master cylinder

[hoggie]

Is there a master cylinder that i can fit to my 325 that will boost braking performance i was thinking that i might upgrade to wms keri frnt brakes the master cylinder that would not need any change fittings i think i saw here before something about a golf master cylinder that

[Brianmoooore]

There's no such thing as an 'upgrade' for a master cylinder. You can always trade fluid displacement for length of travel, by changing bore size, but this gives you a range between a short heavy pedal or a long lighter one. You just have to find an acceptable compromise, based on the amount of assistance available when you add your chosen servo.
If, however, you change the brake callipers for one's with larger pistons, then a master cylinder with a larger bore will also be needed to keep the length of pedal throw at your chosen compromise.
The Golf servo (not cylinder) 'upgrade' you have seen (now superseded by the Clio servo 'upgrade') is actually a downgrade, and is used when fitting a 24 valve six cylinder engine into an E30, as the inlet manifold on these engines fouls part of the space where the standard servo fits.

[hoggie]

Thanks brian

[jmc330i]

Brianmoooore - just curious as to why the Clio servo is a downgrade over the standard servo? I was much happier with my brakes after fitting a clio servo, with both the standard E30 and 25mm master cylinders.

[mrLEE30]

probably because fitting anything French is a downgrade, even to a Chinese car!

[Brianmoooore]

On the couple of M5x conversions I've done to E30s, I've retained the standard E30 servo (by moving it sideways), so I don't actually have any experience of the Clio servo.
However, I know the Golf servo provides considerably less assistance than the E30 version, atmospheric pressure remains roughly at 15 P.S.I., and the laws of physics haven't changed in the last twenty years or so, so I'd still expect a reduction in assistance from the Clio unit.
As I wrote in my last post, it's all a balancing act between pedal pressure, pedal length and the available assistance from the servo used, and that's before considering things like stepped bore master cylinders which apply different pressures to the two brake circuits.
Apart from the latter, used to achieve front/rear balance, non of this actually 'improves' the brakes - just the feel of them.

[jmc330i]

probably because fitting anything French is a downgrade, even to a Chinese car!

I definitely agree with the Golf servo - I've used both the Mk1 GTi and Mk2 1.3 servos and they were not great at all. But I was much happier with the Clio servo fitted - I guess it could be down to comparing an old 'worn' E30 servo to the much newer Clio one. Do servos deteriorate over time??

[keri-WMS]

Master cylinder piston area and caliper piston area just creates a ratio, think of it as a lever.

Put bigger pistons at the caliper, and a bigger piston at the master and in effect you have made both ends of the "lever" longer. This acheives nothing, you are at square one!

You can go two ways (changing the ratio, by either caliper or master):

1 - Longer/softer pedal and more assistance
2 - Shorter/harder pedal and less assistance

For what it's worth, our kits have either 1.25" pistons which give you 87.5% of the standard caliper area (on a bigger disc) for better feel, or there's the optional 1.38" size which is 106.6% of standard for people who want more front bias. Neither require a bigger master cylinder....

[redcar]

On the couple of M5x conversions I've done to E30s, I've retained the standard E30 servo (by moving it sideways), so I don't actually have any experience of the Clio servo.
However, I know the Golf servo provides considerably less assistance than the E30 version, atmospheric pressure remains roughly at 15 P.S.I., and the laws of physics haven't changed in the last twenty years or so, so I'd still expect a reduction in assistance from the Clio unit.
As I wrote in my last post, it's all a balancing act between pedal pressure, pedal length and the available assistance from the servo used, and that's before considering things like stepped bore master cylinders which apply different pressures to the two brake circuits.
Apart from the latter, used to achieve front/rear balance, non of this actually 'improves' the brakes - just the feel of them.

So why is the Clio servo a downgrade?

[Brianmoooore]

so I'd still expect a reduction in assistance from the Clio unit.

[hoggie]

So I pressume using competition fluid over standard fluid gives no extra gain

[BadDave]

So I pressume using competition fluid over standard fluid gives no extra gain

All it does is increase the boiling point,and require more frequent fluid changes as it has a tendency to absorb moisture more quickly.

[hoggie]

So for track use if you are redlining the car?

[BenHar]

Don't understand the question, sorry.

There is no direct link between "redlining the car" and how the brakes work.

Ben

[hoggie]

what I mean is if your using it on a track or fast road or doing alot of heavy braking

[Grrrmachine]

None of them increase the braking force, no. They just make the brakes last longer before fading, but at the cost of needing more frequent changes.

Have a good read of this:

http://www.e30zone.net/e30zonewiki/inde ... s#Upgrades