# POSCHE BOXTER S CALIPER on MK6 GTI Help needed!!!



## BySeaByLand (Aug 30, 2010)

So long story short, i have a set of boxster S calipers. I paid a reasonable amount for them thinking that it wouldn't be that hard to get them to work. Now im not sure what the hell i need to get them to work. I've been reading around a ton but finding some conflicting information. I have all of the equipment i was told i would need, but there are some inconsistencies im finding. For one, the caliper to carrier bolts i have or don't have don't fit the caliper or bracket. Could someone back me up here or point me to where i need to go to find a proper DIY on these brakes? they aren't much different than the non-s. I just want to get them on the car and be done with it, im already over my budget on these, but I cant bring myself to sell them off after i've already put work into re-finishing them.:banghead:


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## mk3trekk (Mar 11, 2005)

I'm no expert, but i think Apikol is the only one to sell the caliper carrier you'll need.

Double and triple check that this is the right part you'll need, I may have linked the wrong part.

http://www.apikol.com/index.php/a3-vw-mkv-mkvi-boxster-brake-brackets.html


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## petethepug (May 25, 2001)

You're almost home man ... He's right

*http://forums.vwvortex.com/showthre...oxter-brake-upgrade-parts-list-amp-future-DIY*

I used the Apikol adapters on my Allroad rears. Used the Apikol adapters to go from 255x10 (B5 2.7t) to the gorilla 300x22 (B6 S4) discs and calipers from th V8 Allroad (B5 4.2). 
*Order early because if they're out it takes 4-6 weeks to tool and plate.*
*
http://www.apikol.com/index.php/a3-vw-mkv-mkvi-boxster-brake-brackets.html*


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## BySeaByLand (Aug 30, 2010)

The calipers I have are for the 996/boxster s and may be the rear calipers. Part number is 996.352.422. I thought I found someone who made these work on a mk 6 for front fitment. 

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## BySeaByLand (Aug 30, 2010)

The above thread is for the non s calipers. 

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## petethepug (May 25, 2001)

Might be these



petethepug said:


> This? 94.99 quid for Mk III Spindles w/ a 312x25mm with Porsche *Rear* calipers from 911/996/BOXTER (Part #'s 996.352.421 and 996.352.422)
> http://www.creationsmotorsport.com/product-detail.php?pid=131


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## BySeaByLand (Aug 30, 2010)

I called apikol. Was told the pistons aren't big enough for front fitment use and that they are only good enough for rear. I'm in the process of trying to recoup some lost money since I've fully refinished these and are completely ready to go on the car. Sigh. 

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## petethepug (May 25, 2001)

*You've got the right Porsche calipers (Carrera 2/4 rears)

 IF 

they're wide enough to fit over your 25mm brake rotor. The next step is to find the adapters others have used. 

The pic & add I copied in the previous post from Creations Motorsport shows Porsche calipers (996.352.421 & 422 ) will work. HOWEVER, I don't think they're aware that Porsche used the same part number on calipers for the 20mm wide discs as well as the 25mm wide disc calipers *



BySeaByLand said:


> The calipers I have are for the 996/boxster s and may be the rear calipers. Part number is *996.352.422*. I thought I found someone who made these work on a mk 6 for front fitment.
> 
> Sent from my SPH-L710 using Tapatalk
> 
> ...


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## Chickenman35 (Jul 28, 2006)

BySeaByLand said:


> I called apikol. Was told the pistons aren't big enough for front fitment use and that they are only good enough for rear. I'm in the process of trying to recoup some lost money since I've fully refinished these and are completely ready to go on the car. Sigh.
> 
> Sent from my SPH-L710 using Tapatalk


Apikol is correct. The Porsche rear brakes with 28mm/30mm pistons have an effective piston volume of 42.2% LESS than the single piston 54mm FLOATING calipers. This will cause dramatic DECREASE in brake rotor " Clamping Force" * People do not seem to understand the difference in mechanical/hydraulic advantage of floating calipers over fixed mount calipers.* :banghead: 

