Taxdr1965

Porsche has to do something with the brakes on these cars. Absolutely horrible bordering on dangerous where it feels like the brakes are just not working , then all of a sudden kicking on. Anyone else experience this or think these brakes are rubbish

jnolan

do you have PCCB or iron brakes?

Taxdr1965

I have iron and the brake pedal fee is super squishy, keeps changing brake pressure

cometguy

It takes some getting used to, because you're mostly braking with the regenerative brakes before you get into the brake pads upon harder braking.
I've had my E-Hybrid for nearly a year now, and I'm very used to it and have no issues. When I've really needed the car to brake quickly, it does not fail me.

jnolan

yes, the regen braking requires a different style. The Porsche system is far more linear than other hybrid systems I have driven, there is no hard brake surge followed by a brake gap that requires more pressure. FWIW, I have PCCB on my hybrid and the brakes are quite nice, despite the occasional clunk.

SaratogaLefty

So I have the standard brakes on my E-Hybrid and as mentioned above it did take some getting used to but now I don't have any problem with them. It is also possible the car "learned" my driving behavior and it may have adjusted as well. I just had my first annual service and my Service Rep told me everything looks great. He mentioned my brakes are at 9mm vs 12mm new. So here is my question. My car has just over 6000 miles on it. Assuming 12mm at inception on the brakes, and now at 9mm, that implies that I've used 25% so does that mean I will need new brakes at 24,000 miles?? Is the wear linear? Does the regenerative braking increase wear on the brakes? Lastly, what does a brake job cost? Years ago I had a BMW 540i with the "Sport" setup and when I had to do a brake job they also had to replace the rotors every time. It ran about $2500 every 20,000 miles or so and that was about 15 years ago.

cometguy

Many hybrid and electric cars only need brake pads replaced every 100k miles or so, I have heard, although Porsche drivers may drive much more aggressively than the average driver. If one is not too aggressive, the vast majority of braking should be handled by the regen braking, which don't affect the brake pads. I'll be doing my 20k-mile servicing next month, and I'll inquire as to the size of my brake pads; I didn't think to ask at my 10k-mile servicing last August. I think that brake jobs on these cars is quite expensive.

CanuckGT4

Same experience i had when test driving the turbo e-hybrid, the brakes were spongy and very oddly artificial feeling.
Probably just takes some getting used to and it sounds like you have.

SaratogaLefty

Based on your statement "the vast majority of braking should be handled by the regen braking, which don't affect the brake pads" can you explain to me how the regen braking actually works??

cometguy

You can find a lot from a google search.... such as this:
"With regenerative brakes, on the other hand, the system that drives the vehicle does the majority of the braking. When the driver steps on the brake pedal of an electric or hybrid vehicle, these types of brakes put the vehicle's electric motor into reverse mode, causing it to run backwards, thus slowing the car's wheels. While running backwards, the motor also acts as an electric generator, producing electricity that's then fed into the vehicle's batteries. These types of brakes work better at certain speeds than at others. In fact, they're most effective in stop-and-go driving situations. However, hybrids and fully electric cars also have friction brakes, as a kind of back-up system in situations where regenerative braking simply won't supply enough stopping power. In these instances, it’s important for drivers to be aware of the fact that the brake pedal might respond differently to pressure. The pedal will sometimes depress farther towards the floor than it normally does and this sensation can cause momentary panic in drivers."

"In addition, using the motor/generator for braking reduces brake wear and the buildup of brake dust.

In many situations, the motor/generator’s braking power is sufficient to slow the vehicle. As a result, the conventional braking system receives less use. However, during very rapid deceleration, at very low speeds or when the vehicle is stationary, the motor/generator can’t produce the necessary braking force to slow or stop the vehicle.

The motor/generator’s braking potential is dependent on vehicle speed. At low speeds, maximum brake torque is available. At high speeds or very low speeds (just before coming to a stop), sufficient brake torque can’t be provided, meaning the conventional braking system must be activated. Motor/generator brake torque is proportional to the motor/generator’s output and is also influenced by the high-voltage battery’s state-of-charge. Brake torque from the motor/generator is available only when the high-voltage battery is not fully charged.

With the motor/generator doing some or all of a vehicle’s braking on a hybrid or electric vehicle, what effects will this have on the conventional hydraulic brake system? If a vehicle of this type is driven primarily in an urban environment where speeds are low and the required braking force is also relatively low, extra-long brake pad life is sure to be one measurable and not unwelcome effect."

SaratogaLefty

Okay, that explains it very well and also maybe why I'm seeing some wear. Most of my driving is on the freeway or local highways so very little stop and go at slow speeds. I do manage to use the electric mode for most of my trips as they tend to be around 20-24 miles total distance but most of my driving is between 50 and 75 mph. I have also done some mountain road driving for sporty fun but again at speed and using the brakes hard at times to adjust for curves.

louver

I agree with most of what has been said about regen braking but would point out the variability of driving habits. If you tend to apply the brakes smoothly and gently, then you will get mostly regenerative braking. On the other hand, if you tend to punch the brakes hard, then you may get more friction braking and less regen. The row of little green lights under the tach indicate how much regen you are getting at the moment, so you can train yourself. As in other aspects of driving, there is some tension between fun and efficiency.

SaratogaLefty

Even when I put the brakes on hard the green lights lite up all the way.

cometguy

Yes, I think that regen braking with energy generation is present whenever you're down to brake pads.
As for having fun: I think it's a matter of good driving, as to how much you use brake pads, not fun. I have tons of fun driving my Porsches, but I'm super-attentive to the surroundings, so that I don't have to slam on my brakes very often; I tend to lay off the accelerator pedal when in heavy traffic or near intersections. I'm also probably among the top 5% on the road in terms of speed, most of the time, but I don't tailgate and don't weave in and out of traffic much. The fun for me comes from just being in my Porsche, first, and then when I'm able to open it up on wide-open roads, second. :-)

SaratogaLefty

I also drive very conservatively when in traffic or on the freeway. However, when I'm driving aggressively on mountain roads I do accelerate and brake hard (safely). I had a 911 that I tracked for five years and I very much enjoy twisty mountain roads.