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Consolidated Macan Brembo upgrade thread (READ FIRST POST)

burgerkong

Go Kart Champion
Location
Ontario, Canadeh
diameter....thanks for that confirmation.

what about length of piston? (it's probably 30 or 32 mm)

1611166032277.png


Courtesy of a post in @emichel6888 's thread.
 

scrapin240

Drag Racing Champion
Location
IzzaGolf
Car(s)
Golf
So I was reaching out to Zeckhausen Racing to get the Ferodo DS3.12 for the OEM calipers, and told him that I was switching from Macan back to the OEM, and he asked if it was a race series issue or something else. Dave was super and has tons of information, and knows all things brakes.
He said that the master cylinder should be sufficient:

The stock MKVII caliper uses a single 60mm piston. That yields an effective piston area of 5655 mm^2. (multiply by two when the caliper is floating)

The 2015-17 Macon Base with 345mm front rotors uses calipers with four 42mm pistons, giving it an effective piston area of 5542 mm^2, or 98% of stock. That's close enough to be insignificant.

This should mean the brake torque output of your Porsche caliper upgrade would be 2% less than stock, but the stiffness of 4-piston fixed vs single-piston floater more than makes up the difference because of higher caliper efficiency converting hydraulic pressure into clamping force. The single piston caliper flexes way more, which wastes energy.

So I'm trying to understand why you had problems. Was 42mm the actual piston diameter of the Porsche calipers you had? Or something else? Was pedal travel longer, shorter, or the same as stock?
I told him about the issues that track users faced, such as initial brake pedal issues, and he said

That's a pad knockback issue. As you go through turns or hit the kerbing the front wheel bearings are deflecting. This deflection causes the rotor to deflect by the same angular amount. But when you are all the way to the outer edge of the rotor, that angular deflection turns into some significant axial deflection, which pushes the pads away from the rotors. The next application of the brake pedal has to close this gap, which is why you experience initial pedal travel without any braking.

If you were to gently tap the pedal with your left foot, just prior to when you actually need to hit the brakes, then you would find the pedal rock hard when you needed it. Alternatively, you could install StopTech pistons and anti-knockback springs in the Porsche calipers and eliminate the problem. The reason for the StopTech pistons is that they have a machined feature on the bottom that engages with the spring.
The solution looks like this.
1611173278504.png


He then suggested
the shortest pistons we have that support both dust boots AND knockback springs are 29.5mm. However, you could have a machine shop mill the bottoms of the OEM pistons for you. This is what it would look like:

So, the pistons that work have the shortest length of 29.5mm, so if that diagram is correct, the stock ones are too short. If someone can confirm the measurements that would be great. Otherwise I will be going back to stock in the upcoming weeks, and will try then to measure. His gut feeling is that they are 30mm, but we would need to get an actual measurement to know.


1611173435248.png


If the piston length is shorter than 29.5 and is machined, the springs to use are 8 of these:
https://www.zeckhausen.com/catalog/product_info.php?products_id=22044

This is the first time someone with some braking knowledge even tried to explain these issues. Sounds very interesting and would love to see if it solves the problem. Edit: There is a warning on the page that it can accelerate wear on pads, so that is something else to be aware of. This depends on the spring rate used. Dave said the .4in should not drag the brakes in a daily, and .6in could be used in a track car with severe knockback and should not drag the brakes in either case.

I would reach out to Dave and Zeckhausen racing for any braking needs/information in the future.
 
Last edited:

GTIfan99

Autocross Champion
Location
FL
My car is a street car, so definite no go. I'll just tap brake like I did with my STI.
 

scrapin240

Drag Racing Champion
Location
IzzaGolf
Car(s)
Golf
My car is a street car, so definite no go. I'll just tap brake like I did with my STI.
I edited my response. There are various spring rates available. Dave said the .4in should not drag the brakes in a daily, and .6in could be used in a track car with severe knockback and should not drag the brakes in either case.
 

GTIfan99

Autocross Champion
Location
FL
I edited my response. There are various spring rates available. Dave said the .4in should not drag the brakes in a daily, and .6in could be used in a track car with severe knockback and should not drag the brakes in either case.
I'd be in for a setup that didn't drag.
 

GTIfan99

Autocross Champion
Location
FL
Based on that diagram, 27.2.
 

burgerkong

Go Kart Champion
Location
Ontario, Canadeh
So I was reaching out to Zeckhausen Racing to get the Ferodo DS3.12 for the OEM calipers, and told him that I was switching from Macan back to the OEM, and he asked if it was a race series issue or something else. Dave was super and has tons of information, and knows all things brakes.
He said that the master cylinder should be sufficient:


I told him about the issues that track users faced, such as initial brake pedal issues, and he said


The solution looks like this.
View attachment 200618

He then suggested


So, the pistons that work have the shortest length of 29.5mm, so if that diagram is correct, the stock ones are too short. If someone can confirm the measurements that would be great. Otherwise I will be going back to stock in the upcoming weeks, and will try then to measure. His gut feeling is that they are 30mm, but we would need to get an actual measurement to know.