Member " Petethepug " has made a basic mathematical miscalculation and is providing incorrect information to members in suggesting that rear calipers with the small 28mm/30mm pistons are correct. Sorry, but with respect, he is just simply wrong and he should retract his information. I know he's trying to help...but he's made a big " Ooops ". I've done the same thing many a time...but not in this case. :beer:

I've explained why in another thread that can be seen at the following link:

http://forums.vwvortex.com/showthread.php?7003812-Porsche-caliper-issue&p=85938635&viewfull=1#post85938635

Make sure that you read the linked calculation site and understand it.

http://brakepower.com/help_abc_27_PAC_t.htm

Then research further. The equations are mathematical facts. WilWood, Brembo, Alcon etc all use the same method of calculation. If you don't care to believe me, Apikol or all of the other online calculators, phone up WilWood's Tech line and ask them ( 1 805 388-1188 ). All of the dimensions are provided in the links I gave. Give them the comparison values and they'll tell you the exact same thing. The Porsche 4 piston *rear calipers*, with 28mm/30 mm pistons, have an effective piston volume of 42.2% LESS than the OEM 54mm single piston FLOATING caliper ( of a TT MK1 or Audi A4 B5 ).

BTW, WilWood simplifies the comparison between Floating Calipers and Fixed Mount calipers by calculating the piston area of only ONE SIDE of a caliper. This effectively negates the difference between in design of floating calipers and fixed mount calipers. It's in their FAQ. It makes things easier to understand and is less confusing to the average layman.

This caliper design difference ( floating vs fixed mount ) and it's effect on clamping force is also clearly explained in " The Brake Handbook " by Fred Puhn. Get it, Read it. Understand it.

http://www.amazon.ca/Brake-Handbook-Fred-Puhn/dp/0895862328 

Written in the hopes to clarify the confusion out there... which seems to be running rampant :facepalm: :beer:


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## BySeaByLand (Aug 30, 2010)

I'm looking to run these on the rear now and will be finding a new set of non s to run for the front. I was going to increase the rotors on the rear to oe front rotors. Will the s brackets that apikol sells fit the bill to mount them? 

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## BySeaByLand (Aug 30, 2010)

So yeah, how about running these on the rears again? Should I need anything other than getting front rotors and the apikol brackets to make these work? I'm concerned about the e brake mostly...but should I be concerned about more?

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## ridgemanron (Sep 27, 2011)

BySeaByLand said:


> I'm looking to run these on the rear now and will be finding a new set of non s to run for the front. I was going to increase the rotors on the rear to oe front rotors. Will the s brackets that apikol sells fit the bill to mount them?
> 
> Sent from my SPH-L710 using Tapatalk


My 2012 Turbo Beetle shares the same front/rear brake set-ups as GTI's and GLI's. For the 'fronts' I
went with the SPM (Steve Perry Motorsport) 345mm rotor kit that allows using the existing OEM caliper
set-up in the car. For $545 (www.drivespm.com) you need to order their M5/6 Brake Upgrade Kit that
comes with their custom adaptors as well as a set of steel braided brake hoses.

For the 'rears' I found that WP ProBrakes also has a kit that allows using the existing rear caliper set-up
while adding their large 322mm rotors. Their kit is $900 and is also listed as being for MK5/6 cars. 
Note: WP is presently refining the adaptors, so that they will allow custom fitting for the OEM rear set-up
in the 2012-14 Turbo Beetles, as well as the late model GLI's and GTI's. Originally, their adaptors were
made for the previous series of MK6 cars and this required some modification of them by me. They are
on the car now and the fit is no problem after modification but the 'soon to be released' refined adaptors
are being tested as we speak and should be available shortly.

