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Initial Observations on the Performance of Neuspeed BBK in Track-Day Environment

scrllock

Passed Driver's Ed
Location
MI
Not everyone wants to add one more spot that a leak can creep in, particularly not in something as critical for safety as the braking system...
 

GTIfan99

Autocross Champion
Location
FL
Give that man a prize!
Shop performed more bleeds. I had them install SS lines on the rear brakes. Things might be slightly better, not a dramatic improvement I had hoped for. No one thinks the MC needs replacement.

The shop had installed a RS3 MC for a customer, but it didn't seem to match up with the system. It was ultimately removed. So that approach doesn’t seem viable.

So I think I’m at the end of the line. At this point, maybe the problem is between my ears.

I did a 29 psi bleed in the VW order, then bleed both front simultaneously, changed to RBF660 fluid, lubed pistons with Castrol red rubber grease, and did the OBD 11 coding detailed in the Macan caliper thread. They are as good as stock now. Mine felt just like you're describing yours to now before I started optimizing my setup, which is the Macan calipers.

I didn't do the valves as mentioned, I just didn't want anothrr failure point. Plus, everything I did I was able to do myself with the tools and skills I already have.
 

GTIfan99

Autocross Champion
Location
FL
Not everyone wants to add one more spot that a leak can creep in, particularly not in something as critical for safety as the braking system...

That's exactly why I kept going until I got a good pedal feel without using them. It's possible.
 

emichel6888

Go Kart Champion
Location
TX
Not everyone wants to add one more spot that a leak can creep in, particularly not in something as critical for safety as the braking system...

:giggle: I am curious, how do you imagine a "leak can creep in"? Do you think the metal fittings will spontaneously loosen or crack? Some sort of spontaneous metal fatigue? If that is the case, are you also worried about the existing large number of identical fittings throughout the brake system? Those were installed by some random factory worker, I am sure they would take far more care than you would on your own car, right?
The fact is the highest potential failure point is the flex lines, and even that is extremely remote. Our entire brake system is held together by a rubber (or nylon) hose attached with a compression fitting, do you live in fear that it will spontaneously fail at any moment?

I know for some it is a concern, but if extremely remote possibilities are that important to you, then I don't know how you ever venture out of your basement.
 

emichel6888

Go Kart Champion
Location
TX
That's exactly why I kept going until I got a good pedal feel without using them. It's possible.
Yes that will get you similar stock caliper pedal characteristics, but good is a relative term. I guess if you don't know what you are missing then...
 

scrllock

Passed Driver's Ed
Location
MI
If you're a trained factory worker whose job it is do assemble that piece, I'd wager you're a lot more familiar with how they should be installed than some random amateur mechanic.
The RPV clearly works for you, great! But most people should and will prefer a simpler solution without adding another failure point. Basic engineering principles.
 

burgerkong

Go Kart Champion
Location
Ontario, Canadeh
The Macan/Q5 calipers piston displacement is not a mismatch (for the Golf R/PP brakes), they are actually very close to the stock caliper displacement. The issue with pedal height is caused by the increased amount of piston retraction. If you have air trapped in your system the manual says to use a pressure bleeder at 30 PSI and bleed both front calipers at the same time. I have used this method and it seems to work well.

Wrong. We've already established how the Q5/Macan uses a M/C that is 10% bigger than the MQB cars. You know you're really butt sore because people aren't listening to you trying to peddle your RPV mods lmao.

Why is it so difficult to comprehend people's decision to not modify the brake lines and install a dubious device? I know you've invested countless time and energy into it, only to get ignored. Grow up, you can't force people to agree with you.
 

jmason

Go Kart Newbie
Location
Frederick, MD
It is my understanding that the seal grease and RPV mod are intended to reduce the piston retraction and thereby reduce pedal travel to engagement. This is not the issue I am trying address. The issue I am trying to address is one where the pedal will stink to the floorboard if you press on the pedal very firmly for a long time. It is my belief that the pressure on the pedal to press it to the floorboard is less than it should be. Again, seal grease and RPV will not address this issue.

Just for discussion, were I to put on the seal grease and install RPVs, the engagement point would be nearly instantaneous, and the outer front pads would drag on the rotor more than they already do. The engagement point would be too high for easy heel-and-toe.

