Model S Plaid Brakes Are Terrible!

[Gninoked]

So you are recommending to just purchase the aftermarket pads to see what type of improvements, if any before investing that much money for the kit?

I would like to see someone try this too - from MPP/our experience and testing so far it would seem that probably a more "performance" oriented pad (vs the comfort oriented stock pad) will likely be enough for most owners who simply want more aggressive stops on the street (at a slight loss of single pedal mode comfort, dust, etc.)

That is *not* enough for road course use though given the speeds and weight of these cars. For that the question is what combination of additional pad mu, capacity and cooling is needed - either wait for more results to come in, or take a leap and participate on the testing to find out!

 

[Trompazo]

I would like to see someone try this too - from MPP/our experience and testing so far it would seem that probably a more "performance" oriented pad (vs the comfort oriented stock pad) will likely be enough for most owners who simply want more aggressive stops on the street (at a slight loss of single pedal mode comfort, dust, etc.)

That is *not* enough for road course use though given the speeds and weight of these cars. For that the question is what combination of additional pad mu, capacity and cooling is needed - either wait for more results to come in, or take a leap and participate on the testing to find out!

I have the racing brake pads, and plan to do the spring mod that MPP posted about.

But where I am in Canada, is now -20 Celsius with snow on the road, so not a high priority. Likely within the next 2 weeks.

 

[MFrunkerOG]

Got an update from UP. My front and rear sets should be getting here mid to late Jan.

Ho hum! Now to stay alive until then!

 

[Mash]

So you are recommending to just purchase the aftermarket pads to see what type of improvements, if any before investing that much money for the kit?

I think it would mostly fix the problem of brake feel for street use. Stock rotors are not great, but they kinda work. It's quite obvious that pad just melts, though. But you're not winning much by changing stock rotors to almost same size CCB - CCB ventilates even worse, at the same size has much lower heat capacity. The only advantage over stock would be much less dust, but temperature is going to be worse than stock rotors with more heat tolerant pads.

If mid temp (970) pads won't be enough to not overheat - you have to go with brake ducts or/and largest possible decent rotors with larger calipers and pads.

Pads+fluid+pad spring mod. Overheats -> ducts. Still overheats -> largest available proven BBK with steel rotors...

 

[Duke846]

I think it would mostly fix the problem of brake feel for street use.

I have posted this earlier. Tesla has changed the ibooster on the Plaid. That definitely will improve brake feel.
looks like they changed it on cars made in November.

 

[Mash]

I have posted this earlier. Tesla has changed the ibooster on the Plaid. That definitely will improve brake feel.
looks like they changed it on cars made in November.

Sorry, I missed that. Did they change the HW model? Anyway, with higher friction pads you need less work from the booster.

 

[MFrunkerOG]

Sorry, I missed that. Did they change the HW model? Anyway, with higher friction pads you need less work from the booster.

I spoke to the service folks. They were unaware of the change.

But then they also said that the Plaid has the best brakes. So…

 

[Duke846]

I spoke to the service folks. They were unaware of the change.

But then they also said that the Plaid has the best brakes. So…

Part number has changed.
Your SC straight up lied to you. Tesla made a change to the Ibooster. This is public information.
I will help a little.

Parts Catalog

epc.tesla.com

You can check the part number on your vehicle to match this.

 

[MountainPass]

Hey guys,

Just a little self-centered update for you all from MPP:

Happy to announce that our first batch of 400MM big brake kits will be shipping out directly from Girodisc this week, ahead of schedule! So if you haven't already made an order and want a pair before the holiday break, now might be a good time

The 2pc rear rotors and OEM fronts are coming along as well and we should have prototypes of those here early next week.

The master cylinder brace has been awesome, the amount that the OE firewall flexes is quite significant. We'll do a test and post it to show just how much the firewall flexes. It is certainly contributing to that long pedal feel that the car has (especially with the low friction OEM pads that require a lot of effort). We're looking for beta testers of the MC brace, so if you're interested shoot us a PM or an email. We want to average out dimensions over a number of vehicles.

In addition, we've been prototyping lines, so that is something in the pipeline that will be released in the coming months.

We're really proud to say that we've made some significant strides in the brake department on the Plaid, the pedal feel is finally up there with what you would expect with the right pads. We have some prototype pads that I can't talk too much about at the moment, but they are working quite well (as evidenced by the data below!)

