GOLFMK8
GOLFMK7
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TT-RS/Golf R master cylinder

the bruce

the bruce

Go Kart Champion
Location
land
Car(s)
Golf GTI Mk.V 2008
Last edited:
M

miamirice

Ready to race!
Location
Miami
This is common in honda's. you are talking a very small move here in size so I would assume the current brake booster should be fine and you will realize a TALLER pedal.

When we put NSX brakes on a civic, the bias was thrown off requiring fine tuning the front/rear relationship. But your spec diff here is so small I think your good to go.
 
the bruce

the bruce

Go Kart Champion
Location
land
Car(s)
Golf GTI Mk.V 2008
~ 15 % !!

:biggrin::biggrin::biggrin:
 
M

miamirice

Ready to race!
Location
Miami
I am at that ratio ( for lack of a better word) right now in my civic. To be honest the pedal is too deep for heel-toe work). The car stops well, just not ideal pedal height. If you have seen my last video posts, I am struggling with heel-toe because of pedal height. I am actually going to a 2007 mini rotor that has 4 lug pattern and will fit my hub. So I can use a mini rotor and source integra type R calipers and still be with in the rules. I will however go to the integra type R brake booster and that with a possible pedal "bend" should solve it.

If your booster will mate up to the golf R MC you should have a good package. There's got to be a VW mechanic or racer on here who can chime in
 
bostonaudi

bostonaudi

Go Kart Champion
Location
Charleston, SC
Car(s)
1995 BMW M3
Most of the aftermarket BBK's work OK with stock master cylinder, and the R32 brakes do as well, why need to change it?

I have the same issue with heal and toe with new pads, pedal too high. Adjustable pedals would be nice.
 
the bruce

the bruce

Go Kart Champion
Location
land
Car(s)
Golf GTI Mk.V 2008
No doubt when fitting S3/R32 brakes on a Mk.V GTI (22,22 mm MC) you get increased pedal
travel. A bigger MC reduces wheel travel. Both is simple physics.

- 22,22 mm (Mk.V GTI)
- 23,81 mm (Mk.V R32, Mk.VI GTI, Golf R)
- 25,40 mm (RS3 + TT-RS)

That's the way it is at least in continental Europe. RHD cars at least do come with different
brake booster.
From what I read unfortunately the 25,40 mm MC does not fit smaller brake boosters.

Interesting to see VW changed from the small 22,22 mm MC on the Mk.V GTI to the same
23,81 mm MC the old R32 already had. That does mean a Mk.VI GTI is better prepared for
fitting R-brakes than the Mk.V GTI.
 
M

miamirice

Ready to race!
Location
Miami
the bruce said:
No doubt when fitting S3/R32 brakes on a Mk.V GTI (22,22 mm MC) you get increased pedal
travel. A bigger MC reduces wheel travel. Both is simple physics.

- 22,22 mm (Mk.V GTI)
- 23,81 mm (Mk.V R32, Mk.VI GTI, Golf R)
- 25,40 mm (RS3 + TT-RS)

That's the way it is at least in continental Europe. RHD cars at least do come with different
brake booster.
From what I read unfortunately the 25,40 mm MC does not fit smaller brake boosters.

Interesting to see VW changed from the small 22,22 mm MC on the Mk.V GTI to the same
23,81 mm MC the old R32 already had. That does mean a Mk.VI GTI is better prepared for
fitting R-brakes than the Mk.V GTI.
Click to expand...

So see if you can find a booster to swap in with it. I am in the same process for my civic. I bought a remanufactured 1" integra type R MC and booster.
 
cruizin01

cruizin01

Go Kart Champion
Location
C-bus Ohio
Car(s)
07 Rabbit
At least in my particular setup, I prefer the lower pedal that my 6 pistons created. Stock the car is very difficult to heal-too because the gas pedal is so low compared to the brake pedal. When at the track the low pedal and my size 13's get along just fine. I did notice though if the brakes overheat you get an uncomfortable low/long pedal travel. Hoping that's fixed with better fluid and brake ducts. Returns to normal when everything cools down regardless.

Sent from my Galaxy Nexus
 
the bruce

the bruce

Go Kart Champion
Location
land
Car(s)
Golf GTI Mk.V 2008
piston sizes of Stoptech ST-40 BBK:

It's 34 mm and 38 mm.
Click to expand...


So let's do the maths:


908 mm² + 1134 mm² = 2043 mm²

stock Ate FN3 54 caliper = 2290 mm²


So this Stoptech ST-40 seems to be a good match. :thumbsup: Keep in mind
a BBK also provides better pad pressure distribution and larger rotor size.

