# Porsche Boxster front calipers upgrade for MK4 GTI



## christianrojas (Feb 23, 2009)

Hi I wantad to know if the BRACKETS for the front calipers of the Porsche Boxster (986.351.421 & 422) are the same as for the rear of the Porsche Boxster S (996.352.421 & 422) calipers to be fitted in a 2001 Mk4 Golf GTI. I bought the 034 Motosport brackets and have 312mm rotors. I would be buying one or another mostly because of the brackets but also because the Boxster S rear calipers are red and the Boxster front are dull black. I also think that the rear calipers would have a better use for the street because of its smaller pistons.
I know that the rear calipers of the Boxster S are used in VAG cars but really need to know if the brackets to use would be the same as the Boxster front calipers.
I leave you and interesting quote from Briskoda.net
_ "Copied from UKiv's,carriers can be purchased from DaveB1970 as he is the brake expert.There is a another choice but it depends on budget.
2.5 and 2.7 (986) Boxster calipers are dimensionally the same front and rear, they also share this caliper with the 996 Carrera rear. Boxster Calipers on 2.5's and 2.7's are a matt black anodised finish
The 986S (Boxster S) has the same setup as a 996 Carrera 2/4 Boxster S calipers are Red,..... 996 Calipers are Painted Gloss Black or Silver as an option.
Buyer beware boxster rears 986.352.421 & 422 are configured for a 20mm disc and you cannot physically get this caliper over the top of a 25mm wide VAG 312 Disc. The difference is on the pad pegs, they extend further out onthe rears to fit the thinner discs
In summary
Boxster (2.5 & 2.7) Fronts - All Good (Need reversing though) 986.351.421 & 422 goes on 312 or 325mm discs
Boxster (2.5 & 2.7) Rears - No Good for VAG 996.352.421 & 422 *************BEWARE THIS IS THE SAME PART NUMBER AS 996 REARS THAT DO FIT **********************************
Boxster S & Carrera 2/4 Fronts (and also 996 Twin Turbo rears) - Good for VAG on custom 330mm discs - search Rays (aRd)'s posts 996.351.425 & 426, loverly compact setup goes under 17's
Boxster S rears - Good for VAG dont need reversing and come red as standard 996.352.421 & 422 goes on 312 or 325mm discs goes under 17's
996 Carrera 2/4 Rears - Good for VAG dont need reversing 996.352.421 & 422 goes on 312 or 325mm discs goes under 17's
Cayenne 6 pots - goes onto a R32 disc there are multiple versions of this caliper, ideally unless you want to willy wave there is NO POINT in getting cayenne turbo caliepers the pistons are huge and you will have pedal travel equal only to your clutch!!! best bet is get the silver ones from the "normal" cayenne and refurb them red. Also VW touareg calipers and Q7 Calipers are the same but with smaller more suitable pistons. goes under 18's
996 Twin Turbo AKA "The Big Red" 996.351.429 & 430 fit beautifully onto a Mk4 R32 disc with a 10mm spacer, need reversing though no big problem use bigger 142mm mounting centres as they're HUGE - well suited to a mk4 maybe a FI R32 so thats its just caliper and carriers and lines. Really nice calipers these one of my favourites goes under 18's
996 GT3 RS 6 Pots sometimes in Red when used on a GT3 but also used in Yellow in the PCCB arrangement, PCCB calipers can be mounted straight onto steel rotors with a pad change, beware if the ceramic piston caps are missing they are not available individually even though most ssellers on ebay will swear they are - its a new caliper and they are £4K. Very capable caliper with very small pistons easily reversed and very light dimensionally a 6 pot version of the "BIG RED" when found in red they are sometimes sold as "BIGGER REDS"
Aston, Ferrari & XK8 calipers can also be used.
All the above can go onto a Mk5 either the Mk5 GTi 312, Custom 330mm disc above or a custom 350mmx32mm disc for the 996TT Fronts, Cayennes, Aston Martin stuff. B7 RS4 calipers are bolt on Mk5 with spacers
The calipers that DO need reversing have larger pistons, some see these bigger pistons as a benefit for ultimate stopping power with racing pads on a track. For fast street the smaller pistoned calipers CAN all give forehead against windscreen performance with an absolute solid pedal because smaller pistons need less pedal travel which is Hydraulics 101!"_
Will be waiting for some guru answer.
Thanks a million!
Chris.


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## Blackwheel'n (Jun 11, 2007)

*Re: Porsche Boxster front calipers upgrade for MK4 GTI (christianrojas)*

Niiice. Had fun reading that. http://****************.com/smile/emthup.gif


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## TeemuM (Feb 10, 2006)

*Re: Porsche Boxster front calipers upgrade for MK4 GTI (christianrojas)*


_Quote, originally posted by *christianrojas* »_HiBoxster S & Carrera 2/4 Fronts (and also 996 Twin Turbo rears) - Good for VAG on custom 330mm discs - search Rays (aRd)'s posts 996.351.425 & 426, loverly compact setup goes under 17's

I have 996 C2 calipers with 312mm disks and those are perfect fit. Boxster (non-S) pads don´t use whole friction surface of that 312mm disc.
Here are 312mm disks with those 996 carrera front calipers.








I have also have had those R32 disks with 996TT calipers. That caliper pad doesnt also use whole friction surface of that disc.


