Left foot braking with foot on throttle- how does car interpret simultaneous pedal inputs?

[WuffvonTrips]

In track driving at full throttle, when taking a nearly flat-out corner (so not a common scenario), when it might be better to transfer weight by braking while staying on full throttle, how does the Taycan react to those inputs- does it give one pedal priority and ignore the other, or try and apply the intended net effect of both inputs, or maybe do something clever like keep the motors at full "throttle" while only braking with the physical brakes? Or regen brake with the front motor while powering the rear one?

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[Hirschaj]

In track driving at full throttle, when taking a nearly flat-out corner (so not a common scenario), when it might be better to transfer weight by braking while staying on full throttle, how does the Taycan react to those inputs- does it give one pedal priority and ignore the other, or try and apply the intended net effect of both inputs, or maybe do something clever like keep the motors at full "throttle" while only braking with the physical brakes? Or regen brake with the front motor while powering the rear one?

I think @bsclywilly has some good experience with this.

 

[WuffvonTrips]

I think @bsclywilly has some good experience with this.

Thanks- I thought he would be a likely one, hopefully will appear now he has been named.
My rudimentary search hadn't turned up a relevant thread.

 

[bsclywilly]

In track driving at full throttle, when taking a nearly flat-out corner (so not a common scenario), when it might be better to transfer weight by braking while staying on full throttle, how does the Taycan react to those inputs- does it give one pedal priority and ignore the other, or try and apply the intended net effect of both inputs, or maybe do something clever like keep the motors at full "throttle" while only braking with the physical brakes? Or regen brake with the front motor while powering the rear one?

At partial throttle, brake application will cut power so it’s kind of the net effect while also applying the mechanical brakes. I would assume it’s the same at full throttle. You can see the power meter go down in the central tube while also feeling the deceleration of the brakes. It works well on the track since it’s very smooth and doesn’t cut power abruptly. I did notice I have more tendency to adjust speed with the left foot than when driving with one foot though which means I’m riding both pedals more often.

The other piece to the puzzle for high performance driving is how the brake balance and front/rear power split is executed. Is there any interesting torque split going on or do the brakes just do their thing and power is cut in the same proportion for both motors? This could have benefits for cornering balance when your tires are already at the limit of lateral grip and maybe take into consideration steering inputs if it’s advanced enough. Something to try on a skid pad…

I’m also kind of curious if you really stepped on the brakes while on throttle at what point, if there is one, that power to the motors gets cut completely. With ever increasing EV power, we’re at a point where motor power is actually greater than the power generated by brakes. Just hope these high power EVs don’t have a case of unintended acceleration, otherwise you’re along for the ride!

 

[WuffvonTrips]

At partial throttle, brake application will cut power so it’s kind of the net effect while also applying the mechanical brakes. I would assume it’s the same at full throttle. You can see the power meter go down in the central tube while also feeling the deceleration of the brakes. It works well on the track since it’s very smooth and doesn’t cut power abruptly. I did notice I have more tendency to adjust speed with the left foot than when driving with one foot though which means I’m riding both pedals more often.

The other piece to the puzzle for high performance driving is how the brake balance and front/rear power split is executed. Is there any interesting torque split going on or do the brakes just do their thing and power is cut in the same proportion for both motors? This could have benefits for cornering balance when your tires are already at the limit of lateral grip and maybe take into consideration steering inputs if it’s advanced enough. Something to try on a skid pad…

I’m also kind of curious if you really stepped on the brakes while on throttle at what point, if there is one, that power to the motors gets cut completely. With ever increasing EV power, we’re at a point where motor power is actually greater than the power generated by brakes. Just hope these high power EVs don’t have a case of unintended acceleration, otherwise you’re along for the ride!

Thanks for sharing your experience. So the way the Taycan responds sounds worth my while to try and develop a feel for it. I don't have enough consistency between laps- or corners for that matter- to introduce another complication at this stage, but it in the meantime it could be something useful for me to do after thermal management curtails full power, rather than end a run. Oh and I need to get the power meter back up on my display to experiment when it's safe on public roads (I'm not sure my inexperienced mind has sufficient bandwidth to be checking the dials whilst concentrating on staying on line on track).
On your other good points regarding how the car might respond to inputs, I wonder if there's any way to log and review the inner workings? (I'm assuming that the Porsche track precision app or whatever it's called only shows control inputs rather than responses- I need to find the thread on that subject.)

 

[bsclywilly]

Track precision can show your throttle and brake inputs. It's a really good set of data for analysing your driving inputs. CarScanner (or any other OBD apps with logging) can show more traces, like power output, and throttle, but I don't see a brake pressure sensor in the standard list of sensors. Nor are there individual motor power readings. They likely exist but need the OBD PIDs decoded.

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