Cayenne brakes aren't (there are three):


34/36/38 mm : 907.920 + 1017.876 + 1134.115 = ~ 3060 mm²
32/36/38 mm : 804.248 + 1017.876 + 1134.115 = ~ 2956 mm²
30/34/38 mm : 706.858 + 907.920 + 1134.115 = ~ 2749 mm²

.... obviously Cayenne/Touareg/Q7 calipers WILL increase pedal travel (without
a much larger master cylinder) and weaken both brake force distribution and
booster/brake assist functionality. LHD Golfs/GTIs have a dual rate booster and
such significiently different pedal travel will shift its threshold.


BTW, S3/R32/R - FNRG 57 mm : 2552 mm²


Pi * radius² = area
 
bostonaudi

bostonaudi

Go Kart Champion
Location
Charleston, SC
Car(s)
1995 BMW M3
cruizin01 said:
At least in my particular setup, I prefer the lower pedal that my 6 pistons created. Stock the car is very difficult to heal-too because the gas pedal is so low compared to the brake pedal. When at the track the low pedal and my size 13's get along just fine. I did notice though if the brakes overheat you get an uncomfortable low/long pedal travel. Hoping that's fixed with better fluid and brake ducts. Returns to normal when everything cools down regardless.

Sent from my Galaxy Nexus
Click to expand...

LOl try heal and toe with 15 shoes.
 
the bruce

the bruce

Go Kart Champion
Location
land
Car(s)
Golf GTI Mk.V 2008
HYDE16 said:
Bruce can you do the math on the Forge Motorsport BBK?
-6 pistons per caliper with staggered piston sizes (30mm, 36.5mm. 38.5mm)
Click to expand...


707 + 1046 + 1164 = 2917 mm²

That's why you noticed "more bite", the mushier pedal feel and a lack of balance.

;)

This piston area difference should be the main reason for the significiently different feel.
 
cruizin01

cruizin01

Go Kart Champion
Location
C-bus Ohio
Car(s)
07 Rabbit
Im about to try out a boxster S caliper swap. It measures out to about 2275mm2. Ill report back on pedal feel compared to the 17z 6 pistons.
 
Talguy

Talguy

Go Kart Champion
Location
CT
has anyone attempted a bigger master cylinder swap yet. Just wondering if there are some out there that'll bolt directly to our boosters.
 
the bruce

the bruce

Go Kart Champion
Location
land
Car(s)
Golf GTI Mk.V 2008
From what I know the Mk.VI GTI/R32/R one (23.8 mm) should bolt on directly,
unfortunately the TT-RS/RS3 one (25.4 mm) won't (it will require the bigger booster).
 
the bruce

the bruce

Go Kart Champion
Location
land
Car(s)
Golf GTI Mk.V 2008
Found some more - Boxster S and 993/996 Turbo:



piston size/area



1. stock front caliper:


Golf/GTI - Ate FN3 54 mm caliper: 2290 mm²

S3/R32/R - FNRG 57 mm: 2552 mm²



2. aftermarket - proper match:


AP Racing 6-pot CP7068-00 (355x32 ) > 2350 mm²

Boxster: 40 mm + 36 mm > 1257 mm² + 1018 mm² = 2275 mm²

Boxster S: 40 mm + 36 mm > 1257 mm² + 1018 mm² = 2275 mm²

993 Turbo: 36 + 44 mm > 1018 mm² + + 1520 mm² = 2538 mm² (on the edge)

Brembo GT Satteltyp A: 40 mm + 36 mm > 1257 mm² + 1018 mm² = 2275 mm²

Stoptech ST-40: 38 mm + 34 mm > 908 mm² + 1134 mm² = 2043 mm²



3. aftermarket - poor match:


Forge: 707 mm² + 1046 mm² + 1164 mm² = 2917 mm²

996 Turbo: 40 + 44 mm > 1257 mm² + 1520 mm² = 2777 mm²

Q7/Touareg/Cayenne (three variants):

34/36/38 mm : 907.920 + 1017.876 + 1134.115 = ~ 3060 mm²
32/36/38 mm : 804.248 + 1017.876 + 1134.115 = ~ 2956 mm²
30/34/38 mm : 706.858 + 907.920 + 1134.115 = ~ 2749 mm²



4. master cylinder diameter:

- 22,22 mm > 388 mm² (some Mk.V GTI, Mk.V + Mk.VI Golf)
- 23,81 mm > 445 mm² (Mk.V R32, Mk.V GTI, Mk.VI GTI, Golf R)
- 25,40 mm > 507 mm² (RS3 + TT-RS)



If you know the piston diameter: Pi * radius² = area


edit - AP kit added
 
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