Mercedes Power Unit Hardware & Software

[Big Tea]

Thanks everyone for your contribution, but my reckoning is TAG mode is directly linked to performance.

Just 2 examples to illustrate my opinion.

In Australia, lap 21. KR had pitted, Merc responded by pitting Lewis to cover the undercut. He gout out in front of Kimi, and they (mistakenly) thought they had Vettel covered in case of VSC, and then came the message :

Bono : "OK Lewis, you can drop your tag level if we can maintain Vettel’s time. He’s doing a 28.2."

Another example, during the US GP :

PB : "And we can drop to Tag mode 2, tag mode 2."

So I think it's directly linked to performance, but contrary to "Strat" mode, I don't know what this TAG mode is about.

Would you reckon Strat mode 3 is more agressive or less agressive than Strat mode 5 ?

Is he saying 'tag'? I assumed it was Tac, as tactical?

(edit) as in one knob for strat=strategic. Race long etc. One for Tac=Tactical or instantaneous settings.

[Marble]

Thanks everyone for your contribution, but my reckoning is TAG mode is directly linked to performance.

Just 2 examples to illustrate my opinion.

In Australia, lap 21. KR had pitted, Merc responded by pitting Lewis to cover the undercut. He gout out in front of Kimi, and they (mistakenly) thought they had Vettel covered in case of VSC, and then came the message :

Bono : "OK Lewis, you can drop your tag level if we can maintain Vettel’s time. He’s doing a 28.2."

Another example, during the US GP :

PB : "And we can drop to Tag mode 2, tag mode 2."

So I think it's directly linked to performance, but contrary to "Strat" mode, I don't know what this TAG mode is about.

Would you reckon Strat mode 3 is more agressive or less agressive than Strat mode 5 ?

Is he saying 'tag'? I assumed it was Tac, as tactical?

(edit) as in one knob for strat=strategic. Race long etc. One for Tac=Tactical or instantaneous settings.

It might be TAC, affirm (I'm not sure about the final letter).
But there's nothing like TAG or TAC *written* on the steering wheel, this is why I'm struggling with it.

[Dr. Acula]

Thanks everyone for your contribution, but my reckoning is TAG mode is directly linked to performance.

Just 2 examples to illustrate my opinion.

In Australia, lap 21. KR had pitted, Merc responded by pitting Lewis to cover the undercut. He gout out in front of Kimi, and they (mistakenly) thought they had Vettel covered in case of VSC, and then came the message :

Bono : "OK Lewis, you can drop your tag level if we can maintain Vettel’s time. He’s doing a 28.2."

Another example, during the US GP :

PB : "And we can drop to Tag mode 2, tag mode 2."

So I think it's directly linked to performance, but contrary to "Strat" mode, I don't know what this TAG mode is about.

Would you reckon Strat mode 3 is more agressive or less agressive than Strat mode 5 ?

Is he saying 'tag'? I assumed it was Tac, as tactical?

(edit) as in one knob for strat=strategic. Race long etc. One for Tac=Tactical or instantaneous settings.

It might be TAC, affirm (I'm not sure about the final letter).
But there's nothing like TAG or TAC *written* on the steering wheel, this is why I'm struggling with it.

Well, i looked it up and i didn't find what TAG actually stands for, but i found one intresting thing about it here. https://www.racefans.net/2017/09/25/201 ... ranscript/
It's a transscript from the 2017 Singapore team radio chatter and in lap 38 the pit asked Lewis in which TAG mode he is in. So apparently they can't see that in the telemetry which let me doubt that it has anything to do with the engine.

[subcritical71]

Well, i looked it up and i didn't find what TAG actually stands for, but i found one intresting thing about it here. https://www.racefans.net/2017/09/25/201 ... ranscript/
It's a transscript from the 2017 Singapore team radio chatter and in lap 38 the pit asked Lewis in which TAG mode he is in. So apparently they can't see that in the telemetry which let me doubt that it has anything to do with the engine.

