4 Pot front brake Callipers for 3.2 Carrera

[strosek34]

I've got 968 4 pot calipers on mine with 3.2 discs,  slightly elongated the holes to fit,  968 and 964 calipers are similar/if not the same,    but 968's are fitted on the trailing edge and 964 on the leading edge,  so bleed nipples and crossover pipes need flipping over to get the nipples at the top.  (Best place for them in my view )

Calipers are very light,  probably similar to Boxster's.

I've had them on for about 10 years or so with no issues,  that includes a few track days.  DS2500 pads all round.  

[hagarep]

944 turbo (same calliper, different piston sizes I think) with custom mounts and floating 930 rotors.

Some people also use 944 turbo discs, although I think they need to be spaced out a little.

[Ant7]

18 hours ago, strosek34 said:

I've got 968 4 pot calipers on mine with 3.2 discs,  slightly elongated the holes to fit,  968 and 964 calipers are similar/if not the same,    but 968's are fitted on the trailing edge and 964 on the leading edge,  so bleed nipples and crossover pipes need flipping over to get the nipples at the top.  (Best place for them in my view )

Calipers are very light,  probably similar to Boxster's.

I've had them on for about 10 years or so with no issues,  that includes a few track days.  DS2500 pads all round.  

Hi Steve,

Thanks for the info on both the 968 and 964 Callipers, can you confirm which callipers fit in the same position as the original 3.2 callipers without having to flip the pipes etc.

Ant.

[hagarep]

Just a note of warning!

These callipers are designed for a 28mm wide disc, but can if accommodate a 32mm 930 rotor between the pads.

3.2 Carrera discs are 24mm wide, so do not let the pads wear down too far or they may escape their location and jam between the calliper body and disc. The pistons would definitely come out too far for comfort.

Edited June 21, 2023 by hagarep

[Chris T]

But early Boxter callipers are designed for a 24mm disc...... Honestly, they are cheaply available, fit standard 3.2 rotors (which are also easily fitted to an SC) and work great. Why over-think it? 

My 2p of course. 

[Beaky]

A bit pricy but saves all the adaptions, why and has good support, why not go Carbon 12's.

6 pots up front, 4 pot rears, no brake bias adjustment required  

[Chris T]

4 hours ago, Beaky said:

no brake bias adjustment required  

Only adjustment is to remove the bias valve, 2 minute job and not even there on an SC..... You will have to bleed the brakes no matter what. 

[DavidH]

I'm fitting 986 front callipers at the minute and struggled to find a banjo to fit the new hard line at the calliper end.... (female M10 straight)

You can get away without them but it saves the brake line being over exposed to any debris.

In case it helps, I tracked them down at https://www.hispecmotorsport.co.uk/ 

Bit spendy but £34 for banjos, bolts, washers & delivery 

Adapters: https://www.design911shop.com/p/stomski-racing-sr046-front-brake-caliper-adapter-for-porsche-911-84-89-with-996-boxster-calliper/?currency=GBP&country=GB&gclid=Cj0KCQjw4s-kBhDqARIsAN-ipH0jE8YpjBM5EnheNuHl6WqPXgzZc9pc5jCKlnX3QoBF3cV4BqgpfUwaArRkEALw_wcB

Edited June 22, 2023 by DavidH

[strosek34]

On 21/06/2023 at 15:22, Ant7 said:

Hi Steve,

Thanks for the info on both the 968 and 964 Callipers, can you confirm which callipers fit in the same position as the original 3.2 callipers without having to flip the pipes etc.

Ant.

I am wondering whether I am getting 

 

On 21/06/2023 at 15:22, Ant7 said:

Hi Steve,

Thanks for the info on both the 968 and 964 Callipers, can you confirm which callipers fit in the same position as the original 3.2 callipers without having to flip the pipes etc.

Ant.

 

Just now, strosek34 said:

I am wondering whether I am getting confused between 964 and 944 turbo,  either way 964/944 ones have the pipes/nipples the right way up for 3.2,  but it's very easy to swap the 968 pipes/nipples to the way you would need them,  spanner job.

 

Sorry, mis typing stuff,  

[Ant7]

On 23/06/2023 at 21:51, strosek34 said:

I am wondering whether I am getting 

 

 

Sorry, mis typing stuff,  

Cheers Steve! 😎

[Northy]

I’ve got the calipers and adapters now, so what’s the verdict on the master cylinder? For the sake of £150 just put the turbo one on? 
 

It’s this one, right?

