993 master cylinder and servo 'upgrade'
#1
Three Wheelin'
Thread Starter
993 master cylinder and servo 'upgrade'
Hi guys,
I know a few of you have converted your C2 964 over to use the 993 MC and servo and the process is well covered.
My question is, is it worth while?
With my MC now 25+ years old I have no idea how much longer it will last. A replacement is stupidly expensive where-as the 993 item is not. In the spirit of pre-emptive maintenance, if you're going in there to swap it out, why not convert to the 993 item?
I have std 964 4 pot calipers up front and 993 C4 rear caliper on the rear with the appropriate PV valve. (car still feels under braked on the rear axle)
What are the physical pros/cons of this?
Anybody know the MC bore sizes of each?
Does the 993 servo offer greater mechanical advantage than the 964 servo?
Thanks
Rob
I know a few of you have converted your C2 964 over to use the 993 MC and servo and the process is well covered.
My question is, is it worth while?
With my MC now 25+ years old I have no idea how much longer it will last. A replacement is stupidly expensive where-as the 993 item is not. In the spirit of pre-emptive maintenance, if you're going in there to swap it out, why not convert to the 993 item?
I have std 964 4 pot calipers up front and 993 C4 rear caliper on the rear with the appropriate PV valve. (car still feels under braked on the rear axle)
What are the physical pros/cons of this?
Anybody know the MC bore sizes of each?
Does the 993 servo offer greater mechanical advantage than the 964 servo?
Thanks
Rob
#2
Burning Brakes
I think it gives a slightly higher boost ratio and is a tight fit. New mounting brackets needed and I think the hydraulic fitting sizes are different m10/m12 iirc.
http://forums.pelicanparts.com/porsc...nalysis-7.html
http://forums.pelicanparts.com/porsc...nalysis-7.html
#3
Not sure if it's worth it with the calipers you have. I've got 996turbo fronts and the old fronts on the back of mine and while it worked with the standard 19mm mastercylinder the pedal travel was excessive, surprisingly the pedal feel and modulation is greatly improved on mine even though the booster is bigger! It is a tight fit and the bracket had to be modified with the rs front roll bar but apparently go straight on with the standard arb.
#5
Hi guys,
I know a few of you have converted your C2 964 over to use the 993 MC and servo and the process is well covered.
My question is, is it worth while?
With my MC now 25+ years old I have no idea how much longer it will last. A replacement is stupidly expensive where-as the 993 item is not. In the spirit of pre-emptive maintenance, if you're going in there to swap it out, why not convert to the 993 item?
I have std 964 4 pot calipers up front and 993 C4 rear caliper on the rear with the appropriate PV valve. (car still feels under braked on the rear axle)
What are the physical pros/cons of this?
Anybody know the MC bore sizes of each?
Does the 993 servo offer greater mechanical advantage than the 964 servo?
Thanks
Rob
I know a few of you have converted your C2 964 over to use the 993 MC and servo and the process is well covered.
My question is, is it worth while?
With my MC now 25+ years old I have no idea how much longer it will last. A replacement is stupidly expensive where-as the 993 item is not. In the spirit of pre-emptive maintenance, if you're going in there to swap it out, why not convert to the 993 item?
I have std 964 4 pot calipers up front and 993 C4 rear caliper on the rear with the appropriate PV valve. (car still feels under braked on the rear axle)
What are the physical pros/cons of this?
Anybody know the MC bore sizes of each?
Does the 993 servo offer greater mechanical advantage than the 964 servo?
Thanks
Rob
the feel at the pedal is higher and harder w/ the 993 booster, most consider this to be desirable.
w/ oe 964 front and 993 rear you have a nearly ideal brake bias for a lowered stiff car w/ effective lsd
bias below p/v knee/bias above p/v knee
964 4/4 is 1.734/3.210
964 4/2 is 1.508/2.793
964 4/993 4 is 1.42/ 2.629
911 Carrera 2.7 1.491
#6
Not sure if it's worth it with the calipers you have. I've got 996turbo fronts and the old fronts on the back of mine and while it worked with the standard 19mm mastercylinder the pedal travel was excessive, surprisingly the pedal feel and modulation is greatly improved on mine even though the booster is bigger! It is a tight fit and the bracket had to be modified with the rs front roll bar but apparently go straight on with the standard arb.
#7
RL Technical Advisor
I would certainly upgrade the MC to the 993 one with those calipers.
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#9
#11
1) bias approaches 1, you have way to much rear and the rears will tend to lock first.
2) front 964 rotor want 26-28mm thick rotors, 26mm is the minimum, rear 964 rotors are 24mm when new.
#12
Not to worry though as 964 C4 comes w/ a stock 23.8mm m/c, same size as that used on the 993C2. An upgrade here would be to use the 964 RS/t mc which is 25.4mm
#13
After running this setup for a while I'd agree with you regarding the rear bias, it has cpught me out on the track before when trail braking into turns! I'm already on the lookout for a set of 993 c2 4 pots. Regarding the disc thickness issues my pads are changed at 50% wear so considered it a mute point.
#15