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> 23 mm Master cylinder?, From a 930?
HalfMoon
post Oct 31 2017, 08:46 PM
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A friend of mine who owns a race shop that does alot of Porsche work said when queried about reducing travel on the 914 brake system that the 23mm master cylinder from a 930 would far better reduce the travel over a 19mm master cylinder.
Has anyone done this mod and if so, what were the performance gains/differences?
Thanks
D
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HalfMoon
post Oct 31 2017, 10:55 PM
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To clarify-

I run a 19mm too (as well as a variety of other big brake mods). The primary question I'm pursuing isn't brake "power" (performance gains/differences is/was ancillary), rather it's about "less pedal travel".
That's what the inquiry is really about as well as the advice I had been given.
So I guess the question is for folks who have ACTUALLY done the modification to a 23mm and if they have obtained less pedal travel as a result.
Not asking about theory or opinion, asking about actual experience. Many of us have done the 19mm change and their's reams of information on that mod but not much about the 23mm and pretty much nothing in terms of actual experience.
The main thrust of the question is "brake travel".
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mepstein
post Nov 1 2017, 05:30 AM
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QUOTE(HalfMoon @ Nov 1 2017, 12:55 AM) *

To clarify-

I run a 19mm too (as well as a variety of other big brake mods). The primary question I'm pursuing isn't brake "power" (performance gains/differences is/was ancillary), rather it's about "less pedal travel".
That's what the inquiry is really about as well as the advice I had been given.
So I guess the question is for folks who have ACTUALLY done the modification to a 23mm and if they have obtained less pedal travel as a result.
Not asking about theory or opinion, asking about actual experience. Many of us have done the 19mm change and their's reams of information on that mod but not much about the 23mm and pretty much nothing in terms of actual experience.
The main thrust of the question is "brake travel".

The change in pressure and travel when you go to a larger MC isn't theory or opinion. Its a relationship/ratio between the size of the MC and size of the piston calipers. If you keep the calipers the same but increase the size of the MC, the MC will move more fluid with less pedal travel but at the same time, you will need more pressure on the pedal to achieve the same braking force at the caliper. Just like sitting on a see saw, shorten the lever on your side and it gets harder to lift the other end but the travel on your end is shorter. Go too short and at some point, you don't have the force available to move the lever. You also have to make sure the ratio front to back is correct. Its not just about going big, it's about the correct balance.

You won't see much information on World about 23mm MC's because most of the cars simply can't use a MC that large unless they've also switched to very large calipers.
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Posts in this topic
HalfMoon   23 mm Master cylinder?   Oct 31 2017, 08:46 PM
Vacca Rabite   A friend of mine who owns a race shop that does a...   Oct 31 2017, 09:32 PM
HalfMoon   A friend of mine who owns a race shop that does ...   Oct 31 2017, 10:05 PM
porschetub   A friend of mine who owns a race shop that does a...   Oct 31 2017, 10:19 PM
Mike Bellis   I'm running a 23 but I also have 930 brakes. I...   Oct 31 2017, 10:39 PM
HalfMoon   I'm running a 23 but I also have 930 brakes. ...   Oct 31 2017, 10:56 PM
shoguneagle   Agree with all the above. I am running 23mm M/C w...   Oct 31 2017, 10:52 PM
HalfMoon   Agree with all the above. I am running 23mm M/C ...   Oct 31 2017, 10:57 PM
HalfMoon   To clarify- I run a 19mm too (as well as a variet...   Oct 31 2017, 10:55 PM
mepstein   To clarify- I run a 19mm too (as well as a varie...   Nov 1 2017, 05:30 AM
jd74914   To clarify- I run a 19mm too (as well as a vari...   Nov 1 2017, 05:49 AM
mepstein   [quote name='mepstein' post='2544209' date='Nov 1...   Nov 1 2017, 05:58 AM
HalfMoon   To clarify- I run a 19mm too (as well as a vari...   Nov 1 2017, 10:02 AM
mepstein   [quote name='mepstein' post='2544209' date='Nov 1...   Nov 1 2017, 11:36 AM
porschetub   [quote name='mepstein' post='2544209' date='Nov ...   Nov 1 2017, 04:59 PM
infraredcalvin   It’s not a 930 MC is a 23 mm ATE MC for a Merced...   Oct 31 2017, 11:50 PM
infraredcalvin   Sorry had to edit above...   Oct 31 2017, 11:55 PM
flyer86d   My old 911SC track car had turbo brakes front and ...   Nov 1 2017, 05:30 AM
DBCooper   And, important to note, with just a larger m/c you...   Nov 1 2017, 08:28 AM
Racer Chris   We just swapped out a 23mm M/C for a 22 mm VW unit...   Nov 1 2017, 09:04 AM
HalfMoon   We just swapped out a 23mm M/C for a 22 mm VW uni...   Nov 1 2017, 10:05 AM
mgp4591   We just swapped out a 23mm M/C for a 22 mm VW uni...   Nov 1 2017, 11:05 AM
Racer Chris   Is that the M/C for the Corrado that you swapped ...   Nov 1 2017, 11:07 AM
tomeric914   20.64mm or 22.22mm Master Cylinder Option How-To t...   Nov 1 2017, 07:03 PM
HalfMoon   20.64mm or 22.22mm Master Cylinder Option How-To ...   Nov 2 2017, 05:38 PM
Racer Chris   20.64mm or 22.22mm Master Cylinder Option How-To...   Nov 2 2017, 07:08 PM
tomeric914   David, This is basic hydraulics, but somehow, too...   Nov 2 2017, 07:54 PM
HalfMoon   David, This is basic hydraulics, but somehow, to...   Nov 2 2017, 11:48 PM
Keyser Sose   I currently run a 19mm and find that their's s...   Nov 3 2017, 10:56 AM
Racer Chris   the bias valve can make it hard to get them full...   Nov 3 2017, 03:03 PM
Keyser Sose   the bias valve can make it hard to get them ful...   Nov 3 2017, 03:37 PM
Racer Chris   So do those valves ever go bad? They don't ...   Nov 4 2017, 09:06 AM
tomeric914   THIS IS AN EXAMPLE ONLY!!! You need t...   Nov 3 2017, 03:04 PM
DBCooper   OK, when I got my car the pedal was way too hard. ...   Nov 1 2017, 10:34 AM
Dave_Darling   When you change the diameter of the master cylinde...   Nov 1 2017, 09:48 PM
tomeric914   ...on a bone stock brake system When you change ...   Nov 2 2017, 08:39 AM
Dave_Darling   ...on a bone stock brake system No, that's ...   Nov 2 2017, 12:07 PM
tomeric914   The reason for going with a larger master cylinder...   Nov 2 2017, 07:36 PM
SirAndy   When you change the diameter of the master cylinde...   Nov 2 2017, 11:19 AM
porschetub   When you change the diameter of the master cylind...   Nov 2 2017, 06:59 PM
GeorgeRud   Is the lack of a proportioning valve on the 911s b...   Nov 4 2017, 09:19 AM


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