[sopor]

No, I think that would be a mistake. Check the diameters of the pistons and compare the sum of their surface areas to the original callipers.

According to https://www.pelicanparts.com/MotorCity/wmv/brakes.htm 964 front callipers have every so slightly less piston surface area than 911 SC/3.2 callipers. So no need to change MC. I believe Boxster callipers have the same piston sizes as 964 callipers.

[axel]

adapter set complete with brakes 3700 dollars lol. elephant racing knows how to charge

[SilverWT]

9 hours ago, sopor said:

. I believe Boxster callipers have the same piston sizes as 964 callipers.

If that is the case a turbo mc is needed. Regardless of theory, in practice the pedal travel increases too much with Boxster calipers. The turbo mc reduces the pedal travel to a good place.

Mark

[sopor]

The larger bore MC will displace more fluid; if the the rear calipers are unchanged won’t that increase rear brake bias?

My IB has Boxster calipers and my 914/6 has 964 calipers, both with the standard MC.

[SilverWT]

22 minutes ago, sopor said:

The larger bore MC will displace more fluid; if the the rear calipers are unchanged won’t that increase rear brake bias

Not in my experience/understanding. All physical parameters remain the same at the rear, just less foot pedal travel to get to the same point.

[Nige]

Main thing I found with Boxster callipers is that they lock up less/easier to modulate.

Can't recall any extra pedal travel differences.

[Chris T]

I agree with Nige. Much less prone to lock ups and with good braided lines, decent fluid and a good bleeding I didn't notice any longer pedal travel (although obviously travel IS longer) than before. 

[Nige]

Also add, I swapped out the callipers from a fully refurbished system which included new flexi lines and restored original callipers.

[LukasM]

2 hours ago, sopor said:

The larger bore MC will displace more fluid; if the the rear calipers are unchanged won’t that increase rear brake bias?

My IB has Boxster calipers and my 914/6 has 964 calipers, both with the standard MC.

 

+1 on what SilverWT said, the MC size only changes the ratio of effort to travel. The bias is a matter of piston number + size front vs. back, and if there are any other fluid redirections in the system, such as a brake proportioning or adjustable bias valve.

[sopor]

Y

54 minutes ago, LukasM said:

 

+1 on what SilverWT said, the MC size only changes the ratio of effort to travel. The bias is a matter of piston number + size front vs. back, and if there are any other fluid redirections in the system, such as a brake proportioning or adjustable bias valve.

Agreed - not sure what I was thinking, if at all! 😀

Looking on Pelican some people have changed the MC and some haven't. Consensus seems to be that the turbo MC requires less pedal travel but has a higher effort. Less pedal travel is perceived as a firmer pedal by some. Given that the only extra effort in swapping the MC out at a later date is a bleeding the brakes a second time you can always try the standard MC and see how you get on.

[SilverWT]

Thinking about this a bit more, the increased pedal travel was not a big issue on the road and I left the original mc on for some time.

It was an issue on the track where you brake much harder and use more of the pedal travel. It was both a bit disconcerting and also more difficult to modulate braking with a foot too far down.

Mark

[hagarep]

1 hour ago, LukasM said:

 

+1 on what SilverWT said, the MC size only changes the ratio of effort to travel. The bias is a matter of piston number + size front vs. back, and if there are any other fluid redirections in the system, such as a brake proportioning or adjustable bias valve.

The MC changes the volume of fluid moved and should be proportional to the volume of your combined callipers. Less pedal travel is a side effect. If you run 4 pot callipers all round, then you have to move more fluid. I went from a 19 to 23mm non-servo MC. If you only change the front callipers then I guess it's personal choice/feel, but as Mark suggests, if you have long travel when everything is perfect, imagine having brake fade or a bit of air in the system and you have no safety margin.

[sopor]

18 minutes ago, hagarep said:

 If you run 4 pot callipers all round, then you have to move more fluid.

That’s a function of total piston surface area, not just the number of pistons. SC/3.2 calipers have 2 48mm pistons. 964/Boxster have a pair of 40mm pistons and a pair of 36mm pistons. The surface area of the SC/3.2 pistons is slightly bigger than those of the 964/Boxster calipers so the SC/3.2 calipers will require slightly more MC movement to achieve the same amount of pad movement.

That’s the theory…

A fresh MC may simply feel stiffer as the seals should be working at 100%; an old MC perhaps less so.

[Phill]

I had SC MC with Boxster fronts and standard rear. Feel was absolutely fine. Pedal may have been a smidge longer but nothing to be remotely concerned about.