Anyone upgraded brakes/brake feel? Too soft!

[or1]

Perhaps a silly question... but doesn't the Taycan have "brake by wire", meaning that there's no mechanical connection between the brakes and the brake pedal? isn't it in fact a physical connection between the brake and the brake servo taht simulates pedal push back, and itself balance electric motor regeneration with physical brakes. So when you are pushing on the pedal, what you're feeling is not the pressure form the brake pads on the rotors?

Hence isn't a brake bleed meaningless? and instead a calibration of the brake servo is required?

Yes it is brake by wire. But there can still be a "transfer" of pressure in the hydraulic system to the pedal feel, managed by software.

I agree that the pedal feels unnaturally soft at really low speeds. See the other thread mentioned above for how Porsche explains this as intentional. I'm not sure they have hit the nail on the head, but there is an explanation at least.

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[f1eng]

Perhaps a silly question... but doesn't the Taycan have "brake by wire", meaning that there's no mechanical connection between the brakes and the brake pedal? isn't it in fact a physical connection between the brake and the brake servo taht simulates pedal push back, and itself balance electric motor regeneration with physical brakes. So when you are pushing on the pedal, what you're feeling is not the pressure form the brake pads on the rotors?

Hence isn't a brake bleed meaningless? and instead a calibration of the brake servo is required?

It is complex but below about 7 ½ mph only the friction brakes are used and it is in this use case, in crawling traffic and manouvering, that the pedal is soft on some cars, indicating a need for bleeding.

If they need bleeding a similar soft feel would take place before regenerative braking is initiated each day when first setting off whilst the car cleans the discs.

Also the plated and composite brakes have inferior bite to cast iron when wet, which will complicate the issue if you have them.

AFAIK the brake pedal is directly controlling the hydraulic side of the braking.

 

[or1]

It is complex but below about 7 ½ mph only the friction brakes are used and it is in this use case, in crawling traffic and manouvering, that the pedal is soft on some cars, indicating a need for bleeding.

If they need bleeding a similar soft feel would take place before regenerative braking is initiated each day when first setting off whilst the car cleans the discs.

Also the plated and composite brakes have inferior bite to cast iron when wet, which will complicate the issue if you have them.

AFAIK the brake pedal is directly controlling the hydraulic side of the braking.

Very interesting. My knowledge around this is just scratching the surface compared to yours. But how do they do the more forceful retardations (ACC when catching up on a slow car, InnoDrive before turns etc, emergencies) if there isn't brake-by-wire? Do they add by-wire braking power by increasing pedal pressure by other means than the driver's foot then? I may come across as a simpleton here, so I'd very much like to learn.

 

[FlyingPoint]

FWIW, I agree with the OP. The Taycan brakes feel very different from a 991 or a 992. Its not that the brakes fail to stop the car, they just feel different. Note: I am not referring to low speed excessive travel that is the subject of much discussion and a service bulletin https://www.taycanforum.com/forum/t...-a-standstill-july-18-2023.16886/#post-259607
I just came out of 2 yr. service with a brake flush performed and there is no noticeable difference.

I am fairly certain this is the result of design and regen software.

 

[f1eng]

Very interesting. My knowledge around this is just scratching the surface compared to yours. But how do they do the more forceful retardations (ACC when catching up on a slow car, InnoDrive before turns etc, emergencies) if there isn't brake-by-wire? Do they add by-wire braking power by increasing pedal pressure by other means than the driver's foot then? I may come across as a simpleton here, so I'd very much like to learn.

Since the regeneritive braking is all “by wire”, so up to the point where an emergency stop is required all the retardation can easily by wire.

The emergency braking will be hydraulic over-ride as well, I don’t know how
exactly the Porsche emergency stop actuates the hydraulics.

 

[dtich]

a couple somewhat redundant articles on braking in Taycan, some of that info may be new to you; a tech paper that illustrates classic and new brake-by-wire integration schemes; and then the obligatory bill nye preschool version...

https://newsroom.porsche.com/en/2023/innovation/porsche-engineering-brake-force-distribution-recuperation-30953.html#:~:text=The Porsche Taycan gets by,but the other way around.

https://cleantechnica.com/2023/01/27/porsches-approach-to-regenerative-braking/#:~:text=The Porsche Taycan is designed,used to boost battery power.

https://iopscience.iop.org/article/10.1088/1742-6596/2479/1/012051/pdf#:~:text=Brake by wire system includes,mechanical brake system (EMB).

