Proportioning Valve thread - theory and discussion
04-20-2012, 12:25 PM
#26
Re: Proportioning Valve thread - theory and discussion
Good observation. There are some twin port valves available, but to run a single one you would have to re route the lines so that one MC port feeds through a T the front brakes, and one feeds through the valve and into a T to the rear brakes. Obviously this would necessitate ABS removal, but if you've gone for big changes over stock this won't be working optimally anyway and may well hinder performance.
The twin ports are more expensive but factor in the faffing about with lines then it's probably the better option
The twin ports are more expensive but factor in the faffing about with lines then it's probably the better option
04-20-2012, 12:29 PM
#27
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Re: Proportioning Valve thread - theory and discussion
It wouldn't require ABS removal. Since ABS uses a 4-port valve, you can just replace it with two 2-port valves and your good to go. Get fancy with the lines and extensions and you can put those adjustable ***** inside the car at arms reach. Just pray nobody ever messes with them.
04-20-2012, 12:37 PM
#28
Re: Proportioning Valve thread - theory and discussion
Haha, a friend actually had this happen after he bought a new car with one fitted, had another chap in the passenger seat who said exactly that whilst twisting it all the way round and back. The driver had knew what it was but not a clue what setting it was on or which way to adjust it. He described the first few stops as "**** twitching".
04-20-2012, 09:45 PM
#30
Honda-Tech Member
Re: Proportioning Valve thread - theory and discussion
Is the weight distribution really that much different then a gsr which uses 46210-s04-852?
04-21-2012, 08:42 AM
#31
Re: Proportioning Valve thread - theory and discussion
I would certainly think so. An AWD SUV has a greater percentage of it's weight over the back than a FWD hatchback (Integra). The 2WD CRV's use a different valve than the 4WD as well....46210-S10-972.
04-23-2012, 02:38 AM
#32
Re: Proportioning Valve thread - theory and discussion
BrakeExpert, if you are reading this, would you have any hesitations about fitting a disc brake prop valve to your Civic with NSX rear brakes?
04-25-2012, 07:29 PM
#33
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Re: Proportioning Valve thread - theory and discussion
The issue is that not only is the weight distribution important in a static situation, it is also important to think about the distribution while braking. All of our cars are (hopefully) stiffer than stock, so they have less weight transfer to the front than a stock vehicle. Without doing anything else, our cars can actually use more rear brake bias than a stock one.
04-25-2012, 09:24 PM
#34
Re: Proportioning Valve thread - theory and discussion
Please realize that I am new to this conversation, but I hope you don't mind if I comment.
The issue is that not only is the weight distribution important in a static situation, it is also important to think about the distribution while braking. All of our cars are (hopefully) stiffer than stock, so they have less weight transfer to the front than a stock vehicle. Without doing anything else, our cars can actually use more rear brake bias than a stock one.
The issue is that not only is the weight distribution important in a static situation, it is also important to think about the distribution while braking. All of our cars are (hopefully) stiffer than stock, so they have less weight transfer to the front than a stock vehicle. Without doing anything else, our cars can actually use more rear brake bias than a stock one.
If you check this article, it describes all the factors that effect bias (and how):
http://stoptech.com/technical-suppor...alance-matters
04-26-2012, 12:24 AM
#35
Re: Proportioning Valve thread - theory and discussion
Stiffer suspension does not change load transfer, only the sprung chassis' reaction to it. 
For anyone that is interested, I can calculate the dynamic threshold bias of any chassis and combination of parts you could want, relative to a baseline setup. Literally any parameter that matters can be altered and assesed for bias, stopping distance, pedal force and temperature. All are subject to some assumptions (tyres, boosters, thermodynamic anamolies etc) but I think I've done a reasonable job of incorporating all significant factors and the results are a good indication of how different upgrades will effect the overall system.
If anyone has any questions, fire away.
