Wally,

I've been through your spreadsheet and I understand where all the numbers
come from, having deciphered all your divisors. However, I don't
understand the logic of the last two columns, I and J. The best I can
figure, you're saying that there are 4 different input rods available
(0.545" to 0.781" in diameter). And that the pedal pressure required to
produce output is dependent upon the area of the selected input rod (and
the mechanical advantage in the pedal)? Huh! Shows how much I know about
Hydroboost! I had always figured that the pedal pressure merely overcame a
spring load, independent of the PS pump pressure. Have I been that wrong
all this time?

I guess the reason for my confusion is my past experience with a Chevy P-30
chassis motorhome which had what I thought were a variant on Hydroboost
brakes. That coach had a really weird feeling brake pedal and the owner's
manual recognized that. It had a statement to the effect that "...it's OK
if the pedal goes all the way to the floor, you're still getting maximum
braking...". And I had a panic incident that verified that statement with
extremely good braking. Admittedly my current Hydroboost feels nothing
like that one did.

Ken
​ Confused​
H.


On Sat, May 27, 2017 at 7:05 PM, Wally Anderson
wrote:

> I've made a spreadsheet on Google sheets to show brake pressures available
> from hydroboost conversions of factory vacuum assist brakes specific to our
> GMC's. It shows pedal force, effects of different master cylinders and
> variable pump pressure.
> https://docs.google.com/spreadsheets/d/1za2yNDR77iZDuC_
> mNj9syVgZTOP1HXGSpbT4vrS5xIw/edit?usp=sharing
> https://docs.google.com/spreadsheets/d/1za2yNDR77iZDuC_
> mNj9syVgZTOP1HXGSpbT4vrS5xIw/edit?usp=sharing
> --
> Wally Anderson
> Omaha NE
> 75 Glenbrook
> Megasquirt III injection
> Bob Stone hydroBOOOOST
> Manny reaction arm system
> Branscombe Kelsey Hayes park brake
> http://wallyandsue.blogspot.com/
>
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