GermanLook Forums  

Go Back   GermanLook Forums > Technical Section > Suspension

Reply
 
Thread Tools Display Modes
  #1  
Old May 14th 2005, 03:01
KaferChris KaferChris is offline
Registered User
 
Join Date: Apr 2003
Posts: 50
944 N/A rear discs on IRS (again)

OK, new to the Porsche brake stuff...just searched and got 18 pages of former topics to read...and painfully did so, to arrive at several conclusions...if you'd be so kind to point out any errors or over-looked pieces please do.

For my `69 Std. Beetle with stock bug trailing-arms:

924S/944/181 stub axles (plan to run 181 drive flanges out of a Type I gearbox so I can use 100mm CV's T2/T4)
83-85.5 aluminum backing plates and longer M10x1,5 bolts
Singlepot calipers
289mm X 20mm vented rotors
Internal drum brake e-brake assembly, cable modification necessary (several ways)
Increases total trackwidth 52mm (26mm per side).
36mm wheel cylinders

I plan to use stock 'Ghia discs and a VW dual circuit M/C...but should there be a brake bias problem I may try the smaller 944 bore M/C - which I've read requires modification to the rear brake line since the circuits are backwards in comparison to the VW unit...and there's also some conflict with the VW stop light switches.

Can I use my Type III rear hubs which are already studded 5-130?

Any help is appreciated. Thanks in advance.
Reply With Quote
  #2  
Old May 14th 2005, 20:16
flat flat is offline
Moderator
 
Join Date: Dec 2002
Posts: 675
KaferChris,

You've done your research! Everything you mentioned is correct. Out of curiosity, keep in mind you can use your stock T1 stubaxles if you don't want to change your axles. You will also need the 944 rear hubs. The T3 hubs are not easily adapted without machining. It's easier to get the 944 hubs.

As for the rear bias:
The 944 master cylinders are typically 23mm/19mm. That is 23mm in the front circuit, 19mm in the rear. If you are going to use a stock T1 MC, then you should be alright as far as hydraulics is concerned because T1's are 19mm/19mm. It's difficult to calculate brake torque from a given hydraulic pressure in a drum system because of the leading/trailing shoe arrangement. Also, leading shoes in a drum system have a 'servo' action. Check here for more hydro info:

http://www.vdubcustoms.com/Tech/tech_brake.htm


I think you are on the right track, and if anything you hay have a little too much rear bias. You always want to setup a vehicle so that the front tires lock a LITTLE earlier that the rears on panic stops. Understeer is easier to control than oversteer. If you have too much rear brake, then you can add a proportioning valve to the rear circuit and fine tune your vehicle. There are lots of variables here (weight distribution, tire size, tire quality, weight transfer, suspension setting etc) that play a role here. I think you're on the right track.

One question though, why 944 brakes on the back on not on the front?

Easy,
Lanner
__________________
www.vdubengineering.com
Instagram: vdubengineeringcanada
Reply With Quote
  #3  
Old May 14th 2005, 21:26
KaferChris KaferChris is offline
Registered User
 
Join Date: Apr 2003
Posts: 50
Lanner,

First off, thanks.

I built the front-end months ago and have been working on my rear suspension lately...I've got complete Type III rear brakes done-up for the car (sandblasted and painted every last piece, all new everything), but I guess the idea of not adjusting brake shoes is just too tempting...so I threw those on one of my other cars.

I figure I'll get the car running using the stock VW disc assemblies on the front, and perhaps upgrade to 944 4-pots and vented rotors in the future...

Doing all the 944 brakes will also get me away from my ~1" spacers all the way around. I was using Boxster 16" split 5-spokes (16x6 ET50's and 16x7 ET40's) but have recently picked-up some C2/C4 16" 5-spokes (16x7 ET55's and 16x8 52's).

I plan to upgrade to either Type IV CV's with the appropriate machining or Type II CV's since I'll probably one day want to put ~150-175hp down...aiming for ~120hp for now with a mild 2017.

Thanks again,
Chris
Reply With Quote
  #4  
Old April 9th 2006, 18:23
KaferChris KaferChris is offline
Registered User
 
Join Date: Apr 2003
Posts: 50
Thanks again for the advice and parts.




Last edited by KaferChris; April 17th 2006 at 02:52.
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 22:38.


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