standard NTC)

See you, Gremlin

Gremlin wrote:

I would remove a suitable potentiometer with a switch from an old radio and connect it with an appropriate series resistor (to ensure that it does not fall below 100 ohms or so), and then install the whole thing as a thermistor (in parallel with the series NTC thermistor).

Hi Ralf,

Also, hier ist auch eine Idee - und für die Skalenbeschriftung werden die DZR-Zeiten verwendet

Hello,

I just had another idea:

At least visually, the NTC sensor fittings for diesel and water in my engine are so similar that they might be interchangeable.
I had already removed the diesel pump - this can still be done with reasonable effort + mess.
But at the water pump located at the rear of the engine, the cooling system would run dry.

According to my measurements, the resistance values shift approximately 20°C out of phase - with the water supply having the lower resistance values.

Perhaps, one could simply replace the diesel injector with a water injector (if they are the same size) and thus have a very inconspicuous modification, without losing the ability to adjust the amount via diesel temperature.
(However, one would hardly get a watering can for 30 cents )

The donors, which I mean, have a 2-pole connection, "front" a stepped metal cap and sit in a rubber O-ring, which protects them from water/ Diesel pipe system sealed.
They are secured against sliding using a U-shaped metal clip on the cable side.

If someone has access to such devices, they might want to check if they actually have the same dimensions - at least the electrical connection or the cable-side connectors look completely identical.

Approximate resistance values at 0 / 10 / 20°C:
Diesel: 15 kOhm / 10 kOhm / 6 kOhm
Water: 6 kOhm / 3.9 kOhm / 2.6 kOhm

@ulf:

What I would be interested in knowing is whether the MSG activates this mysterious fuel cooling (0%<->100%) at diesel temperatures. Could you please check this for me as soon as possible? Thank you...

Does it not work for me either, even though the diesel temperature is 128 degrees?

m3nx wrote:

It doesn't work for me even though the diesel temperature is 128 degrees, it doesn't work at all.

Hi,

Will this temperature actually be reached, or is there a "fault" in the system?

If so, what is the impact: e.g., in terms of performance and the difference between the energy consumption display and the amount of water consumed overnight?

Hi!

An error is only logged at exactly 131 degrees in the control unit, therefore I also chose a resistor that corresponded to 128 degrees, so it fits perfectly, and I'm not getting worked up about the 2 degrees.

So far, I haven't been able to identify any differences between the night fuel consumption and the display. The consumption increased by approximately 1 liter when 'constantly pressing' the pedal, and decreased by about half a liter in partial load situations due to the higher torque and the resulting shorter fuel injections.

So far, I'm really completely satisfied with my 5c method.

I am still looking for a way to also make the new LMM with a 4 (or 5?) pole flat connector 'fake' a maximum air volume with a diode. Does anyone happen to know the pinout? I still have enough diodes in my junk drawer, I just need to figure out where to connect them.

Greetings

I had to do the diode test on the go, as the LMM on the train wasn't working anymore. With the PD (at least with my STG), this isn't possible. The little motor is making the strangest noises. The STG is trying to open and close the AGR wildly, and doing something else. Not to mention the errors that are being logged. With a diode, the car wasn't drivable, it made those noises. In the low-speed range, the engine is usually almost dead, because the MSG was trying everything possible to reduce the air intake.

Hi!

Mmh... then the new LMM or control unit is probably 'smarter'.

The problem will be that a 'short circuit' between the measuring pin and the power supply will prevent the control unit from recognizing the maximum permissible air volume of, for example, 850 mg/h, but instead, it will detect much too much, so it will try to reduce it. In older VP-TDI engines, the measuring range eventually stopped working. It simply displayed 'enough' air was available, and not too much.

So, I will probably have to try to determine the 'ideal amount' using resistors. It should probably be somewhere around 850 mg/h.

Do you know which pins I need to use?

Greetings

@m3nx

Even the resistors won't help you. After the Heimringer with a diode, my ambition took over, and I started testing further. Even three diodes resulted in the same problem in the lower speed range, where there was logically insufficient power because the reported air volume was too low. Therefore, I think it will be the same with resistors. You would need a variable resistor depending on speed and possibly load pressure. Otherwise, according to my opinion, this won't work with the STG's of this generation! The cause of this behavior is most likely the compliance with emission regulations.