Tracy;
Well, not entirely. I guess you will have to re read a little more
carefully:
Hear is a couple of passages that refute your conclusions from that URL:
"The first problem with silicone has to do with the concept of boiling
point. Boiling point is a very good metric for evaluating glycol based
fluids because it roughly represents the conditions under which glycol turns
compressible. It is a very poor metric for evaluating silicone based fluids
because
<<<<<<<they turn compressible at a lower temperature than that at which they
boil>>>>>>>.
It is not clear that a DOT-5 silicone fluid has anything to offer relative
to a good DOT-4 fluid once this is taken into account (at least with regards
to the boiling point.)"
Another section that has to be read carefully:
To continue to belabor the silicone brake fluid question ... Just discovered
a brochure in my pile of karting information from the Ripley Engineering
folks ... they make braking systems for karts. Here's what they say about
silicone brake fluid: "unsuitable for racing applications (for these three
reasons): 1. At approximately 275 degrees, the additives used to compound
silicone fluid begin gassing off resulting in air in the lines.
<<<<<2. At elevated temperature, silicone fluid has four times the
compressibility of glycol-based fluids (leading to) increased pedal travel
and a spongy pedal>>>>>.
3. At elevated temperatures, silicone brake fluid will expand significantly.
"
Here is another page that actually lists the "general" compressibility of
silicone fluid:
http://www.unitedchem.com/intro.htm
One claim is that silicone fluids, in general, exhibit "high
compressibility".
In the section "Mechanical" is quoted a co-efficient of compressibility and
under that same heading is a factor of compressibility at various pressures.
At 1,000 psi it is less then 1% but grows to over 5% at 10,000 psi.
I believe those are pressures far exceeding those in braking systems but it
does go to the proof that the base stock tends to have greater
compressibility then conventional brake fluids.
Racer Robb
-----Original Message-----
From: SlyFoxRc@aol.com [mailto:SlyFoxRc@aol.com]
Sent: Thursday, February 11, 1999 4:02 PM
To: rsmith@bfmni.com; autox@autox.team.net
Subject: Re: Tiny bubbles...o...o....o....o.....o...
In a message dated 2/9/99 4:24:31 PM Pacific Standard Time, rsmith@bfmni.com
writes:
<< Yes I have heard the same thing about silicone based brake fluids.
Something
about the compressibility of the base fluid. >>
Racer Robb:
I went to the URL you listed and read what it had to say about the
"compressibility" of brake fluid. As I suspected it was talking about
the compressibility of the fluid after it reaches it's boiling point, hence
introducing gas (which is compressible) into the fluid. It went on to say
that with silicone fluids it is hard to deliver the fluid into the system
without introducing air bubbles at the same time, once again adding
to the compressibility of the fluid. My point earlier was that the fluid,
be
it glycol based or silicone based is not compressible in its fluid state,
only
when it has boiled or had some form of gas introduced into it.
Tracy Sandberg
Sly Fox Racing
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