Here are results from our multi-channel IR brake temp test comparing the 400mm BBK to the OE rotor, both sides using the same prototype pads. The significant thing to note is how much cooler the MPP rotor runs over the duration of the test, this is because once the OEM rotor heat soaks, it takes much longer for it to cool down.

A description of the graphs above:

Top: A rainbow chart of the MPP 400MM rotor (Brake Temp Left Sensors 1-6). The top of the graph indicates the outside of the rotor, and the bottom of the graph indicates the inside of the rotor. You can observe that the inside always runs cooler because that is where the cool air enters the center vanes. This is evidence of the air being pumped through the rotor.

The range of the color graph is 150C (dark blue) to 850C (dark red). Rotors can be seen glowing at ~520C in the day - so wherever you see yellow-red in the graph above, the rotors were glowing!

Middle: A rainbow chart of the OEM 380mm rotor (Brake Temp Right Sensors 1-6). The rotor heats evenly over the surface and retains its heat much longer as it does not have a way to actively cool itself.

Lower: Vehicle speed to help you understand the drive cycle. Full throttle acceleration between 80-150km/h repeatedly, specifically in the latter part of the test. Acceleration Longitudinal Car is zoomed in to the range of -0.8 to 1.4G's of braking. The green horizontal line indicates 1G of braking, so you can easily observe how aggressive the braking events were. Specifically, at the end, these were all full ABS braking applications.

So other than looking awesome, the rotors make a very significant improvement to helping the brake system run cooler as we claimed.

 

[MFrunkerOG]

Part number has changed.
Your SC straight up lied to you. Tesla made a change to the Ibooster. This is public information.
I will help a little.

Parts Catalog

epc.tesla.com

You can check the part number on your vehicle to match this.

i wish there were an old vs new comparison. anyone got the old part number screenshot?

 

[Duke846]

i wish there were an old vs new comparison. anyone got the old part number screenshot?

1044671-00-C old part number
1420671-00-A new November build and newer.

 

[Duke846]

i wish there were an old vs new comparison. anyone got the old part number screenshot?

I will make a YT video for everyone.

 

[MFrunkerOG]

I will make a YT video for everyone.

Which car will you use?

 

[Duke846]

Which car will you use?

Plaid 2022
should have the new booster.
not mine, friend, I choose to wait for the roadster and see how many miles I can rack up on my performance 3.

 

[Mash]

Hey guys,

Just a little self-centered update for you all from MPP:

Happy to announce that our first batch of 400MM big brake kits will be shipping out directly from Girodisc this week, ahead of schedule! So if you haven't already made an order and want a pair before the holiday break, now might be a good time

The 2pc rear rotors and OEM fronts are coming along as well and we should have prototypes of those here early next week.

The master cylinder brace has been awesome, the amount that the OE firewall flexes is quite significant. We'll do a test and post it to show just how much the firewall flexes. It is certainly contributing to that long pedal feel that the car has (especially with the low friction OEM pads that require a lot of effort). We're looking for beta testers of the MC brace, so if you're interested shoot us a PM or an email. We want to average out dimensions over a number of vehicles.

In addition, we've been prototyping lines, so that is something in the pipeline that will be released in the coming months.

We're really proud to say that we've made some significant strides in the brake department on the Plaid, the pedal feel is finally up there with what you would expect with the right pads. We have some prototype pads that I can't talk too much about at the moment, but they are working quite well (as evidenced by the data below!)

Here are results from our multi-channel IR brake temp test comparing the 400mm BBK to the OE rotor, both sides using the same prototype pads. The significant thing to note is how much cooler the MPP rotor runs over the duration of the test, this is because once the OEM rotor heat soaks, it takes much longer for it to cool down.

View attachment 746652

A description of the graphs above:

Top: A rainbow chart of the MPP 400MM rotor (Brake Temp Left Sensors 1-6). The top of the graph indicates the outside of the rotor, and the bottom of the graph indicates the inside of the rotor. You can observe that the inside always runs cooler because that is where the cool air enters the center vanes. This is evidence of the air being pumped through the rotor.

The range of the color graph is 150C (dark blue) to 850C (dark red). Rotors can be seen glowing at ~520C in the day - so wherever you see yellow-red in the graph above, the rotors were glowing!

