Brembo brake upgrade - Master Cylinder.

Discussion in 'Suspension, Brakes & Chassis' started by 2015Etrac, Apr 17, 2018.

  1. 2015Etrac

    2015Etrac Well-Known Member

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    I know this topic has been talked about multiple times, however, it seemed like the consensus was that the base master cylinder could be kept and worked fine? According to a new video by Vorshlag that's not the case. They said after upgrading from the base 4 piston brakes to the 6 piston Brembos, the car was terrible and would not stop right on the track. Can anyone who has done the upgrade and tracked the car confirm this? I was hoping I could just swap out the calipers and rotors.
     
  2. Houston Kid

    Houston Kid Well-Known Member

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    I’ve done the swap. The brakes are awesome. I have not tracked it but I drive the piss out of it and use the brakes. It’s my weekend drive hard and fast everywhere car. I beat on it every time I drive it. Braking late and hard. I have zero concerns. Pic here.

    Don’t ever buy one of my used cars if I’ve had it any length of time. I’m hard on them. Maintenance is 100% kept up to date but rode hard and put up wet comes to mind.

    https://www.mustang6g.com/forums/showthread.php?t=101674&page=2
     
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  3. OP
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    2015Etrac

    2015Etrac Well-Known Member

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    Haha. Good to know since I really don't feel like having to buy and swap all those additional parts. The brakes look great on your car. I plan to go with the gloss black version also. It seems like they must have had another issue other than the master cylinder/booster. In the video the guy said he was flooring the brakes and the car wasn't wanting to stop coming into the turns. I believe the explanation was the PP brakes have 9% more surface area which is "significant hydraulically" and "there's no way the base master cylinder will work".
     
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  4. ForYourOwnGood

    ForYourOwnGood Well-Known Member

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    I think they just didn't want to admit they didn't get all the air out of the system :D
     
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  5. OP
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    2015Etrac

    2015Etrac Well-Known Member

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    LOL, That's one possibility. In the video they claimed that they where almost standing on the brake pedal to get it to stop and it still was not stopping properly at the track. From everything I've seen on this site, the stock master cylinder works fine with the PP brakes. They did say the brakes worked OK for autocross, the issue was on the track. Has anyone had any track time with the upgraded PP brakes and standard master cylinder? Maybe it's only an issue that appears on the track?
     
  6. BmacIL

    BmacIL Enginerd

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    This. I call bullsh!t. The master cylinder for PP brembos would, if anything, have a slightly increased bias to the rear. Putting the brembos on a base car would keep it heavily front biased and let the more powerful fronts do work. It certainly wouldn't prevent it from stopping properly on track or road. Sounds like another possible example of poor bedding of pads/rotors, too.
     
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  7. Houston Kid

    Houston Kid Well-Known Member

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    As far as bedding goes I was able to follow the power stop instructions to the T. I went with Z26 pads. I did the one man bleed method with one of those $8 bottle kits from vatozone.
     
  8. DR_

    DR_ Well-Known Member

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    His next video will say they worked better but still not that good. Then he will be saying buy my $3800 solution that will destroy all others.
    I would have been a lot more impressed if they made the original 4 piston calipers work, since they are beefier than the S197 Brembos they used on their prior race cars, with different rotors and proper ducting.
     
  9. OP
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    2015Etrac

    2015Etrac Well-Known Member

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    I think you guys are right. It seems like the issue was elsewhere.
     
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  10. re-rx7

    re-rx7 Ruck the night away

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    Vorshlag is a well known company. He praises the OE brembos. However, im sure all the air was out of the system. These guys are pros and hold alot of records. Could be yall arent pushing the brakes hard enough to see the effects of the MC being the wrong size.
     
  11. Houston Kid

    Houston Kid Well-Known Member

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    Possibly. I report back after my first track day but I do push the car very hard for extended periods. Some that ride with me in Mexico say I thought you could only drive like that on a track.
     
  12. BmacIL

    BmacIL Enginerd

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    They are and that's why this is so shameful for them to post. The base GT MC is the same as the GT350 MC, which has even larger calipers. BS that it's the MC. They didn't get it bled right or didn't bed in the pads. There is enough margin in the design of the MC to account for single digit percentage changes. I've also had the fact that this is BS confirmed by other highly reputable companies who specialize in track parts and cars. Anyone who knows how a hydraulic brake system operates (fluid mechanics) would be extremely skeptical.
     
