Re: dual single-circuit vs. single dual-circuit

[bearbvd@domain.elided (Greg Hermann)]

>
>Right. IIRC, the "dual single masters" was Alfa's response to the dual braking
>circuit requirement using the existing floor pedal to actuate the slave/masters
>up in the engine compartment. I never looked at it that closely and thought
>it was pretty silly, but it did the job until they could get the "real"
>dual master online.

I think folks here have been a bit quick to call the dual -single master
cylinder brake set-up (with dual boosters) a bad design. Yes, it is costly.
Yes, it has more parts. BUT--it IS a true redundant braking system, and it
is, in fact, missing some of the failure modes that can take out all
braking with the tandem dual circuit masters!

Another feature--is that it is FAR easier to get front/rear brake
proportioning (and limiting, or progressive limiting, if needed) spot on
where you want it with a dual single system. Jag did this for years with a
balance bar between the two single masters, as do MANY race cars. It is not
too complicated or expensive at all to make said balance bar user
adjustable, and you also have the option of using masters with two
different piston diameters, also the option of using boosters with two
different power diaphram diameters, or boosters with different numbers of
diaphrams in tandem. (If you doubt that this is done, take a peek at a
Bendix catalogue for medium duty truck brake system components before you
voice your doubts!)

Wilwood, for one, is now selling a dual single master set-up with an
adjustable balance bar for racers.

The dual single system is definitely a more elegant engineering solution
than a tandem dual circuit master, not a stop gap! Comparing the two is
kind of like comparing a dry sump to a wet sump engine oiling system. More
foolproof, significantly better performance, but more parts and more
expensive and it takes up more space. The same arguments that have been
used here recently to dump on a dual single brake system could be used to
dump on a twin OHC engine design vs. a pushrod engine design!

Kind of surprising to me to see arguments of this sort used by a bunch of
Alfisti, of all people!

(End of rant!) :-)

Regards, Greg
>
>- Jack

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