Middle: A rainbow chart of the OEM 380mm rotor (Brake Temp Right Sensors 1-6). The rotor heats evenly over the surface and retains its heat much longer as it does not have a way to actively cool itself.

Lower: Vehicle speed to help you understand the drive cycle. Full throttle acceleration between 80-150km/h repeatedly, specifically in the latter part of the test. Acceleration Longitudinal Car is zoomed in to the range of -0.8 to 1.4G's of braking. The green horizontal line indicates 1G of braking, so you can easily observe how aggressive the braking events were. Specifically, at the end, these were all full ABS braking applications.

So other than looking awesome, the rotors make a very significant improvement to helping the brake system run cooler as we claimed.

Finally, real proper data. Thank you.

If I'm reading it right - if there was a passenger in the car - he got really dizzy. Rotor temps are not as bad as I thought, but your rotor clearly ventilates better and has more heat capacity.

To make that test even better, I would put a thermocouple in brake bleeders to check how heat transfers to brake fluid. Because that's what puts you in the wall.

 

[DennisP]

Finally, real proper data. Thank you.

If I'm reading it right - if there was a passenger in the car - he got really dizzy. Rotor temps are not as bad as I thought, but your rotor clearly ventilates better and has more heat capacity.

To make that test even better, I would put a thermocouple in brake bleeders to check how heat transfers to brake fluid. Because that's what puts you in the wall.

Following these forums helps me a lot

 

[smoking81]

This guy and MPP above say that Carbon Brakes are much better. Why would you not use them on the track? If the car stops faster and has less brake fade then what is the down side? Less rotational mass should also need less energy to slow down. Is there any real world data that shows the carbon brakes not working on a track?

 

[MarcG]

This guy and MPP above say that Carbon Brakes are much better. Why would you not use them on the track? If the car stops faster and has less brake fade then what is the down side? Less rotational mass should also need less energy to slow down. Is there any real world data that shows the carbon brakes not working on a track?

I believe they have to be hot enough to work well, so doing some hard braking during a warm-up lap would be necessary to get better braking performance than steel rotors. Which means they probably won’t work best on the street when brakes are still cool. Price is another downside. For dual-purpose use, I would just stick to steel rotors.

 

[MountainPass]

Being honest - I am not an expert in carbon-ceramic brakes, but I've always understood the real benefit of them to be weight reduction. As Mash said, they dissipate heat less effectively than iron brakes, so cooling is more of a challenge, especially with high-power vehicles.

They are also much more expensive. On a 5000lb car, I fail to see the benefit of carbon brakes. The percentage weight reduction is just so small for the upfront and running costs.

They do not stop shorter (that is limited by the tire grip and ABS programming), and they do not fade less (compared to an optimized iron setup)

I have to agree with MarcG that it makes sense to stick to Iron!

 

[Mash]

They just 5-10 times more expensive for 2-3 times longer life. So if you go on track a lot - it's not good from budget perspective.

Also, they have lower convection performance (since they are lower density and it's actually hard to form venting channels in CCB rotors) to cool down between applications. That basically means that average rotor temperature would be higher.

Also they have lower heat capacity (weight is lower) that you need to have a heat energy buffer during single application.

Hotter rotors end up heating pads more although convection from rotor to pad is slower on ccb, but infrared radiation starts to be an issue with very high rotor temperature.

Positives are - less dust, lower unsprung and rotational mass, no rust. So CCB is better for street if money is not an issue. Relatively modern CCB don't have cold temperature problem. High temp pads, whether for iron or for CCB, have lower friction when cold (unless it's some high cost sintered metal pads), but still higher friction than what Tesla uses.

Since Plaid is heavy - it uses more energy to go through the same lap with the same speed. But it also can go much faster on that lap since it's capable of much higher average power than normal cars - hence even more energy.

Most of that energy needs to be radiated and convected by brakes to the air (smaller portion by tires to the pavement and air + by general air resistance + regen recuperation).

It would have to be much larger CCB rotors vs steel and you don't want to go with large wheels on the track - you need a sidewall.

So all in all - CCB is not a better choice than iron for the track.

Now if money is not a problem and you can have proper forced air rotors cooling, CCB might become good enough. And you get an advantage of lower dust, no rust and better suspension performance.