With 345mm fronts and 322mm rears, the look is much more substantial than the OEM 312mm fronts & 286mm
rears. Used my existing OEM brake pads, since they had very little wear, and have experienced no braking
problems. Note: WP will reduce the cost to $800 with a group buy of 10 sets.


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## petethepug (May 25, 2001)

Hey Richard (Chickenman35),

Nice read you posted as well as links to the sites that allowed me to wrap my head around hydraulic theory. 









This has been x posted to the other recent Porsche caliper posts to clarify that PORSCHE BOXSTER REAR CALIPERS WONT CUT IT AS FRONT CALIPERS ON 99% OF THE CARS OUT THERE. 

*This fact along with Porsche uses identical part #'s for the smaller rear Boxster calipers (with thinner discs) as well as the calipers on the Porsche 996 C2/C4 rears with (thicker discs). Niether of these options will work because their pistons are too small at 28 & 30mm.* The only exception seen for using Porsche rear calipers is the 993 C2/C4 rears that run 34 & 30mm (1.34 & 1.18") pistons, BUT AT 10.02in[SUP]2[/SUP] they're still sized too small.

So the rule with using Porsche calipers on your ride is .... Don't use *rear *Porsche calipers on the front of your ride.



I'm only about 75% there on grasping the basics but the rest will come with time and application. I had a nice flashback to instructors teaching thermal dynamics from my apprentice days. I'll memorialize the rest, mostly for myself, since I wont remember most of this because I have so many irons in the fire right now.

Porsche uses FIXED calipers, mounted as RADIAL except earlier versions.

(below) Early *AXIAL *mounted *FIXED *calipers from the Porsche 944.










(below) Later *RADIAL *mounted *FIXED *calipers from the Porsche 996. You can see these need adapter brackets to mount on our VW/Audi cars.









So, moving on to Piston area of our calipers. Thank god for the piston area calculators at BrakePower.com. I put some screen shots in since it's easier to show how to plug the numbers in than explain it.
http://brakepower.com/help_abc_27_PAC_t.htm

VW uses *FLOATING *calipers, mounted as *AXIAL*

Mk I tt 54mm front Girling Axial floating caliper. 
As Richard stated, with floating calipers the final number is doubled. 







The OE Mk I TT Girling 54 front caliper has *14.18"* on the piston are NOT the 7.09" shown on the calculator.



Porsche Boxster *front *FIXED, RADIAL calipers
4 pot piston
2 @ 36mm or 1.417”
2 @ 40mm or 1.574”












Porsche Boxster *rear *FIXED, RADIAL calipers
4 pots per caliper
2 @ 28mm or 1.102”
2 @ 30mm or 1.181”


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## BySeaByLand (Aug 30, 2010)

Still not answering the question at hand. What is needed to mount them on the rears as they should be. We've moved on with the piston volume and clamping pressure being insufficient from the front. 

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## petethepug (May 25, 2001)

Had to clear up the confusion I caused on Porsche caliper compatibility for VW's before getting to what you're asking for.

You've got two options: 


Research and find someone who has already made brackets or willing to make rear brackets to mount the Boxster rear calipers along with a stand alone parking brake. 
Use the HPA BBK kit for the rear that integrates a Porsche style rear drum brake into the rear rotors. 

Door number one:
Find a kit similar to this ...a http://forums.vwvortex.com/showthread.php?6012488-FS-Cayenne-330mm-rear-BBK-(brackets-only) or this... b http://www.golfmkv.com/forums/showthread.php?t=114114 

*a*

















*b*









Door number two:
http://www.hpamotorsports.com/product_bbk.html









You're going to be sending quite a few emails to folks who have already accomplished the engineering on the set up and waiting to be paid for their work. Finding those individuals is the hardest part.


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## BySeaByLand (Aug 30, 2010)

I agree. The only thing I've been finding has been the cayenne rears using a viper e brake. Plus I'm not a member on most of the forums that they've been on. I'm just hoping the cost of the bracket isn't outrageous. 

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