View attachment 200619

If the piston length is shorter than 29.5 and is machined, the springs to use are 8 of these:
https://www.zeckhausen.com/catalog/product_info.php?products_id=22044

This is the first time someone with some braking knowledge even tried to explain these issues. Sounds very interesting and would love to see if it solves the problem. Edit: There is a warning on the page that it can accelerate wear on pads, so that is something else to be aware of. This depends on the spring rate used. Dave said the .4in should not drag the brakes in a daily, and .6in could be used in a track car with severe knockback and should not drag the brakes in either case.

I would reach out to Dave and Zeckhausen racing for any braking needs/information in the future.

Except that's not true lol, noone here is specifically getting knockback on the street (particularly since most, if not all, are still utilizing one-piece rotors vs 2 piece floating rotors which exacerbate knockback). If this was the case, the stock floating calipers would be even worse as it moves around significantly more. Long story short, what he told you factually isn't wrong, but not particularly applicable to this setup (Macan/Q5/TTS) looking at specific cases of where brake issues (soft pedal, longer pedal travel, inconsistent braking performance) have occurred. I guess what I am trying to say is that all the aforementioned issues happened after the caliper swap, which points to a caliper compatibility issue - looking at it a different way, there aren't reports of Macan/Q5 drivers having problems like we're seeing.

The Macan/Q5 M/C piston is about 10% bigger than most GTI's/R's, which is a fact. We have also discovered VW/VAG made a small change and potentially upgraded and specced a larger M/C (to match the Macan/Q5 diameter of 25.4mm) for later models (7.5 and up looks like).

While knockback springs do work, considering there are other factors at play I'm not going to automatically assume and conclude/throw money and parts into solutions that may not even address the core problem but rather act as a bandaid.
 

scrapin240

Drag Racing Champion
Location
IzzaGolf
Car(s)
Golf
Except that's not true lol, noone here is specifically getting knockback on the street (particularly since most, if not all, are still utilizing one-piece rotors vs 2 piece floating rotors which exacerbate knockback). If this was the case, the stock floating calipers would be even worse as it moves around significantly more. Long story short, what he told you factually isn't wrong, but not particularly applicable to this setup (Macan/Q5/TTS) looking at specific cases of where brake issues (soft pedal, longer pedal travel, inconsistent braking performance) have occurred. I guess what I am trying to say is that all the aforementioned issues happened after the caliper swap, which points to a caliper compatibility issue - looking at it a different way, there aren't reports of Macan/Q5 drivers having problems like we're seeing.

The Macan/Q5 M/C piston is about 10% bigger than most GTI's/R's, which is a fact. We have also discovered VW/VAG made a small change and potentially upgraded and specced a larger M/C (to match the Macan/Q5 diameter of 25.4mm) for later models (7.5 and up looks like).

While knockback springs do work, considering there are other factors at play I'm not going to automatically assume and conclude/throw money and parts into solutions that may not even address the core problem but rather act as a bandaid.
I have a '19 7.5 R and had the same issue, so don't think it's a larger MC
 

GTIfan99

Autocross Champion
Location
FL

GTIfan99

Autocross Champion
Location
FL
Except that's not true lol, noone here is specifically getting knockback on the street (particularly since most, if not all, are still utilizing one-piece rotors vs 2 piece floating rotors which exacerbate knockback). If this was the case, the stock floating calipers would be even worse as it moves around significantly more. Long story short, what he told you factually isn't wrong, but not particularly applicable to this setup (Macan/Q5/TTS) looking at specific cases of where brake issues (soft pedal, longer pedal travel, inconsistent braking performance) have occurred. I guess what I am trying to say is that all the aforementioned issues happened after the caliper swap, which points to a caliper compatibility issue - looking at it a different way, there aren't reports of Macan/Q5 drivers having problems like we're seeing.

The Macan/Q5 M/C piston is about 10% bigger than most GTI's/R's, which is a fact. We have also discovered VW/VAG made a small change and potentially upgraded and specced a larger M/C (to match the Macan/Q5 diameter of 25.4mm) for later models (7.5 and up looks like).

While knockback springs do work, considering there are other factors at play I'm not going to automatically assume and conclude/throw money and parts into solutions that may not even address the core problem but rather act as a bandaid.
Meh, I'd be fine with a bandaid if it works.
 
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