 

[DexD]

my '22 with PSCB was exactly the same, and very disconcerting when coming from nearly any other car- my wife refused to drive it. The dealer took it for a few days, and made a significant improvement, but that was May, so the PSM update will hopefully help it further

 

[noev]

FWIW, I agree with the OP. The Taycan brakes feel very different from a 991 or a 992. Its not that the brakes fail to stop the car, they just feel different. Note: I am not referring to low speed excessive travel that is the subject of much discussion and a service bulletin https://www.taycanforum.com/forum/t...-a-standstill-july-18-2023.16886/#post-259607
I just came out of 2 yr. service with a brake flush performed and there is no noticeable difference.

I am fairly certain this is the result of design and regen software.

Exactly.

FWIW, I agree with the OP. The Taycan brakes feel very different from a 991 or a 992. Its not that the brakes fail to stop the car, they just feel different. Note: I am not referring to low speed excessive travel that is the subject of much discussion and a service bulletin https://www.taycanforum.com/forum/t...-a-standstill-july-18-2023.16886/#post-259607
I just came out of 2 yr. service with a brake flush performed and there is no noticeable difference.

I am fairly certain this is the result of design and regen software.

Thank you for validating that I’m not totally crazy

I do think it is indeed a design flaw. If the power meter on the dash is to be believed, there’s no difference in regen when the car is coasting vs when the brake is pressed lightly (let’s call this the “travel phase”)…..assuming this is true (if certainly feels/looks to be) …then why have this dead area/play in the brake pedal at all? If I’m taking the action to hit the brake with some pressure, just eliminate the play and carry out whatever more aggressive regen/mechanical braking program is intended and happens after the “travel phase”. I really don’t see the point of the extra travel vs a 911, let’s say.

 

[Archimedes]

Not sure what you mean about extra travel. When I press the brake pedal in my car, I get immediate (recuperative) braking. There is no dead zone.

Also, comparing to a 911 - which brakes? The PCCB brakes have a different brake booster than the iron system and have more initial power. They feel very different from each other even.

 

[Avantgarde]

Exactly.


Thank you for validating that I’m not totally crazy

I do think it is indeed a design flaw. If the power meter on the dash is to be believed, there’s no difference in regen when the car is coasting vs when the brake is pressed lightly (let’s call this the “travel phase”)…..assuming this is true (if certainly feels/looks to be) …then why have this dead area/play in the brake pedal at all? If I’m taking the action to hit the brake with some pressure, just eliminate the play and carry out whatever more aggressive regen/mechanical braking program is intended and happens after the “travel phase”. I really don’t see the point of the extra travel vs a 911, let’s say.

I have the PSCBs and agree that it feels like there is some inconsistency in brake feel. (sometimes it is immediate sometimes there is a bit of a gap). The car choses to use steel breaks exclusively for a while at times (especially when you have not driven for a while), and you can tell this from the screen and the squeaking sound coming from PSCBs, during which I feel much better consistency. But once it starts blending regen with pads, things become spotty. All in all, I am pretty convinced Porsche did not do a top notch job calibrating the brakes in Taycan. Going over a pothole while braking for example occasionally creates confusion and a split second "gap" that you could actually feel on the pedal. I regularly switch back and forth between my wife's X5 45e and can totally feel the difference and how amazing of a job BMW did in blending of regen with pads compared to Taycan. BMW's brake feel absolute perfection. It is a pity for Taycan given the rest of the car is so precise...

 

[gusone]

Since the regeneritive braking is all “by wire”, so up to the point where an emergency stop is required all the retardation can easily by wire.

The emergency braking will be hydraulic over-ride as well, I don’t know how
exactly the Porsche emergency stop actuates the hydraulics.

Don't know how they do it but it works. Had to emergency brake yesterday when an UN marked police car flew round the corner on the wrong side coming towards me to avoid some silly sod who suddenly stopped on the other side of the road when they saw the rozzers in their rear view mirror. In what felt like slow motion the rozzers shicaned us. But he was so close it was like he was sitting in my lap. Brakes working.

 

[rkm]

Hi
This is my own "basic level" experience with a "soft" experience in my 2022 Taycan 4S - i certainly felt the brakes to be spongy/soft for the first couple months - a visit to the local dealer was met with "everything is good - no worries". I went back the second time and this was a "you must be imagining it" kinda of a response. I then sent the car back to the original dealer who bled the brakes - things appeared much better but that only lasted for a month or two - back to the original dealer who finally diagnosed to be a "leaky hydraulic unit" for the braking system - took three weeks to get the part from Porsche Germany and now things are a lot more normal.

