Ferrari Mailing List: Re: 328gt4

[Dennis Liu (BigHeadDennis]

Grahame wrote:

<description of cool motor transplant snipped>

>By the way, here is a technical question - anybody using silicon brake
fluid? What is your experience of this?  

=================

Grahame, welcome to the Flist, and please send along a link to some photos
of your baby - quite the feat, it sounds like!  The GT4 is well known for
handling very well (better, arguably, than the 308 successors), so stuffing
the 328 motor in there sounds like the car much just fly now.  Cool!

Re your brake fluid question:

In the US, DOT 3, DOT 4 and DOT 5.1 (NOT DOT 5!) brake fluids are
glycol-based compounds (they are compatible with one another) and are
"hygroscopic", which means they absorb moisture from the air. Formulations
between DOT 3 and DOT 4 are the same, except boiling points (wet and dry)
are different. DOT 3 is used on a lot of vehicles, as it is somewhat
cheaper. DOT 5.1 is relatively new, and has higher boiling points, I
believe.

DOT 5 (NOT DOT 5.1!) brake fluid is silicone-based, is not hygroscopic, and
should never be mixed with DOT 3, DOT 4 or DOT 5.1. DOT 5.1 has the same
boiling point as DOT 5, but is not silicone-based. (Interestingly, DOT 5
fluid will not damage paint.) Restoration shops like to use DOT 5 because
the show queens they produce usually just sit, or else are driven on and off
trailers, possibly on nice Sundays. DOT 5 does not need to be changed as
frequently, because it's not hygroscopic, so it's one less maintenance issue
for them.

Few (if any) manufacturers today sell cars that come with DOT 5 silicone
brake fluid (I think Harley Davidson does). The only way to convert to
silicone is to completely purge the glycol (DOT 3, 4 or 5.1) brake fluid
from the system. The number one reason NOT to use DOT 5 silicone is because
it can provide a slightly mushy pedal feeling. 

Which fluid to use, then? Stick with DOT 4, which is what I suspect Ferrari
recommends.

Overall, Castrol SRF is the best, hands down, but is insanely expensive.
Ford HD (available from your local dealer) is probably the best value, if
you're a track junkie and are going to be changing the fluid frequently (who
cares what the WET boiling point is if you're changing the fluid before
every track event?). I personally use ATE Super Blue and Super 200 -- same
exact formulation, just different colors. One is blue and the other is
yellow. This way, when I bleed my brakes, I can better see what is new and
what is old. One can find them for about $12 a can, and I use 1 can per
change (heck, when I'm bleeding brakes, I flush the fluid entirely, as it's
cheap insurance).

Here's a chart of Heavy Duty Brake Fluids (www.SeineSystems.com):

Brand DOT Rating Dry Boiling Wet Boiling
----- ---------- ----------- -----------
AP Racing 550 DOT 3 550°F (287°C) 284°F (140°C)
AP Racing 600 DOT 3 572°F (300°C) 284°F (140°C)
(not compatible with other fluids)

ATE Super Blue DOT 4 536°F (280°C) 382°F (194°C)
ATE Super 200 DOT 4 536°F (280°C) 382°F (194°C)
(amber color aka Type 200)

Bosch DOT 3 DOT 3 491°F (255°C) 288°F (142°C)
Bosch DOT 4 DOT 4 509°F (265°C) 329°F (165°C)
Bosch DOT 4+ DOT 4 536°F (280°C) 356°F (180°C)
Castrol LMA DOT 4 446°F (230°C) 311°F (155°C)
Castrol SRF DOT 4 590°F (310°C) 518°F (270°C)
Ford HD DOT 3 550°F (287°C) 284°F (140°C)
Motul Racing DOT 4 586°F (307°C) 421°F (216°C)
Brake Fluid 600

Performance DOT 3 550°F (287°C) 284°F (140°C)
Friction Z-Rated 

Wilwood 570 DOT 3 570°F (299°C) 284°F (140°C)

Minimum spec. for DOT Rating Dry Boiling Wet Boiling 
DOT 3 401°F 284°F
DOT 4 446°F 311°F
DOT 5 500°F 356°F


Hope this helps!

Vty,

--Dennis