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  13. mikeD4V

    mikeD4V Well-Known Member

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    PP brembos with the base GT MC and no brake issues on track (not autoX). 4 sessions per day and 20min per session. It's also on stock brake fluid :ninja:
     
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  14. Competition Orange

    Competition Orange Well-Known Member

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    hahaha, good one :thumbsup:

    I'm not saying they're straight up lying but they have to realize their progression looks absolutely ridiculous. As stated earlier, trying and hating the base brakes (probably rightfully so). Then this with the 6 pistons, all to get to their mega pricey BBK that'll without a doubt solve all of their "brake problems" once and for all? PFFT
     
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  15. qtrracer

    qtrracer Well-Known Member

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    This has been a problem for the Fox guys since they started upgrading their brakes to 4-wheel disc using all kinds of variations; from SVO/Lincoln, after market through the various sn95 solutions. Guys, it's a system. That design takes into consideration brake torque bias, which is defined by the caliper piston number and sizes, rotor size, anti-dive, weight bias, weight transfer, ABS calibration, etc. Play with one piece and you mess with the design. "Working great" is not the same as optimal. Vorshlag is looking for optimal under racing conditions.

    You'd be surprised what we've learned messing with the brakes on the Fox cars. Some of the first so-called upgrades claimed to be great improvements and were touted as such by many experts. Now we know better and in fact know those produced deficient braking even compared to the originals. Seems we are at the same early point here with the s550s. I'm not saying Vorshlag has figured it out but they are testing what they thought would work and found it didn't. Same with the various Fox brake upgrades. Only early on, we didn't have the likes of Vorshlag testing for us.

    I know from my own experience that the M/C piston and fluid displacement must match the piston sizes and numbers in the calipers. "Bigger" outside dimension does not mean larger pistons. In fact, the total displacement might be less than the 4-piston caliper (e.g., 94-98 Cobra = 2x38MM, 13" rotor; 99-04 Cobra = 2x40mm - 13" rotor; 99-04 GT = 2x44mm - 11" rotor). These re not interchangeable without other matching changes for optimal braking - not merely "great" braking. And we haven't even discussed brake torque bias and how the car behaves in dive.
     
  16. Optimum Performance

    Optimum Performance Well-Known Member
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    Could you explain what you mean by bigger outside diameter doesn't mean larger pistons?

    We have measured every caliper and piston on the S550. Going from the stock 4 piston calipers to the 6 piston Brembo caliper reduces the piston area by 4.7%. The master cylinder used with the 4 piston calipers is the same master cylinder used in the GT350. The GT350 total piston area is a 14% increase from the 4 piston calipers and a 19.4% increase from the 6 piston calipers.

    Ford has been selling both the 6 Piston and GT350 kits as bolt ons. You seem to have a good understanding of how all this works together. I understand that a larger piston surface area, due to volume will require less pressure but the original complaint was the car did not stop. That is a different issue. We also have sold many of these kits to our Track Customers who have not had any issues reported back. S550 4 Piston.jpg S550 4 Piston 2.jpg Calipers.jpg
     
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  17. BmacIL

    BmacIL Enginerd

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    Thank you! I knew that the numbers would back up what intuitively made sense.
     
  18. qtrracer

    qtrracer Well-Known Member

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    You need to measure the piston inside the sleeve. But "diameter" is not what I was talking about. The caliper itself needs to fit the rotor being used. When pistons are used on both sides the caliper dimension must increase. But the same caliper dimension can be used with a multitude of pistons sizes. So, when we are talking about brake torque, not only do you need to consider the number of pistons used and their size, but also the rotor diameter and swept area of the pad.

    For most mustangs with a weight bias of 60/40 to the front, the brake torque bias is generally 70/30. How we get that torque bias is as discussed above.

    For example on my 86 using the SVO single 76mm front caliper and 11" rotors with the TB T/C rear 44 mm caliper with 10.25" rotor I get a torque bias of about 80/20 - way too much front bias. Moving to the sn95 Cobra front 38mm dual piston with 13" rotor and keeping the rear as is, I move to a 74/66 torque bias. If I upgrade the rear to the 11.65" rotor and 38mm caliper, my torque bias is about 70/30. And if I upgrade the front to a Stoptech 4-piston caliper with 14" rotor keeping the rear the same, the torque bias is 68/32. In all the above, the only other change was from a 1-1/8" M/C to a 1' M/C. The brake pedal feel was normal, throughout but stopping distances were dramatically different.

    You have to calculate the torque bias split using something like a factory set-up as a base to gain some appreciation of what goes into the system design. Ford, like all other companies, does not upgrade brakes in isolation of other components. If we do that, the outcome will be less than optimal.
     
  19. Bahndvr

    Bahndvr Roushcharged

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    So should we try and get more braking in the back, say 60/40?
     
  20. Optimum Performance

    Optimum Performance Well-Known Member
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    With very few exceptions Mustangs (Modern ones with ABS) do not respond well to a lot of rear brake. This entire recent m/c discussion is based on no real data and the claims of changing m/c and boosters on the S550 to accommodate a swap from the stock S550 4 piston caliper to the S550 6 Piston Brembo or the GT350 calipers has been run through very complicated simulation software that looks at everything from wheelbase, tire contact patch, CG, piston sizes, m/c sizes and proven to be false. In fact the 'data' provided should have had the opposite effect. Again Ford Performance would not release a brake kit that needed a M/C and not include one. This was all related to incorrect selection of brake compounds and the installation of components.

    :repost:
     
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