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## christianrojas (Feb 23, 2009)

*Re: Porsche Boxster front calipers upgrade for MK4 GTI (TeemuM)*

Hi TeemuM, thanks for the reply, but still you haven't answered my question on wether I can use the same brackets for the 986 front calipers as for the 996 rear calipers. 
Will be waiting your reply.
Thanks!


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## fuzion (Nov 25, 2005)

so what about the rear? what options are there without large modifications to make it work?


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## hippierob (Apr 21, 2006)

*Re: (fuzion)*

http://****************.com/smile/emthup.gif . . . . nice bit of info? muchas gracias amigo....


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## DenmarkGti (Oct 11, 2009)

Hey great tread ! I want to fit the Vw touareg 4 piston brakes on my golf mkiv, an here is the question. Do there exist any spacers for these calibers to fit on the mkiv or ?


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## RaceCarGuy (Jul 17, 2009)

*Re: Porsche Boxster front calipers upgrade for MK4 GTI (christianrojas)*

Hola Chris
Great post! Do you know if the rear calipers from the Boxster S plus the bracket from http://www.purems.com/products/product.php/II=1310 will work with 312mm TT rotors on my MK3 VR6 running 16" OZ Superlegeras.
Thanks
Ja


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## HotredVR (May 13, 2002)

did this ever get answered........


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## 35i 2000 (Jan 27, 2005)

this is great info, should have this moved to FAQ's


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## joseluis.17g (Aug 8, 2011)

RaceCarGuy said:


> Hola Chris
> Great post! Do you know if the rear calipers from the Boxster S plus the bracket from http://www.purems.com/products/product.php/II=1310 will work with 312mm TT rotors on my MK3 VR6 running 16" OZ Superlegeras.
> Thanks
> Ja


Bump
I would also like to know if the clear 16" ultraleggera


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## Guyver96 (Jan 17, 2007)

damn this still hasn't been answered? I just got a sweet deal on some s calipers and id like to know was well all my searches show the 986 calipers or nothing related to what id like to know... so bump till this gets an answer please...


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## Guyver96 (Jan 17, 2007)

The brackets I ordered from usrt bolt up to the boxster red rears.... As to whether rear boxster calipers work or not I've done and uses the calculator several times and it is a 15% increase in brake power.. I've also had several techs that work one Porsche and drive VWs help me out with this and they also confirm it works and is an increase but to also keep in mind there is more brake effort since there is more space to fill due to the increase in pots/sizes.... I work with Porsche techs almost daily so ill trust them over anything anyone on this forum says... If someone has issues with this set up its likely to be the change in peddle feel , system not bled properly or somethin similar... Also they also mention that by switching from a floating caliper to a fixed mounted caliper it improves brake performance.

http://i36.photobucket.com/albums/e41/Guyver96/temporary-30.jpg
I can post many many more pictures if you guys are interested too... I do many gt3,cup cars graphics, paint protection film..


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## cocadave (Mar 21, 2015)

Unfortunately the rears Calipers will NOT work, one of them physically fits the disc diameter but it remains that the size of the Pistons are simply too small, the calculations if input correctly will show that with the boxster rears with 28/30mm Pistons reduces pressure to the Calipers by around 43%...

there is a thread on this forum that goes into various incorrect statements that they do work but they are all wrong, even companies are manufacturing and supplying adaptors for a setup that is actually downgrading from standard OEM setups.


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## Guyver96 (Jan 17, 2007)

That's interesting cause all the shops I do work for all guarantee it'll work, confirmed that the master cylinders are even the same between mk4 golfs/beetle/jettas and porsche boxsters including the s model. Not to mention that I've also don several searches for the 996352422/421 caliper and all I find is it doesn't work but nothing from someone who actually has tried them.... The one thread I did find wasn't even the same caliper I mentioned and is only complaining about foot travel.. Common sense would say with bigger pistons its obvious there is more space to fill there for more peddle travel... Even the brake piston area calculator confirms its a 7.1-7.5 increase in piston area per side... I don't know what math some have done but our cars have 1 (one) single piston per axle! The calculator explains to multiply by 2 for floating calipers the sum of the equation . So the math I've seen in a few posts showing the brake calculator with the 54/7 mm piston of our cars is wrong... 

On a plus note I've got them on my car and they are fine minus the little more peddle travel mushy peddle which I'm sure will get better with stoptech brake lines .. my abs also kicked in when I attempted a hard stop from 50-60 on a bumpy road, actually scared me more then the actual brakes locking up...


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## Ephry73 (Feb 18, 2002)

Was this ever tested?


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## Guyver96 (Jan 17, 2007)

I've had them on my car a few months , I had to had a shim yo clear my rotors between caliper and bracket the rubbed his enough to annoy me and the peddle feels sponge but I also have stock brakes lines which expand and also haven't bleed my system completely plus i have a leaky master cylinder... So yes they work for me.. Again these are the red rear calipers off an S! Not the standard rear calipers..
My abs also still works, found a lovely bumpy street i can safely hit 40-60 slamed on the brakes n it kicked in..


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## PORSCHE TECH RPM (Sep 22, 2015)

Porsche uses several different pedal ratio boosters from car to car depending on caliper configuration, we have swapped many boosters around on track cars to promote better pedal feel on these cars. not sure of the % numbers for pedal effort but im sure you could find out. Also remember when adding larger piston calipers the master should be changed accordingly to add more pressure and fluid volume... just my 2 cents


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