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Re: Hydraulic pressures

To: Bob Palmer <rpalmer@ames.ucsd.edu>, tigers@autox.team.net
Subject: Re: Hydraulic pressures
From: ritchie@mcn.org (Armand & Lorie Ritchie)
Date: Sun, 24 Jan 1999 19:03:39 -0800 (PST)
>Tom,
>
>Thanks for pointing out (again) the importance of the mechanical part of
>the system. BTW, probably only an engineer would call 4.47 "approximately".
>Being a physicist, I'll just round that off to 4.5 thank you. Also, wrt
>your statement: "He could have also reduced the distance between the pedal
>pivot and the connection to the master cylinder with the same result, as
>long as the mechanical components stayed within  appropriate operating
>ranges." I believe you meant "increased the distance" so as to reduce the
>mechanical advantage.
>
>Now, I suppose it would be helpful if we could come up with an easy way to
>remember which way the mechanical advantage works in a hydraulic system. It
>seems pretty obvious with a mechanical lever. The longer the lever arm, the
>farther we have to push, but the easier it is. With the master/slave ratio
>its still the farther we have to push, the easier it is, and a smaller
>master bore requires more motion to accomplish the same motion of the
>slave. So smaller master bore equates to longer lever arm. Now personally,
>I think in terms of force times area, which has to be equal at each end,
>but maybe that doesn't work for everyone. Or maybe we could think of the
>master cylinder as another foot pushing back and the bigger that foot, the
>harder he has to push. Anything clicking here Armand?
>
>I think Armand's suggestion of changing the master cylinder, although to a
>slightly smaller bore, might be a good alternative to a booster. Or, as Tom
>alludes, you could increase the mechanical ratio at the pedal. The downside
>to these ideas is that you increase the pedal travel required, so you can
>only go so far with this approach; but maybe enough to make it acceptable
>(e.g., 6:1)
>
>Have a nice evening,
>
>Bob


Hi Bob, I think I'm finally getting it, Italians are dense you know.  I was
wondering if it might just be the way the brake master cyl. is constructed,
that causes problems when we remove the booster.  On my series I alpine the
brake master cyl. was a little different in it's internal design.  It was
much simpler almost like the clutch master.    The brakes worked great on
that car and there was no booster.  Just a thought.

 Did you take your car out today? I almost did but got sidetracked with
"Yard Work"  It was a nice day though, I think I got a little sunburned.
Or was that embarrassed. Regards Armand

ritchie@mcn.org
Armand & Lorie Ritchie



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