GermanLook Forums  

Go Back   GermanLook Forums > Technical Section > Brakes

Reply
 
Thread Tools Display Modes
  #1  
Old March 24th 2024, 17:36
Tomas Tomas is offline
Registered User
 
Join Date: Aug 2018
Posts: 9
Brakes advise

I'm converting my 1303 to electric using a Tesla Small driveunit and therefore have to upgrade my brakes. Have got Porsche 944na spindles in front and rear arms from the same 944na. Can I use the rear 4-pot calipers from a 2003 Boxster at the front of my 1303 or is there better options? I also got the rear 944 brakes
Reply With Quote
  #2  
Old March 25th 2024, 00:02
owdlvr's Avatar
owdlvr owdlvr is offline
Administrator
 
Join Date: Sep 2008
Location: Canada - West Coast
Posts: 851
You have to look at the piston sizes, and do some calculations to figure out if you can use the 2003 Boxster rears upfront.

For my German Look, I'm running Boxster calipers on all four corners, fronts on the front. Rear calipers on the rear. The fronts use 944 hubs modified to my beetle spindles, and 1976 911 rotors. This mates up perfectly with the front calipers (with custom caliper mounts). On the rear I'm using 944 bearing retainers (which have the caliper mount built in), 944 turbo rotors, and the Boxster calipers. No mounts or adapters needed.

The piston sizes come into play with the Rally Bug. Currently it runs the 2-piston Ghia calipers (solid rotors) on all four corners. I have a set of 951 rear calipers coming off an Audi that I thought would make a great front brake update for the Rally Bug. BUT the combined piston area of the four piston Porsche rear caliper is smaller than the combined piston area of a 2-piston Ghia caliper. Thus, the car would end up rear biased. Can't use em.

So, for your rear boxster calipers on the front question, you need to do some piston math and compare them with your rear calipers. I use https://brakepower.com/piston-area-calculator.htm

-Dave
__________________
'71 Type 1 - Rally Project
'58 Type 1 - I bought an early!?!
'73 Type 1 - Proper Germanlook project
'68 Type 1 - Interm German 'look' project
'75 Type 1 - Family Heirloom
'93 Chevy 3500 pickup - Cummins Swap
Reply With Quote
  #3  
Old March 25th 2024, 00:12
Tomas Tomas is offline
Registered User
 
Join Date: Aug 2018
Posts: 9
Thank you owdlvr for your reply! Yes I might source front calipers also.
Reply With Quote
  #4  
Old March 25th 2024, 11:42
Tomas Tomas is offline
Registered User
 
Join Date: Aug 2018
Posts: 9
Still find it difficult to get the right parts, can someone please help me out what the options are? Boxster S calipers seems easier to get hold of. But which discs should I use if I go Boxster or Boxster S calipers? Using 944 spindles and 944 rear arms
Reply With Quote
  #5  
Old March 26th 2024, 01:09
owdlvr's Avatar
owdlvr owdlvr is offline
Administrator
 
Join Date: Sep 2008
Location: Canada - West Coast
Posts: 851
Boxster vs Boxster S rotors:

Non'S':
F Disc 298mm, Pistons in Calipers 2x40,2x36 mm , pad area 216 cm^2
R Disc 292mm, Pistons in Calipers 2x30,2x28 mm , pad area 196 cm^2
Thickness (new): 24mm front and 20mm rear

"S":
F Disc 319mm, Pistons in Calipers 2x40,2x36 mm, pad area 254 cm^2
R Disc 299mm, Pistons in Calipers 2x30,2x28 mm, pad area 196 cm^2
Thickness (new): 28mm front and 24mm rear

S rotors are thicker AND larger diameter.
S pads are larger
S calipers bolt in place of non S ones

Boxster S brakes are identical to Porsche 996 brakes.

But I don't know a front rotor that's going to work off hand for the S. For the regular boxster, it's easy. For the S I'd have to start going through them part for part.

-Dave
__________________
'71 Type 1 - Rally Project
'58 Type 1 - I bought an early!?!
'73 Type 1 - Proper Germanlook project
'68 Type 1 - Interm German 'look' project
'75 Type 1 - Family Heirloom
'93 Chevy 3500 pickup - Cummins Swap
Reply With Quote
  #6  
Old March 26th 2024, 08:48
Tomas Tomas is offline
Registered User
 
Join Date: Aug 2018
Posts: 9
Which mastercylinder do you use with the Boxster calipers?
Reply With Quote
  #7  
Old March 27th 2024, 00:47
owdlvr's Avatar
owdlvr owdlvr is offline
Administrator
 
Join Date: Sep 2008
Location: Canada - West Coast
Posts: 851
Presuming factory pedal setup. Empi Big-Bore master cylinder for disc brakes.

Yes. Seriously.

Pedal feel is spot on.
__________________
'71 Type 1 - Rally Project
'58 Type 1 - I bought an early!?!
'73 Type 1 - Proper Germanlook project
'68 Type 1 - Interm German 'look' project
'75 Type 1 - Family Heirloom
'93 Chevy 3500 pickup - Cummins Swap
Reply With Quote
  #8  
Old March 29th 2024, 09:13
412STi's Avatar
412STi 412STi is offline
Registered User
 
Join Date: Feb 2015
Location: Germany
Posts: 45
Quote:
Originally Posted by Tomas View Post
I'm converting my 1303 to electric using a Tesla Small driveunit and therefore have to upgrade my brakes. Have got Porsche 944na spindles in front and rear arms from the same 944na. Can I use the rear 4-pot calipers from a 2003 Boxster at the front of my 1303 or is there better options? I also got the rear 944 brakes
I hope you have also planned space for the Tesla on-board tools.

https://www.instagram.com/p/CwOqcvYIUxY/
__________________
----------------------------------------------------------
Greetings Gerold


STi powered Typ4 in the works...
R.I.P. 1302/'72
Reply With Quote
  #9  
Old March 29th 2024, 22:33
Tomas Tomas is offline
Registered User
 
Join Date: Aug 2018
Posts: 9
Quote:
Originally Posted by 412STi View Post
I hope you have also planned space for the Tesla on-board tools.

https://www.instagram.com/p/CwOqcvYIUxY/
Well I'm switching controlboard in the motor so there's not much Tesla electronic left. Batteries are from BMW i3.
Reply With Quote
  #10  
Old April 10th 2024, 23:40
flat flat is offline
Moderator
 
Join Date: Dec 2002
Posts: 676
I'm running BoxsterS on my 1302, stock master cylinder. I've done tons of Boxster setups on beetles too, using stock master (19mm) or the 20.6mm mentioned above. The 19mm engages about halfway down, but requires less pedal effort than the 20.6mm. You can also use a mk2 golf mc with adapter.

Boxster non S is preferred IMO, less unsprung weight. And for a bug you don't need the increased thermal mass/capacity of the S setup.

Here is the rotor and caliper info, all non-S model. The non-S calipers come in black from factory.

Calipers front:
Boxster 2.5/2.7 97-08
Cayman 2.7 07-08
986 351 421 03 left
986 351 422 03 right

Calipers rear
Boxster 2.5/2.7 97-16
Cayman 2.7 07-14
986 352 423 01 left
986 352 424 01 right

Rotor front (298*24mm)
Boxster 2.7 05-08
Cayman 2.7 07-08
987 351 401 01 left
987 351 402 01 right

Rotor rear (299*20mm)
Boxster 2.7 05-16
Cayman 2.7 07-16
987 352 401 01
__________________
www.vdubengineering.com
Instagram: vdubengineeringcanada
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 19:44.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
© www.GermanLook.net 2002-2017. All Rights Reserved