VW Front Discs + 944NA Rears? (on a 1303)

[WD-40]

Heya.

I've been doing a lot of reading and a lot of searching. I've found a few references to this particular setup, but nothing involving too much detail.

What I'm considering doing for my 1303 is using the front disc brake kit from CB for the front (basically VW, but studded to the Porsche pattern), and the rear vented disc brakes from the NA Porsche 944.

It seems like it would have a lot of advantages:
* lighter weight up front for better road handling- many remark that the front 944's are overkill, and HEAVY.
* Rear swap is brutally easy, and way cheaper than any aftermarket disc setups.
* Rear track is increased (I want this) while front is not (or at least, very minimal).
* Front is VERY cheap to do.
* Very few "custom" parts overall. (no new ball joints or billet hubs)
* No camber issues (like 944 front spindle swap).
* almost all friction parts are off-the shelf and easy to find if you need them.


I already have the full 944 brake set... but am considering the above plan instead of the 944 fronts. The only thing holding me back is that I don't know how the proportioning would work out, and what master cylinder would work the best. I don't know the formulas, and won't endanger my life by pretending to know what I'm talking about when I don't.


So someone please tell me why this won't work... or better yet, tell me why it will! This is one of my last big hurdles with this car....


Thanks
- David

[ricola]

I used that set-up on my speedster replica while i was sorting out the front 944s, to be honest it was the best balance of all the combinations I used, better than with the 944 fronts and I used the stock m/c. I'm sure my front end was relatively lighter than a bug but I have seen it done before with no concerns...

Rich

[Jeza]

My only concern with that setup is that you have large vented rotors on the rear and small solid rotors on the front.

This means that the rears can absorb a LOT more heat than the fronts can.

So if you are pushing the car hard (Track or Targa type racing) you may find that the fronts become unresponsive, causing you to work the pedal harder and then the rears are more prone to locking under certain conditions.

It is a rear engined car so you can afford more brake power on the rears than most cars out there, but you still have to be careful, things get "taily" with too much rear brake.

You should be able overcome this with a bias valve plumbed into the rear line and set appropriately.

Cheers
Jeremy

[WD-40]

Thanks for the replies.

Jeza-
Good observation. But theoretically, the only time that would happen is if I pushed hard enough for the fronts to fade. In that sort of situation, if I had solid discs on all four corners (or, the disc/drum combo) I would most likely not have ANY brakes!! (right?)

Has anyone run the solid discs and had many problems overheating them?


Thanks
- David

[Jeza]

There are ways around this occuring such as a proportioning valve in the rear line.

Careful selection of pads for front and rear might help. Drilled or slotted front rotors (that are still solid) may help to. Best to talk with a brake shop and see if they have any suggestions.

Cheers
Jeremy