Re: Proportioning valve question
[Re: Ron Silva]
#421473
07/28/09 03:37 PM
07/28/09 03:37 PM
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Joined: Apr 2005
Posts: 1,880 USA
Ron Silva
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Joined: Apr 2005
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Smaller piston = higher brake fluid pressure. It's basic physics. You have the brake pedal, a lever (and leverage ratio), and a piston. Just think if the MC piston were 4" in diameter VS if it was 1/4" in diameter.
SRT DEMON ONE SEAT
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Re: Proportioning valve question
[Re: B G Racing]
#421477
07/28/09 04:23 PM
07/28/09 04:23 PM
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Joined: Aug 2004
Posts: 2,128 sweden
sshemi
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Quote:
The master cylinder volume is to displace the area of the of the pistons or wheel cylinders.A proportioning valve controls the pressure.A stock valve and a race valve do the same thing they open and close the passing orfice which controls the pressure,ie: putting your finger on a garden hose to increase the pressure.Small race calipers with small pucks can use a small MC(less area,less volume)large street calipers with large or multiple pucks need larger MC bores and resovires. By adjusting the size of the passing orfice(making it smaller) increases the pressure,usually in to increase and out to decrease on the race valves
So you sre saying that a propvalve is nothing more than a finger on the hose. Dont get me wrong here i want to learn this but wouldnt the finger keep the caliper pistons from returning and drag the rotors? Or is it a spring actuated valve of somekind?
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Re: Proportioning valve question
[Re: sshemi]
#421480
07/28/09 04:37 PM
07/28/09 04:37 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Quote:
The master cylinder volume is to displace the area of the of the pistons or wheel cylinders.A proportioning valve controls the pressure.A stock valve and a race valve do the same thing they open and close the passing orfice which controls the pressure,ie: putting your finger on a garden hose to increase the pressure.Small race calipers with small pucks can use a small MC(less area,less volume)large street calipers with large or multiple pucks need larger MC bores and resovires. By adjusting the size of the passing orfice(making it smaller) increases the pressure,usually in to increase and out to decrease on the race valves
So you sre saying that a propvalve is nothing more than a finger on the hose. Dont get me wrong here i want to learn this but wouldnt the finger keep the caliper pistons from returning and drag the rotors? Or is it a spring actuated valve of somekind?
It is like putting your finger over the hose BUT with the brakes its going into a closed area(line and caliper) SO the pressure will equalize on both sides of the valve after a giving period of time. All that valve is is a delay on the pressure... in hyd, the pressure will equalize
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Re: Proportioning valve question
[Re: Otherlane]
#421482
07/28/09 05:05 PM
07/28/09 05:05 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
So without a prop valve you will have the same pressure at all 4 corners? the same stopping power at all 4 corners?
Yes if the pistons in the master are the same, the only difference would be the size of the caliper pistons or wheel cylinder sizes... but if the master pistons are the same you have the same PRESSURE
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Re: Proportioning valve question
[Re: Otherlane]
#421483
07/28/09 05:08 PM
07/28/09 05:08 PM
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Joined: Apr 2005
Posts: 1,880 USA
Ron Silva
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Not necessarily the same stoping power. I have the same calipers at all 4 wheels but my front rotors are 10-1/2" and the rear rotors are 12+" so the rear will have more stopping power. Gee maybe that is why I don't have the need for a porportioning valve since I run big&little tires...........
SRT DEMON ONE SEAT
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Re: Proportioning valve question
[Re: Ron Silva]
#421484
07/28/09 05:13 PM
07/28/09 05:13 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Not necessarily the same stoping power. I have the same calipers at all 4 wheels but my front rotors are 10-1/2" and the rear rotors are 12+" so the rear will have more stopping power. Gee maybe that is why I don't have the need for a porportioning valve since I run big&little tires...........
Very true, the farther you get from the centerline the easier it is to stop the same mass
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Re: Proportioning valve question
[Re: Otherlane]
#421486
07/28/09 05:25 PM
07/28/09 05:25 PM
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Joined: Jan 2003
Posts: 32,394
Quicktree
I Win
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I Win
Joined: Jan 2003
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Quote:
With that being said would it be harder to do a burnout without a prop valve?
has nothing to do with it. only thing is there is not much front tire contact and if you don't get enough water on the slicks it will sometimes push the front tires.
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Re: Proportioning valve question
[Re: Otherlane]
#421487
07/28/09 05:38 PM
07/28/09 05:38 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
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Quote:
With that being said would it be harder to do a burnout without a prop valve?
You just have to hold the brake pedal a little longer for the pressure to get to the fronts(remember it will equalize)... most people including myself pump the pedal a few times and hold it then press the line lock
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Re: Proportioning valve question
[Re: MR_P_BODY]
#421488
07/28/09 05:52 PM
07/28/09 05:52 PM
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Joined: Jan 2003
Posts: 32,394
Quicktree
I Win
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I Win
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Quote:
Quote:
With that being said would it be harder to do a burnout without a prop valve?
You just have to hold the brake pedal a little longer for the pressure to get to the fronts(remember it will equalize
huh
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Re: Proportioning valve question
[Re: Quicktree]
#421489
07/28/09 06:20 PM
07/28/09 06:20 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Quote:
Quote:
With that being said would it be harder to do a burnout without a prop valve?
You just have to hold the brake pedal a little longer for the pressure to get to the fronts(remember it will equalize
huh
Tony.... if you have a prop valve in the fronts the pressure will be SLOW getting past the prop, then it will equalize after X period of time
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Re: Proportioning valve question
[Re: sshemi]
#421490
07/28/09 06:37 PM
07/28/09 06:37 PM
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Joined: Mar 2006
Posts: 9,910 Eighty Four, PA
B G Racing
master
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master
Joined: Mar 2006
Posts: 9,910
Eighty Four, PA
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Quote:
Quote:
The master cylinder volume is to displace the area of the of the pistons or wheel cylinders.A proportioning valve controls the pressure.A stock valve and a race valve do the same thing they open and close the passing orfice which controls the pressure,ie: putting your finger on a garden hose to increase the pressure.Small race calipers with small pucks can use a small MC(less area,less volume)large street calipers with large or multiple pucks need larger MC bores and resovires. By adjusting the size of the passing orfice(making it smaller) increases the pressure,usually in to increase and out to decrease on the race valves
So you sre saying that a propvalve is nothing more than a finger on the hose. Dont get me wrong here i want to learn this but wouldnt the finger keep the caliper pistons from returning and drag the rotors? Or is it a spring actuated valve of somekind?
Your not comprehending this at all,the pressure is only when the piston is depressed in the master cylinder which inturn pushes the fluid through the system pushing the pucks and applying the brakes,when the pedal is released so is the pressure,simply theory of hydraulics pressure applied through the pedal ratio,applied through mc bore/stroke,controlling a given volume at a given pressure.Change in pressure can be regulated by the size of orfice it passes through.The small orfice holds back the volume(under pressure) and the orfice creates the additional pressure.ie: a nozzle on a fire hose or pressure washer.Sorry I can't explain it any simpler,hope it helps you understand.Another example would be a diesal fuel injection system where as a pump generally pumps fuel at 45psi to the injector nozzle the nozzle orfice releases fuel at 1800psi.
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