For anyone that is interested, I can calculate the dynamic threshold bias of any chassis and combination of parts you could want, relative to a baseline setup. Literally any parameter that matters can be altered and assesed for bias, stopping distance, pedal force and temperature. All are subject to some assumptions (tyres, boosters, thermodynamic anamolies etc) but I think I've done a reasonable job of incorporating all significant factors and the results are a good indication of how different upgrades will effect the overall system.
If anyone has any questions, fire away.
04-26-2012, 12:45 AM
#36
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Re: Proportioning Valve thread - theory and discussion
I do not believe that it has been covered yet so can someone please explain what the stamped numbers on the factory Honda prop. valves signify?
I know most people go for the 40/40 when doing a rear disc swap, but I am curious as to why?
Im sure it stands for distribution of some sort, but is it a percentage??
I have seen a few different ones like 30/40, 20/40..etc
I know most people go for the 40/40 when doing a rear disc swap, but I am curious as to why?
Im sure it stands for distribution of some sort, but is it a percentage??
I have seen a few different ones like 30/40, 20/40..etc
04-26-2012, 05:21 AM
#38
Re: Proportioning Valve thread - theory and discussion
Komodo is correct. It's just a manufacturing ID number. The number expressed as a ratio, as Mr. Winky has done above (ie 40/40), is a common mistake. It's also probably the source of the confusion. The stamps say 4040 not 40/40. It is not a ratio, just a 4 digit ID.
04-26-2012, 08:50 AM
#39
Re: Proportioning Valve thread - theory and discussion
Komodo:
My EK has had about 6 different NSX brake types, like the bigger NSX fronts and smaller NSX rears, on the factory prop valve meant for drums. With performance tires, even in the rain, I've not had the rears lockup first. Switching to a 99 Civic Si prop valve isn't gonna change this.
When I had 4 wheel NSX type-R brakes, the rears were overbiased. No Honda prop valve is going to correct this, you'd need an aftermarket one, the rears WILL lockup first with that setup because the rear brakes are expecting about twice the weight.
Or were you asking me to put one on my car and test it out? Cause I don't have one anymore. Refer to the operation of a rear-drum type prop valve (its called a combination valve)
My EK has had about 6 different NSX brake types, like the bigger NSX fronts and smaller NSX rears, on the factory prop valve meant for drums. With performance tires, even in the rain, I've not had the rears lockup first. Switching to a 99 Civic Si prop valve isn't gonna change this.
When I had 4 wheel NSX type-R brakes, the rears were overbiased. No Honda prop valve is going to correct this, you'd need an aftermarket one, the rears WILL lockup first with that setup because the rear brakes are expecting about twice the weight.
Or were you asking me to put one on my car and test it out? Cause I don't have one anymore. Refer to the operation of a rear-drum type prop valve (its called a combination valve)
04-26-2012, 01:14 PM
#40
Re: Proportioning Valve thread - theory and discussion
Komodo:
My EK has had about 6 different NSX brake types, like the bigger NSX fronts and smaller NSX rears, on the factory prop valve meant for drums. With performance tires, even in the rain, I've not had the rears lockup first. Switching to a 99 Civic Si prop valve isn't gonna change this.
My EK has had about 6 different NSX brake types, like the bigger NSX fronts and smaller NSX rears, on the factory prop valve meant for drums. With performance tires, even in the rain, I've not had the rears lockup first. Switching to a 99 Civic Si prop valve isn't gonna change this.
Yes I was asking if you would have any qualms about fitting a prop valve for a full disc brake model to your car. I notice you mention the operation of the valve in your article, but only in so much as it's function of sending more fluid initially to take up slack in the system. What are your thoughts on how the valve actually regulates the pressure going to the rear brakes?
Last edited by Kozy.; 04-26-2012 at 02:13 PM.
04-26-2012, 02:14 PM
#41
Re: Proportioning Valve thread - theory and discussion
Lets take a different scenario and forget drum brakes all together.
Consider a DC2R with a high performance four wheel disc brake system and a 62% front weight distribution, proportioned such that at maximum deceleration where the front tyres are 100% saturated (torque/grip) and the rears are 90% saturated. This is a 10% front bias, noted by the chaps at Stoptech of being a fairly typical performance production car bias.