Just a WAG.. the ECU's run in F1 are all McLaren Electronics TAG-320's. Could the reference to TAG-x reference a mode of the ECU itself? What I am thinking is that there are alot of protective features that the ECU can have and maybe for different race scenarios the teams may wish to use different 'risk' settings in the ECU. So for instance, in TAG-1 all protections are enabled. In TAG-2, as an example, all turbo related protections are either defeated or have a multiplier applied so the protection would take longer to become triggered.

So while the STRAT modes cover PU strategies (harvest/deployment, ICE tune, etc), the TAG modes could control some other portion of the ECU (in my guess, the protective functions associated with the PU).

[Sierra117]

Here's a fun game of speculation. What are the ways in which we think Lewis' engine was failing? Physically speaking. Deformities in the pistons and block? Residue build up?

And how about the ways the engineers adjusted values to keep it alive just long enough?

[hurril]

Here's a fun game of speculation. What are the ways in which we think Lewis' engine was failing in? Physically speaking. Deformities in the pistons and block? Residue build up?

And how about the ways the engineers adjusted values to keep it alive just long enough?

How about this speculation?

There was no real problem with it, they were trying out parameter boundaries and want to do that some more now that the championship is already settled.

[djones]

They could just test that on a dyno.

[63l8qrrfy6]

I heard from 2 different sources that their VLIM failed on one bank.

[Jolle]

I heard from 2 different sources that their VLIM failed on one bank.

Guess the rule is that you are not allowed to break a seal. Wonder how much they can repair trough key hole surgery true the air intake tubes

[63l8qrrfy6]

The intake is outside the FIA seal, it can be replaced without a penalty.
I think they are concerned about some secondary damage.

[henry]

If the VLIM failed, stuck in one position, I assume that would mean that for most of the Rev range the air-fuel ratio would be too rich. Would that lead to high exhaust temperatures as were reported to be an issue that needed to be managed?

[63l8qrrfy6]

If the VLIM failed, stuck in one position, I assume that would mean that for most of the Rev range the air-fuel ratio would be too rich. Would that lead to high exhaust temperatures as were reported to be an issue that needed to be managed?

Yes, that's what I thought too.
Temps should climb as the mixture gets 'less lean' and approaches stoich then drop again as it gets past and becomes rich.

I believe this has to do with the additional thermal mass of the excess air (in the case of lean mixtures) and that of fuel (in rich mixtures) that does not react. Since the specific heat of air is smaller than that of fuel the temperature should drop at a faster rate when going from stoich to rich compared to when going from stoich to lean.

So I guess the reduction in airflow made it run closer to or bang on stoich?

[Dr. Acula]

If the VLIM failed, stuck in one position, I assume that would mean that for most of the Rev range the air-fuel ratio would be too rich. Would that lead to high exhaust temperatures as were reported to be an issue that needed to be managed?

Not necessarily. Normally the system is able to adapt to a certain degree. You can't run an absolute A/F mapping anyway because you have to atleast take some meteorological changes into account during the race.

[gruntguru]

If the VLIM failed, stuck in one position, I assume that would mean that for most of the Rev range the air-fuel ratio would be too rich. Would that lead to high exhaust temperatures as were reported to be an issue that needed to be managed?

Too rich on that bank would be a reasonable assumption although it is highly likely they can control fuel quantity per bank and probably per individual cylinder. This would allow them to lean out the rich cylinders slightly and fatten up the other three to stay at the 100 kg/hr limit.

[zokipirlo]

If the VLIM failed, stuck in one position, I assume that would mean that for most of the Rev range the air-fuel ratio would be too rich. Would that lead to high exhaust temperatures as were reported to be an issue that needed to be managed?

Not just that, too much fuel in mixture would also mean big fuel consumption. They would be cruising last laps, don't believe that they have so many extra fuel for "just in case". And it was a dry track without SC so no time to save fuel.