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ideas are dancing in my head for the pedal box


instructorbill

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It has been said that the pushrod setup that drives the booster for a standard 2002 may introduce "vagueness" through linkage.

In my quest for space around the pedal box area, I've discovered that I've got very little room to mount a booser directly to the back of the pedal box unless I relocate the foreward wall of the pedal box aft of its current location.

Currently, I have 5 inches plus a hair... not a bunch of room really.

I've looked at some of the high volume masters available from Willwood. I can't tell, but it seems that their masters only have a single line out. I'd prefer at least two (though I still need to do the math on master piston volume vs. caliper volume, pedal pressure, pedal ratio yada yadda yaddda)

I'm doing all of my homework

http://www.stoptech.com/tech_info/PedalSetup-DualMaster-Guide.pdf

Background-- I really need a bunch of space high in the engine compartment where the booster/master once was, I've totally removed the mount for the driver's side including the steering box mount and my steering rack is comfortably settled into its new home.

Proposal-- Since I have the room down low, I am thinking about moving the mount that formerly used to hold the pushrod linkage for the booster down several inches, appropriately shorten the linkage, use the stock brake pushrod pivot, remove the booster and then mount two master cylinders (with remote reservoir) and a ballance bar.

I'm away from the car until tomorrow, otherwise I'd take a few pics of what I'm talking about. the major hurdle will be clearing the steering linkage now.

Anybody have any input? Will I have a "vague" boosterless setup due to the linkage? Crap, I may not even use the idea. But I'd though it best to bounce it off of you guys.

Make it different... or just do it differently

Bill in Petaluma, CA

1969 1600 supercharged m20 in progress

1970 2002 RIP -- crashed then quartered

1971 2002 M20/02 RIP -- nothing but pieces now

1972 2002 gone, but not missed POS

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Remember that the higher volume a master pushes, the harder the pedal will be to push to get the same braking force. I would guess that if I were going booster-less, I'd go with pushing less volume to get more hydraulic advantage.

John

Fresh squeezed horseshoes and hand grenades

1665778

 

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Do a search for the markmac alpina 2002 pedalbox that has a master cylinder mounted directly to the pedal box. Leaves you all kinds of room where the MC and Booster used to be. I know he posted pictures of it. As a matter of fact if you look in his latest post, the first picture shows it mounted way down on the pedal box. You can almost see all the way down to the pavement in that shot.

-=Scott=-

My Short Bus

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1971 2002 - "William Grover-Williams" - Track/Weekend Car VIN 2579197

1998 740iL E38 - "Blau" - Daily Driver

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I understand with fixed force at the pedal say 40lbs with a pedal ratio of say 6:1 onto a small master cylinder of say 1sq inch area I will be applying about 240 lbs/sq inch to the master

Double the area with two master cylinders of the same size in the example above with a bias bar and I've got 120lbs per sq inch on each master for a total of 240lbs/sq inch

When we're talking volume (disregarding pedal pressure), move the top example one inch versus the bottom example one inch... twice the volume on the bottom versus the top Yes?

Make it different... or just do it differently

Bill in Petaluma, CA

1969 1600 supercharged m20 in progress

1970 2002 RIP -- crashed then quartered

1971 2002 M20/02 RIP -- nothing but pieces now

1972 2002 gone, but not missed POS

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The way I understand it is that it's like a seesaw. Move the fulcrum point for mechanical advantage. Push a little into a large volume makes little movement but lots of force. Move a lot into a small volume makes it move a lot with little force. Big MC volume into the same size calipers means a harder pedal pressure to get the same braking force.

If I was going that no booster route, I would think smaller MC bore.