On this car, would you (or indeed have you) fit (fitted) a set of NSX front and rear brakes? How do you expect brakes designed for a car with a 58% rear weight distribution will perform on a car with only a 38% rear distribution? Bear in mind that the NA2 front brakes are actually weaker than the stock DC2 fronts (to the tune of around 4%), and the rear NA1 calipers are around 70% stronger.
With the same prop valve, is it going to be safe?
Consider a DC2R with a high performance four wheel disc brake system and a 62% front weight distribution, proportioned such that at maximum deceleration where the front tyres are 100% saturated (torque/grip) and the rears are 90% saturated. This is a 10% front bias, noted by the chaps at Stoptech of being a fairly typical performance production car bias.
On this car, would you (or indeed have you) fit (fitted) a set of NSX front and rear brakes? How do you expect brakes designed for a car with a 58% rear weight distribution will perform on a car with only a 38% rear distribution? Bear in mind that the NA2 front brakes are actually weaker than the stock DC2 fronts (to the tune of around 4%), and the rear NA1 calipers are around 70% stronger.
With the same prop valve, is it going to be safe?
04-26-2012, 06:03 PM
#42
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Re: Proportioning Valve thread - theory and discussion
Here are some interesting facts....
The UK EK9 prop valve is found on 01-02 Accord EX's. It is also a 4-port ABS valve and cannot be used on the US Si. http://www.hondapartsnow.com/genuine/honda~valve~assy~46210-S10-862.html
The UK EK9 prop valve is found on 01-02 Accord EX's. It is also a 4-port ABS valve and cannot be used on the US Si. http://www.hondapartsnow.com/genuine/honda~valve~assy~46210-S10-862.html
They share the same front brake setup, which seems to dictate which prop valve gets used more often than not. Also ABS prop valves are just a dummy valve anyway I believe.
04-26-2012, 09:12 PM
#43
Re: Proportioning Valve thread - theory and discussion
The 4-channel ABS on the EK and later DC and more did have an external prop valve with just 4 ports.
Once Honda added EBD to their ABS system (03 Si & RSX), they did away with the prop valve again and replaced with a dummy joint.
04-27-2012, 12:15 AM
#44
Re: Proportioning Valve thread - theory and discussion
On the older stand-alone 3-channel abs (DA, EG & Early DC), proportioning was done in the ABS modulator. The thing where the prop valve would go was just a dummy joint.
Once Honda added EBD to their ABS system (03 Si & RSX), they did away with the prop valve again and replaced with a dummy joint.
Once Honda added EBD to their ABS system (03 Si & RSX), they did away with the prop valve again and replaced with a dummy joint.
04-27-2012, 01:05 PM
#45
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Re: Proportioning Valve thread - theory and discussion
I will ask this question in here, bc I never got the correct answer in my other thread:
With Na1 NSX front dual piston calipers and factory dx rear drum on 92 hatchback, what is the "proper" factory prop. valve I should be using? I was given all kinds of mixed opinions and answers in my last thread.
With Na1 NSX front dual piston calipers and factory dx rear drum on 92 hatchback, what is the "proper" factory prop. valve I should be using? I was given all kinds of mixed opinions and answers in my last thread.
04-27-2012, 01:27 PM
#47
Re: Proportioning Valve thread - theory and discussion
Wait, if there was no prop valve then those older systems were simply activating the ABS to control rear wheel lock up? That sounds like basic EBD to me, which they then did away with for the EK in favour of a proper prop valve, to then return with a more refined system labelled as 'EBD' in 1997?
Originally Posted by Helms 92 Civic
PCV (Proportioning Control Valve) Function
In the modulator for the rear wheels, the diameters of the piston and the slide-piston are distinctly different. This provides a PCV (Proportioning Control Valve) function to prevent the rear wheels from locking during an emergency stop.
In the modulator for the rear wheels, the diameters of the piston and the slide-piston are distinctly different. This provides a PCV (Proportioning Control Valve) function to prevent the rear wheels from locking during an emergency stop.
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