I am trying to understand where the compliance is that is allowing me to press the pedal to the floor. One cause may be air is still in the system. I think I have tried everything to eliminate that as a cause. Another potential cause is fluid leakage past the MC seals. I have performed bleed down tests in accordance with VW factory manuals. The results of those tests did not indicate loss of pressure, so I think I can eliminate a defective MC or fluid leaks. No leaks have been observed. There could be something associated with the ABS. However, I don't have a good enough understanding of the details of the VW system design to be able to identify an element that could be the cause of the problem.
 
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burgerkong

Go Kart Champion
Location
Ontario, Canadeh
It is my understanding that the seal grease and RPV mod are intended to reduce the piston retraction and thereby reduce pedal travel to engagement. This is not the issue I am trying address. The issue I am trying to address is one where the pedal will stink to the floorboard if you press on the pedal very firmly for a long time. It is my belief that the pressure on the pedal to press it to the floorboard is less than it should be. Again, seal grease and RPV will not address this issue.

Just for discussion, were I to put on the seal grease and install RPVs, the engagement point would be nearly instantaneous, and the outer front pads would drag on the rotor more than they already do. The engagement point would be too high for easy heel-and-toe.

I am trying to understand where the compliance is that is allowing me to press the pedal to the floor. One cause may be air is still in the system. I think I have tried everything to eliminate that as a cause. Another potential cause is fluid leakage past the MC seals. I have performed bleed down tests in accordance with VW factory manuals. The results of those tests did not indicate loss of pressure, so I think I can eliminate a defective MC or fluid leaks. No leaks have been observed. There could be something associated with the ABS. However, I don't have a good enough understanding of the details of the VW system design to be able to identify a an element that could be the cause of the problem.

The brake fluid reservoir cap actually releases pressure as it's not a tight seal, so there's one source. Plus M/C movement under braking as well.
 

jmason

Go Kart Newbie
Location
Frederick, MD
The brake fluid reservoir cap actually releases pressure as it's not a tight seal, so there's one source. Plus M/C movement under braking as well.
I wouldn't think the reservoir to open to the high pressure side of the brake hydraulics. Pressing the brake pedal creates pressure exceeding 70 bar, at least that is the pressure in the system for conducting the bleed down test. It is likely higher than that. I think the reservoir is open to the atmosphere to allow brake fluid to flow into the MC as needed (in response to pad wear) when the brake pedal is not pressed. That is why when you open the brake hydraulic components, you can partially engage the brake pedal to close the system to the atmosphere and prevent brake fluid from draining out of the open connection.

It's likely there is some MC movement. I have no idea if it is sufficient to cause the issue I'm addressing. Doesn't seem like it, but I can't discount it either.
 

GTIfan99

Autocross Champion
Location
FL
It is my understanding that the seal grease and RPV mod are intended to reduce the piston retraction and thereby reduce pedal travel to engagement. This is not the issue I am trying address. The issue I am trying to address is one where the pedal will stink to the floorboard if you press on the pedal very firmly for a long time. It is my belief that the pressure on the pedal to press it to the floorboard is less than it should be. Again, seal grease and RPV will not address this issue.

Just for discussion, were I to put on the seal grease and install RPVs, the engagement point would be nearly instantaneous, and the outer front pads would drag on the rotor more than they already do. The engagement point would be too high for easy heel-and-toe.

I am trying to understand where the compliance is that is allowing me to press the pedal to the floor. One cause may be air is still in the system. I think I have tried everything to eliminate that as a cause. Another potential cause is fluid leakage past the MC seals. I have performed bleed down tests in accordance with VW factory manuals. The results of those tests did not indicate loss of pressure, so I think I can eliminate a defective MC or fluid leaks. No leaks have been observed. There could be something associated with the ABS. However, I don't have a good enough understanding of the details of the VW system design to be able to identify an element that could be the cause of the problem.

It does that stock too. Likely caused by the abs system.

I promise the red rubber grease, proper bleed, good fluid and the abs tweaks improve the overall feel.
 

jmason

Go Kart Newbie
Location
Frederick, MD
It does that stock too. Likely caused by the abs system.

