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

[Wally]

Originally Posted by Jeza

It a leverage thing, if you increase the diameter of the slave cylinder in relation to the mc you increase the power to the brake.

I agree; it also complies with the formula Shad used.

Increasing the MC diameter will increase the hardness of the pedal but not the power to the brake.

Now that doesn't comply with the leverage formule from Shad!. Tho I think you are very right about the hardness aspect of the pedal thingy.

What you have now is probably a very good ratio for a rear engined car.

Yeah, I agree. Probably safer also in extreme situations than an even lower ratio.

The 944 brakes with the 944 MC gives a ratio of 1.41, which I reckon will probably work quite nicely.

Cheers
Jeremy

Yes, I agree, but the mean reason for the calculated relatively low ratio (for a front engined 944) is that the 23mm (IIRC its 21mm, not 23 mm like in the thread where Shad chimes in, but lets use 23mm for calculations sake) front m/c cup diameter is in the lower part of the equation, thus decreasing the slave/master ratio of the front brakes!!!!!!!
i.e. : 944 fronts:
(54mm caliper cup diameter / 23 mm front m/c cup diameter)²= 5.51
944 rears:
(36mm rear caliper cup / 19.06 mm rear m/c cup diameter)²= 3.57
F/R ratio would then be 1.54
With a 21/19 m/c the ratio would be even higher at (54/21)² / (36/19)² = 1.85.
THATS the point I a trying to make in this equation:
The bigger the front cup of the m/c, the more REAR biased the set-up gets!!!!

Therefore, 180 degrees from my beliefs before, to get a more rear biased set-up from the stock front setten-up 944 brake system, you DO NOT install the stepped m/c the other way around: i.e. 19mm side to the front and the 21/23mm side to the back. That would worsen the problem.
The above holds only true of course IF Shads formula is correct (and 'knewing' Shad, he is quite an educated guy (even then), so I must really believe him)

Jeremy, I am realy curious what your or others thoughts are about my above 'conclusion'. True or false?

This would also explain the enormous front biased'ness' of my current 944 turbo Cup brake set-up on my 1303 SB with the stock 19/19 m/c ! I think I need the biggest step m/c (23/19?) I can find and maybe additionally a bit smaller front calipers or a front propotioning valve (if possible).

PS have you done brake performance comparisons or is it just a feel thing when you mention your 1303's powerful brakes?

No, just a feel thing, but when I drove that car every day back then, I was very aware of any change, even the very subtle ones and this wasn't subtle, but a very, very strong brake action. You can only draw the conclusion that stock bugs are set-up very very conservative with rear break bias.

Greetings,
Walter