John

Fresh squeezed horseshoes and hand grenades

1665778

 

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yes... smaller bore with more travel will equal same displacement in the calipers, but does high displacement mean larger bore? I'll have to look at the specs on Willwood's site

Make it different... or just do it differently

Bill in Petaluma, CA

1969 1600 supercharged m20 in progress

1970 2002 RIP -- crashed then quartered

1971 2002 M20/02 RIP -- nothing but pieces now

1972 2002 gone, but not missed POS

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Hey Bill,

I saw your post a few pages back- I haven't gotten the lower rig to work

yet. Right now, the dual masters (I'm split front/rear) are where the

booster used to be, and that's no good for 45's. So...

There seems to be room for 2 standard- frame Tiltons at the pedal box if

the clutch master isn't there. I'm planning on spacing them evenly

about the brake pedal (moving the pivot left or right if needed, then bending

the arm) with the adjuster buried into the pedal arm.

Then there's no room in the inn for the clutch. But if it moves forward

about 4" and up an inch or 2, there's a spot- so I'm planning on remoting

the clutch master. It takes a LOT less stress than the brake masters.

Actuation will be less linear- but it's the clutch, which in my car is

usually just a switch anyway...

The clutch master's just a 3/4" bore cylinder, so I figure I'll just use one

from Girling that I have sitting around...

The other salient bit I can add is that my front master is, IIRC, 3/4",

and it acts on all four front pots of the tii calipers that I use. The effective

pedal ratio is 6:1, and pedal pressure is, in my estimation, 'quite high'.

Great for a race car, probably a bit much for a street car.

More as I get to it- probably in the next month or 2...

Hope it helps,

t

post-611-1366759444614_thumb.jpg

"I learn best through painful, expensive experience, so I feel like I've gotten my money's worth." MattL

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Displacement's just bore x stroke, like an engine, so

a 'high displacement' brake cylinder is usually a 'stroker!'

The bore's critical to ratios, so must always be specified.

As to getting a dual- circuit master in there, I can't see how there's

the length- you'd have better luck doing it race- car style side- by- side

as the parts are light and available, if not cheap...

again, I'll post when I do anything interesting...

t

"I learn best through painful, expensive experience, so I feel like I've gotten my money's worth." MattL

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I was thinking of a setup similar to the one that Toby had pictured, but with the standard linkage still attached, but I do like the idea of the remoted clutch.

If I'm picturing this correctly, I think the remote would work if the clutch pedal were in the same fashion as the stock brake pedal with a pushrod that moves the clutch master up and then transfers the energy laterally and foreward to actuate the piston

Then, the dual master brake cylinders would be mounted on a plate on the back of the pedal box, with the bias adjuster inside the pedal box

Make it different... or just do it differently

Bill in Petaluma, CA

1969 1600 supercharged m20 in progress

1970 2002 RIP -- crashed then quartered

1971 2002 M20/02 RIP -- nothing but pieces now

1972 2002 gone, but not missed POS

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Naive notion. My own thoughts toward these ends were to mount the dual cylinders over/under at the pedal box still leaving room for the clutch. Seems like it would fit? No?

Not bad! But then there's a motion problem- you'll have to

figure out how to pivot vertically between the two. So some form of separate

linkage. I was 'stealing' Gordon Jones' idea of putting the balance bar

in the pedal itself, as it will act as the pivot in the same plane as the

pedal pivot. oooo, I just gave myself a headache, but you know what I

mean...

t

"I learn best through painful, expensive experience, so I feel like I've gotten my money's worth." MattL

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Naive notion. My own thoughts toward these ends were to mount the dual cylinders over/under at the pedal box still leaving room for the clutch. Seems like it would fit? No?

Not bad! But then there's a motion problem- you'll have to

figure out how to pivot vertically between the two. So some form of separate

linkage. I was 'stealing' Gordon Jones' idea of putting the balance bar

in the pedal itself, as it will act as the pivot in the same plane as the

pedal pivot. oooo, I just gave myself a headache, but you know what I

mean...

t

How about attaching a clevis or rod end to the pedal arm and then run that to a vertically mounted balance bar? I thought it might work but gotten even so far as to look and measure.

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