I promise the red rubber grease, proper bleed, good fluid and the abs tweaks improve the overall feel.
The only bleed technique I haven’t tried is simultaneously bleeding both front brakes. Otherwise, I don’t know what additional bleeding I could do. I have entered the brake adaptions. I didn’t think there was any difference in feel with the car standing still. I still don’t understand how the seal grease would solve my problem. I’m just dense I guess. I’m using ATE 200 fluid. Never have had an issue.
 

GTIfan99

Autocross Champion
Location
FL
The only bleed technique I haven’t tried is simultaneously bleeding both front brakes. Otherwise, I don’t know what additional bleeding I could do. I have entered the brake adaptions. I didn’t think there was any difference in feel with the car standing still. I still don’t understand how the seal grease would solve my problem. I’m just dense I guess. I’m using ATE 200 fluid. Never have had an issue.

ATE 200 is not compatible with our brake system.
 
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jmason

Go Kart Newbie
Location
Frederick, MD

emichel6888

Go Kart Champion
Location
TX
It is my understanding that the seal grease and RPV mod are intended to reduce the piston retraction and thereby reduce pedal travel to engagement. This is not the issue I am trying address. The issue I am trying to address is one where the pedal will stink to the floorboard if you press on the pedal very firmly for a long time. It is my belief that the pressure on the pedal to press it to the floorboard is less than it should be. Again, seal grease and RPV will not address this issue.

Just for discussion, were I to put on the seal grease and install RPVs, the engagement point would be nearly instantaneous, and the outer front pads would drag on the rotor more than they already do. The engagement point would be too high for easy heel-and-toe.

I am trying to understand where the compliance is that is allowing me to press the pedal to the floor. One cause may be air is still in the system. I think I have tried everything to eliminate that as a cause. Another potential cause is fluid leakage past the MC seals. I have performed bleed down tests in accordance with VW factory manuals. The results of those tests did not indicate loss of pressure, so I think I can eliminate a defective MC or fluid leaks. No leaks have been observed. There could be something associated with the ABS. However, I don't have a good enough understanding of the details of the VW system design to be able to identify an element that could be the cause of the problem.

Your outer pad is already dragging? That should not happen, are you sure?

What you are describing (sitting and standing on the brake pedal and it slowly sinks) that happens to all, even with the stock caliper. It has to do with the two step MC and the ECU power assist causing a huge increase in pressure vs pedal effort. I can't say for sure with your calipers, but I can say for certain with the Macan/Q5 caliper those mods do prevent this from happening. I explain why in the post (with a diagram). There is nothing dubious about using RPV's, they have been used in countless street and track applications for decades.
There is no other larger MC options for this car, and other than going to a different caliper (like the ST40), there does not appear to be any other way to improve it. As the original guinea pig now with thousands of hard street and track miles, it works and is perfectly safe.
The only thing I am butt hurt about is the fact that no one mentioned the brake pedal issue before I spent the time and money to upgrade to these calipers. The issue was very apparent from my first test drive, then I find that everyone noticed it but did not want to talk about it (why I still don't understand), but great thanks.
The stock system has a lot of intentional slop in it because VW is using the ECU to actuate the brakes for you. If you don't like that because it makes it difficult to modulate the brakes under track conditions you can turn off some of the ECU assist, but then you are left with a lot of unnecessary and unwanted pedal slop.

The modifications I did go a long way towards fixing that slop, and it has to do with the two step MC I show and talk about in my post. I did this to fix this issue for myself, and I did. You post telling us you are having the same issue and I am just trying to help. I would not describe myself as "butt hurt" just perplexed when I am the only one here who admits to having the same issue and has found a working solution.

You can learn to live with it (apparently that is what most have decided to do), or try my recommendation, or get a different caliper. The only one that reportedly does not suffer from this same issue is the ST40, and I believe it is because they have a significantly smaller piston displacement (almost 25% smaller). I bet that also keeps the MC in stage one, that combined with the smaller MC/caliper ratio I am sure give a very high and firm brake pedal. If I was going to spend $3-4K on a brake upgrade, that is the one I would get.

This is supposed to be just for fun, and arguing with arm chair engineers is not my idea of fun, so good luck.
 
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