Part 3: The Quest for the Perfect Tune

[prj]

Was this an AWD Dyno? How much is the real HP to the "Crank" when you factor in drive trian loss?

AWD of course, how else.

The dyno showed 900 at the wheels.
The motors produce 940 PS, I have this info from datalogging the motors themselves, so that is the 100% accurate number.

We had a J1.1 4S on the dyno as well in Greece:

That shows 770PS at the crank, but I know from the motors it makes 730 PS.
Ignore the torque figure, impossible to get that right on the dyno because the front and rear RPM is different and the dyno gets the torque by dividing the power by the rpm (well a bit more complicated than that before someone corrects me).

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[Emm]

J1.2 Taycan 4S put down 900 WHP at 70% SoC on a dynojet with our tune.

Quick question: Is the figure 800 PS for the J1.1 GTS the actual output from the combined engines, or is it the output measured at the wheels (like the J1.2 4S above; hopefully this :–)? If the latter, what is the actual engines output; if the former, what is the estimated output at the wheels?

 

[prj]

Quick question: Is the figure 800 PS for the J1.1 GTS the actual output from the combined engines, or is it the output measured at the wheels (like the J1.2 4S above; hopefully this :–)? If the latter, what is the actual engines output; if the former, what is the estimated output at the wheels?

It's the actual output. The motors know exactly how much power and torque they are producing at any given point, and I got the real world curves for the motors by testing the cars at full acceleration on the street.

 

[Emm]

Thanks. Just out of curiosity, what would you expect the output at the wheels to be then (on the J1.1. GTS), i.e. what is a likely estimate of drive train loss for these AWD cars?

 

[prj]

Thanks. Just out of curiosity, what would you expect the output at the wheels to be then (on the J1.1. GTS), i.e. what is a likely estimate of drive train loss for these AWD cars?

I have no idea. If you trust dynojet the loss is 5%, but it's probably more than that.

 

[Emm]

Ok, that's still pretty low compared to AWD ICE transmission losses :–). You wrote above that the output from the engines on the J1.2 4S is 940 PS, and as it was measured to be 900 PS at the wheels on the dyno, the transmission loss is only ~4.3%. Do you know of any technical reasons for it to be slightly more on the J1.1 GTS, or would it likely be in the same range (4-5%)?

 

[prj]

Ok, that's still pretty low compared to AWD ICE transmission losses :–). You wrote above that the output from the engines on the J1.2 4S is 940 PS, and as it was measured to be 900 PS at the wheels on the dyno, the transmission loss is only ~4.3%. Do you know of any technical reasons for it to be slightly more on the J1.1 GTS, or would it likely be in the same range (4-5%)?

I would take the dyno measurement with a grain of salt. Dynojet likes to read high as well. Would not make any conclusions from that about the losses.

The only thing I can be sure about is what the motors put out, because an electric motor controller knows exactly without a single bit of doubt how much torque the motor is putting out at any given operating point.

The dyno measurement is flawed, it is mostly useful to compare before and after results. It would have been good to measure that Taycan with a stock ASG and then with the tuned one, and note the difference.

The dyno plots are just there to confirm that I am not full of shit and making numbers up, like is common in the industry

 

[Loe]

Ok, that's still pretty low compared to AWD ICE transmission losses :–). You wrote above that the output from the engines on the J1.2 4S is 940 PS, and as it was measured to be 900 PS at the wheels on the dyno, the transmission loss is only ~4.3%. Do you know of any technical reasons for it to be slightly more on the J1.1 GTS, or would it likely be in the same range (4-5%)?

When you near the limits of the battery, it becomes less efficient; in general more heat is loss above 90% of it's discharge rate, below that rate, it's relatively stable as long as it has a good battery cooling system. The J1.1's 300a/600a combo are close to maxing out their batteries vs the J1.2, which would contribute to some minor loss.

 

[prj]

When you near the limits of the battery, it becomes less efficient; in general more heat is loss above 90% of it's discharge rate, below that rate, it's relatively stable as long as it has a good battery cooling system. The J1.1's 300a/600a combo are close to maxing out their batteries vs the J1.2, which would contribute to some minor loss.