 

[Jenner]

Hi
This is my own "basic level" experience with a "soft" experience in my 2022 Taycan 4S - i certainly felt the brakes to be spongy/soft for the first couple months - a visit to the local dealer was met with "everything is good - no worries". I went back the second time and this was a "you must be imagining it" kinda of a response. I then sent the car back to the original dealer who bled the brakes - things appeared much better but that only lasted for a month or two - back to the original dealer who finally diagnosed to be a "leaky hydraulic unit" for the braking system - took three weeks to get the part from Porsche Germany and now things are a lot more normal.

Your repair matches my '21 Turbo S that I brought to service in the beginning of August for the "Brake Pedal Travel Perceived as 'Too Long' Just Before the Vehicle Comes to a Standstill" issue:

https://www.taycanforum.com/forum/t...-a-standstill-july-18-2023.16886/#post-260607

EXCEPT

My Service Advisor test drove in their parking lot to replicate and almost hit a parked Porsche while attempting to park in a spot. He got that feeling in his stomach that the car wasn't stopping quick enough and he was going to hit the parked car in front of him exactly like I described in my notes, and he understood the issue first hand.

The service department also replaced my PSM control unit module since it wouldn't take the new code that came out with the TSB, but in the end it sounds like the hydraulic unit was the main issue which was also replaced on mine. Like you it took 3 weeks for the parts to arrive from Germany (they really need to stock these as it is a common Taycan issue!)

During the initial diagnosis I was miserable driving a brand new Panamera 4 and asked for my Taycan back while they waited for the parts. They would not let me have it even though no work had been started because they felt the car was too dangerous to drive in it's current state. Huge contrast from "everything is good" and "you must be imagining it!"

I believe the key items to help others get this diagnosed in the first visit are:

1) Print out the TSB and give it to the SA:
https://static.nhtsa.gov/odi/tsbs/2023/MC-10240398-0001.pdf

2) Explain to the SA or Porsche Tech that the car stops like a Porsche when using mechanical brakes(ie from high speed with deep pedal travel or when battery is at 100% the Taycan switches to 100% mechanical brakes since there is no place to put the recovered energy) but the brakes are scary in low speed high risk scenarios like stop and go traffic or when approaching an object like a parked car in a parking lot or coming up to another car stopped at a stop light.

3) The battery must be below 90% to correctly replicate (see number 2) and it cannot be duplicated during a routine test drive on streets or highway. They must test drive in a parking lot and attempt to park with a risk of hitting something (car or curb etc) to really trigger the sensation of not enough braking compared to amount of brake pedal imput. Rolling up to a stop sign with no one in front of you or parking in a empty double parking spot doesn't have the same urgency or risk to an overshoot and they won't understand the concern.

 

[WuffvonTrips]

when battery is at 100% the Taycan switches to 100% mechanical brakes since there is no place to put the recovered energy)

Are you sure about that? The Taycan's 100% charge is less than the capacity of the battery, and any potential braking energy recovery will typically be less than the charge consumed to get it up to speed before braking (downhill runs might be an exception).

 

[Jenner]

Are you sure about that? The Taycan's 100% charge is less than the capacity of the battery, and any potential braking energy recovery will typically be less than the charge consumed to get it up to speed before braking (downhill runs might be an exception).

100% positive this was my personal experience:

Put Taycan on charger one night and accidentally direct charge was enabled. So it didn't take my usual home charge profile of 85% and charged to 100%

Get in Taycan and drive the next morning at 100% and its like a magic fairy fixed my brakes overnight. It was INSTANTLY noticeable from the moment I set out of my garage. Nothing changed between parking except the SoC.

The braking felt close to mechanical with instant response and stopping power. I barely had to apply any pedal pressure to get deceleration. Huge contrast to the amount of pedal travel required less than 24 hours before.

As my SoC depleted the terrible brake feeling started to come back little by little.

Once my SoC went below 90% the awful brakes were fully back to how they were previously.

Also the amount of green recouperation displayed in the center gauge is barely visible when at 100% SoC. I live on top of a valley and to go into town my entire drive is downhill. My individual profile is set to always have recouperation on and I am very familiar with how much recouperation is normally displayed on the meter when going down the hill under normal battery SoC which is always 85% or less.

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