Background:
I'm building my 914 into a 6 GT right now and a full suspension set up. The car is still gonna be driven on the street but is going to see a lot of track time especially with POC.

Discussion:
What are the arguments between S-Caliper/Alfa Brembo and M-Caliper in the rear VS Boxster brakes all the way around with Carrera Rotors.
19mm Master on the S-Caliper and 23mm on the Boxster set up.

Firstly I understand that the 'Boxster' set up is heavier but is the increased stopping power worth the added weight?

What are your experiences with the Boxster set up?

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First, are you talking front or rear?
There are no Alfa or S calipers for the rear, only 914-6, M or Boxster calipers.

If you want it to look like a GT, use 914-6 or M calipers on the back.
The Boxster calipers are lighter than the steel calipers but the Carrera rotor might even things out. Only the 914-6 caliper has a parking brake unless you use 911 e-brakes.

Same on the front. M calipers were on the six, S calipers on the GT. Use the M or Alfa calipers if you are staying with 3” struts. S & Boxster calipers require 3.5” struts and Boxster calipers also need adaptors.

Eric Shea’s threads are still some of the best on the web.


http://www.914world.com/bbs2/index.php?showtopic=105728

http://www.914world.com/bbs2/index.php?showtopic=91963

http://www.914world.com/bbs2/index.php?showtopic=4909

Hi Mark,

Thank you for the Information.
Maybe I should have been more specific:
So First of the car is getting the 911 parking brake. No discussion!
Second I understand the difference between struts 3" vs 3.5"
I also understand, that there are no S or Alfa Calipers for the rear. in my case in that combination I would use M Calipers in the rear. If I where to use Boxster Calipers front AND rear I would use Stomski adapters.

The point is more like, is it worth going the extra step from S-Caliper or Alfa Caliper in the front and a M-Caliper in the rear to Boxster Calpers ALL the way around.

What are the experiences, is there a noticeable difference, especially on track. Second are there (big) draw backs with the Boxster set up I should be aware of. AKA wondering why not more people use it!

Has anybody used the Boxster Calipers with 15" Cookie Cutters?

We put Boxster brakes on a lot of our project cars that get used hard and don’t need originality. Most are 911’s with 3.6 engines. Stompski makes 914 adaptors for the front but not the rear. At least that’s what Stephen told me last year. I believe Rebel racing and rich Johnson have rear adapters. We use a 23 MC but most of our cars get a 911 brake booster. It’s not absolutely necessary but makes the pedal easier in traffic on a road car. Boxster calipers will work with 15” Fuchs and cookies.

Sorry, I can’t speak to what might be best on the track other than the Boxster pads should last longer than the other choices and give you better heat controls with the bigger rotors.

what about 944 Turbo Brembos, they look better than Boxsters,,more vintage, or even 930 ??


found this; QUOTE(ClayPerrine @ Oct 3 2006, 07:43 PM)

I have 944 turbo calipers all the way around.

The fronts have to be redrilled to fit the 3.5" bolt spacing. The rears had to have a custom mount fabricated.

No, the 15" wheels will not fit over the calipers. The 16" wheels are a tight fit.

Note others say 15s will fit,,??

I had 944 turbo brakes on the front and you have to oblong the holes to work with 3.5” struts. I then bought a set of Boxster brakes front and rear using Rich Johnson’s Kit. I’m using a T in the rear instead of the proportioning valve. I am also using a 19mm master cylinder. Braking is awesome and well balanced. I have only autocrossed the car and am quite happy with the setup. I also have a 911 parking brake. I have slammed on the brakes on corners and on straights and the front always locks up first. I started off with 16” 993 rims and now 17” fixse. I have not tried 15”

my Brembo's are mounted the same way,someone did it for the PO very neat job,no adaptors needed which is good because they aren't legal in my country besides,I was unsure how they would work before driving the car ,shouldn't have worried as the car stops very well for little pedal effort...the system just works on the 914.
The handbrake system is good in practice but not correctly done as who ever fitted them didn't weld back plate retainers to the trailing arms as per the 911 system,I will be sorting that.
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I am currently running the Alfa Romeo Brembos on the front and 914/6 vented on the rear. I do several track events a year in hot weather. They work fantastic! Not too much wear and I am running hawk brake pads. My car has a built 3.0L. The funny thing is I used to have stock Carrera calipers and rotors (yes different struts with 3.5" spacing) so I down sized and saved about 20lbs! The steel Carrera rotors are thicker and heavier. The steel calipers are boat anchors. My car stops very well. I run pretty good lap times. PMB sells the Brembos new and it sounds like the m calipers for the rear are the way to go since your doing the 911 set up. Get frozen rotors for your front.

Boxster front and rear on my car. 23mm M/C. Works great for track and street. No parking brake, though.

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So one consideration is weight. 3.5" struts weigh more than 3" ones. I don't have the numbers but I've held enough of them to know there is a difference. Bigger calipers get bigger rotors. So if you want the lightest "big brake" option, it's 3" Alfa Brembos. If weight isn't a concern over the biggest brakes, it's the Boxsters, front and back. If you really want BIG brakes, it's 911 turbo caliper$$$.

The Brembos work good for me

Set of 4 Boxster calipers for sale - $400 - Correct early ones.

https://forums.pelicanparts.com/porsche-911...clears-15s.html

Definitely, the cheapest and easiest...

I'm another one running the alfa brembos on the front 914/6 struts and PMB 914/4 V-caliper with vented rears. Using a stock 17mm master cylinder, 108mm hubs and stubs, G50 CV's and SAW axles.

ya its like having power brakes..but on the track the pedal gets longer and longer...for the street its nice, but the travel is longer...BTDT

The Boxster calipers are significantly lighter than any of your other choices so even with the adapters you wont be any heavier with that setup.

Rich Johnson adapters that is. I have a thread somewhere with pictures. I modified the adapters to run vented rotors front and rear.

Here you go Andy...

http://www.914world.com/bbs2/index.php?showtopic=170890

Sorry if I missed this or am just being dense, but is there no way to mount the Alfa or Boxster brakes without first swapping to a 911 strut?

No

Good morning and thanks Mark.

So I convert over to 911 struts, and at that point you might as well go for it and so it begins...grin.

but if you find a deal on 3 inch bolt hole spacing 911 struts, all good , go with the alfa calis. same size as S/A calipers