Target Lambda values - WOT Fueling Question - 2013 Audi S6

I've been scouring the tables for the last three days trying to figure out exactly how this tune requests a Lambda value at a targeted load value, and it's not entirely clear to me yet.

As I understand it looking at the tables so far, it appears that the engine operates as a closed loop system full time, and open loop is a transient state utilized for startup and a few other transient situations.

One table I have yet to identify is how to define target Lambda values for a given load.

I have found a minimum and maximum lambda value, and an acceleration enrichment vs ECT multiplier table under the Engine ---> Fuel ---> Transient Tab.

However a clearly defined lambda vs load table eludes me or an actual Acceleration enrichment.

Anyone have any ideas?

It appears there are more tables and limiters required to be utilized to properly calibrate this vehicle.

I’ve been able to command increased load values by ‘tricking the PCM’, however, I would like my final product to be free of “incorrect” values or “hacks”.

Is there someone who can reach out to me to discuss this further?

Let’s get this software dialed.

Let’s get this ball rolling... still waiting for required parameters.

From what I can see on quick glance, the module in charge of Power Enrichment does not exist with your operating system.
As such Lambda is targetted to 1.0 and changes only once overtemp kicks in. I've seen this a few times, but I'll do a deeper look just to double check.

Even if you did have the Power Enrichment module, on these vehicles it is not Lambda vs Load. Its an enrichment that activates based either on a pedal position or engine torque request exceeding a set value.
The days of RPM vs Load vs Lambda have long since passed for many vehicles.


As for the torque limitations, do you mean you know of additional tables restricting this? From what I can see, you have Driver Demand, Monitoring, Extended monitoring, maximum indicated torque limits (including the overboost), I would think you have everything necessary to not require cheating the system.
That said, one thing that may popup is the transmission clipping your maximum torque regardless, for which there is no easy bypass short of cheating or tuning the transmission.

If you have knowledge of whats missing, please contact us at [email protected] and let us know so that we can work on getting those added for you.

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Originally Posted by Steven@HPTuners

From what I can see on quick glance, the module in charge of Power Enrichment does not exist with your operating system.
As such Lambda is targetted to 1.0 and changes only once overtemp kicks in. I've seen this a few times, but I'll do a deeper look just to double check.

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Ahhh... I see.

Well as it stands right now.

As soon as I go WOT, the PCM commands a Lambda value of .90. Which tells me the PCM is getting a commanded Lambda value of .90 from somewhere.

I have yet to identify where that target value is coming from in the maps provided by HPTuners

After a moment, as EGT?s rise, it does indeed enter overtemp mode and I?m able to get the commanded Lambda values from the overtemp tables.

Prior to the overtemp tables kicking in I can feel the car dip in power. Knock climbs, the car get sluggish, the overtemp table kicks in, the car smooths out, and begins ramping timing back in.

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Even if you did have the Power Enrichment module, on these vehicles it is not Lambda vs Load. Its an enrichment that activates based either on a pedal position or engine torque request exceeding a set value.
The days of RPM vs Load vs Lambda have long since passed for many vehicles.

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This is EXACTLY what I am looking for. There?s no doubt in my mind I could invest the time to get this programmed to smooth the transition between the commanded value of .90 and the overtemp tables by manipulating a few values and making the transition to overtemp occur sooner. However, based on what I?m seeing the vehicle do, this doesn?t seem like the ?correct? approach. I am a huge advocate of utilizing tables for what they were designed to be used as, and utilizing the safeguards of the PCM for their intended purpose.

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As for the torque limitations, do you mean you know of additional tables restricting this? From what I can see, you have Driver Demand, Monitoring, Extended monitoring, maximum indicated torque limits (including the overboost), I would think you have everything necessary to not require cheating the system.

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Through testing the limits of different values I have run into a hang up in the maximum throttle plate angle I have been able to command which leaves a significant portion of the table unusable. I have been able to plug the desired load at ?WOT? and achieve my targeted results. I suppose I could rescale the table and take advantage of the full resolution of the table, however, this also seems to me to be the incorrect way to achieve my targeted load values.

I try to only post things here when I reach the end of my ability to scour tables, manipulate values, and achieve desired results as I interpret what I believe is what the great engineers at Bosch intended for the this PCM is supposed to fuel the engine.

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That said, one thing that may popup is the transmission clipping your maximum torque regardless, for which there is no easy bypass short of cheating or tuning the transmission.

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Where there is a will there is a way... it wouldn?t be the first time I?ve rescaled an entire PCM in order to achieve a desired result... :p

Again... I just prefer to do it the ?right way?.

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If you have knowledge of whats missing, please contact us at [email protected] and let us know so that we can work on getting those added for you.

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I am far from an engineer, or a programmer, but I have been highly successful in calibrating high horsepower engines ?that work good and last long time? on a wide range of platforms, and engine management systems.

I only have about 100 hours or so into studying and testing the results of manipulating values of this PCM. 9,900 to go before I?ll be able to call myself an expert. Haha.

But... I?m young, retired, and aside from making sure my small children survive to adulthood. I have the time on my hands to really learn the fundamentals of operation for this PCM.

This is also my first venture into direct injected engines (gasoline anyway), and as such have a bit more theory of operation to brush up on as well.

So much to learn...

One more thing...

Sincerely thank you for your response.

It was well thought out, and insightful.

Alright. I got this all sorted.

One of the most valuable pieces of information I received out of this post was the hint about the transmission control module clipping your maximum torque values.

Figure out how to work around that, and you’re in business.

It’s tricky, but if you get creative it is possible.

With that said, getting the transmission tables sorted for the DCT would be a far more accurate way to tune this vehicle so that the gearbox also understands it is now receiving more power.

It would be pretty awesome to be able to write a custom program for the DCT with HPTuners.

Kaploww - I'd be interested to see where you ended up with the 2013 S6 as I have one as well. Do you have any additional information you'd be willing to share?

I recently got rid of my a7 and bought a 2014 S6. So ill be venturing into tuning the 4.0t very soon. Collecting parts at the moment.

Attachment 106894

Would be interested to see others for comparison.