early 944 brakes, stock MC....dosent feel right

[super vw]

So, s-beetle or 944 MC?

[Jeza]

Jonathan

Sorry I havn't come back with any more info, the car is requiring some rust repair, and I have been waiting to borrow a welder. I say the car will be back on the road soon, but not being the worlds fastest worker it is likely to still be a couple of months.....

However I would go 944 MC (In fact that is what I have done ) , and from comments on this thread and others that would be the general consensus for the best MC to match the 944 NA brakes.

Good luck

Cheers
Jeremy

[Angelo Amato]

I found a WONDERFUL www for us brake-a-holics !

see my other posting under brakes !

ENJOY !

[judgie]

just to let you know ,i used the 944[19/23]master and 944 n/a brakes.
19 to the front and 23 to the back.no dive on brakeing very hard and stops very very well indeed thank you,i think the wheel selection makes a big differance in brake perfomance as well ie;i run 7x16 with 205/55/16 on the front and 8x16 with 225/50/16 on the back so my trye split also helps with the rearwood brake bias.
cheers rob

[Che Castro]

I had a look at shad's calculations. how come there is no multiplier for the number of pistons in the caliper?

[Jeza]

Originally Posted by Che Castro

I had a look at shad's calculations. how come there is no multiplier for the number of pistons in the caliper?

Good question!

I can't say as I know the answer to that, but hopefully some activity on here will lure in a hydralics / fluids engineer to answer


Cheers
Jeremy

[Wally]

AKAIK, the two pistons in a 4-pot caliper are never the same diameter, so you must simply add the two of them. Surface is surface after all.

Greetings,
Walter

[Jeza]

Wally

I think Che might have been refering to the 2 pistons such as in a standard ghia calliper with 2 40mm pistons.

Some one in our club explained it to me a while back but I completely forget it now. However there was something about just using the area of one piston for some reason.

Cheers
Jeremy

[super vw]

Well, i just got my hands on a early 911 (73 targa) MC. i mounted it up, but have not plumbed it yet (still waiting on parts). it bolts right in. i think i is a 19mm?

anyways, i will give this a try to see how the pedal feels once i get it plumed up. If this dosent work out. i will try to find a used 944 MC to try. i want to find the best "bolt on" option, and it seams like a lot of porshe stuff shares the same mounting holes.

[Che Castro]

Yep i was referring to the post that was linked on one of the earlier pages.

What I didnt get was why the number of pistons on each caliper wasn't included.

[VWader04]

has anyone used or heard about using the
CSP #611 015 000
i heard some where that this would be a good option...but, i don't know though..im in the same boat as everyone else

20.64mm bore CSP master cylinder

[Vdubjim]

accoarding to pelican parts the 911 (up to 89) MC is only 19mm but maybe the volume is more??

and if using the 944 MC which one? there are like 4. EXPENSIVE!!!

Master Cylinder For Use With Girling Brake Booster, 944 (1983-86), 924S (1987-88), Each [Photo]
E-355-011-00 $221.55

Master Cylinder For Use With ATE Brake Booster, 944 (1983-86), 924S (1987-88), 944 Turbo (1986), Each
E-355-011-01 $140.20

Master Cylinder For Use With Girling Brake Booster, 944/944S (1987-88), 944S2 (1989-91), Each
E-355-011-10 $258.30

Master Cylinder For Use With ATE Brake Booster, 944/944 Turbo (1987-88), 944S/S2 (1987-91), 968 (1992-95), Each

Also maybe this helps? no pics though. I kow that jettas and stuff have a proportioning valve that basically screws into the MC wonder if this is the same? too bad its NLA.
Brake Pressure Regulator, 944 (1985-91), 944 Turbo (1986-89), Each

[Tim]

Hello VWader04,
I am using the CSP 20.64mm m/c but it is used with the Kerscher front brake kit and the reinforced rear cylinders from CSP. I feel better front/rear brake bias and firmer/shorter pedal with the CSP m/c than the stock vw m/c (was used with the Kerscher front kit).

[Vdubjim]

i wonder what car that is from?

[MattKab]

First of all Happy new year to all!

Shad's formula is standard textbook mechanical advantage formula. As Shad mentioned in his post, we are fortunate, in that we can use the formula in it's stripped down, simplified version. We can ignore factors like friction, radial differences front to rear, pad area, etc. as these can be considered to be constants

Like Wally, I still have the 3/4" T1 m/c and 40/36mm & 30/28mm Brembos (~15,000miles)

I got to a value of 1.72 to the front and I had 1.23 as the bias of NA 944 rears/T1 front and a T1 m/c.


If we had the 1986 only 944T Front calipers with their 36/34mm pots, we would have a bias of 1.45

This compares very well to the stock NA 944 with the Ate calipers bias of 1.44

Now compare this to the very earliest 911 which had a bias of 1.88 for the first year. This was then changed to 1.6

By lengthy mathematic (plus assumptions) I get the T1 front/CB roto hub and stock m/c to have a bias of 1.38

I put Al B's gold custom Bug (with the cool 'flame' wheels and ALL new parts) on our Arex computer test lane and I recorded stock T1discs/drums and m/c to have a bias of 1.57

I have 'invented' an m/c that can be 'made' for our Brembo 4pot systems that will yield a bias of 1.47...

If I fitted the Kerscher split bore m/c my bias would be down to 1.3

m/c bore has no affect on bias, just the leverage ratio.

Feel free to challenge my values, I still have the pages of arithmetic I used. Plus many possible configurations, feel free to ask.



Matt