I don't think you quite understood what he was talking about. He was talking about the physical powertrain loss between the motor output shaft and it getting to the wheels.
The battery is irrelevant in this case.

It's mostly the friction of the front reduction gearset and the rear gearbox.

 

[Loe]

I don't think you quite understood what he was talking about. He was talking about the physical powertrain loss between the motor output shaft and it getting to the wheels.
The battery is irrelevant in this case.

It's mostly the friction of the front reduction gearset and the rear gearbox.

Ah! makes sense. Yeah I completely missunderstood in this case.

 

[Emm]

Ok, so now I've had the MAP EV tune in my 2023 GTS Sport Turismo (800 PS / 910 NM) for a short while. I haven't been able to track the car as fall has arrived and there are no more scheduled track events, but in the spring I will take it to the track and really push it. Nor have I been able to clock the 0-100 km/h acceleration yet, as I have a Dragy V2 on order but still haven't received it. Theoretically I think the car should now do around 2.8-2.9 secs(?), but it feels like that might be tough to achieve as there are constant traction issues when giving full throttle (with ASC On, in Sport mode, and Off as well). The car came with the Goodyear Eagle F1 Asymmetric 3 UHP tyres, and I figure I'll let them wear out before replacing them with Michelin PS 5S (or is it "S5" now?), which I have on my tuned RS6 (and my son has on his tuned M140ix) and am very pleased with (I've had 4S on all my latest cars before).

What I can say based on street driving only, is that the improvement in acceleration can be felt clearly, and it's easy for me to compare with original as my tune is configured so that I only have the power increase (800 PS) in Sport and Sport Plus mode—in Normal mode the power remains at 520 PS (600 PS with launch control).

Still, there must be something wrong with me because 800 PS is not enough—I want even harder acceleration! The Turbo GT is currently out of reach, but my ambition is to to upgrade to a J1.2 GTS (or perhaps J1.3 when that comes out) in a couple of years; overall I'm super pleased with the Taycan GTS, it's the best car I've ever had (before my previous tuned Cayman GTS 4.0 and my current tuned RS6 Avant), but I just can't seem to get enough acceleration...

For anyone considering getting the MAP EV tune, I would absolutely recommend it, and if anyone has specific questions about the tune on a GTS J1.1 (driver experience related; the technical questions should of course be directed to jpr), feel free to ask.

 

[lcarron]

Thanks for the update. Is the tune availability on Sport & S plus an extra feature from MapEV?
I thought the increased power was available in every drive mode.

 

[prj]

Thanks for the update. Is the tune availability on Sport & S plus an extra feature from MapEV?
I thought the increased power was available in every drive mode.

You can request this if you like. Same as you can request more regen.
We don't charge anything extra for it.

I always recommend not to do this, because there's already a very pronounced difference between normal and sport (gearbox in 2nd or 1st gear), but ultimately that's the customers decision.

 

[Mad Matter]

I always recommend not to do this, because there's already a very pronounced difference between normal and sport (gearbox in 2nd or 1st gear), but ultimately that's the customers decision.

Is the reason you don't recommend having 'Normal mode' stay detuned due to switching from Normal to Sport while under throttle and the power difference is a big shock to the powertrain or something more along the lines of driving dynamics and possibly destabilizing the car?

 

[prj]

Is the reason you don't recommend having 'Normal mode' stay detuned due to switching from Normal to Sport while under throttle and the power difference is a big shock to the powertrain or something more along the lines of driving dynamics and possibly destabilizing the car?

No, this is blended.

The reason I don't recommend it is because it's pointless. The tune doesn't make the pedal more sensitive, it's just in the upper half of the pedal movement stuff happens instead of not happening - stock the upper 1/3 of the pedal does pretty much nothing below 100kph.
Most people asking for the function think that the car is going to lurch or jump forward by itself just because it has more power which is absolutely not the case. Feels exactly the same until you're in the upper 2/3 of pedal travel.

It's pointless because you're in 2nd gear in Normal at lower speeds. Until you really floor the car and make it kick down into first gear you're not going to have much power increase. And if you have your foot all the way to the floor then you want all the power at that point anyway.

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