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so if you dont change your prop valve with your therory then ur rear disc would brake before the front if you did a rear disc convert.
unless the prop valve is an automatic unit like u say.
but dont alot of people have problems with rear lock up with out swaping out prop valve
no, peope do NOT have problems with rear brake lockup. Your front brakes will ALWAYS lock up before the front unless you have shot front brakes.
What I have stated in my post is that what people say is a MYTH and does not happen. By not changine the valve, you will not have any adverse effect on braking ability and it will actually perform identically to the systems equipped with 40/40 valves.
30/30 i believe is on my 92 dx hatch
40/30 which was on my 92 si hatch with rear disc or if i used a 40/40 from a teg
if i swaped them what would happen
trying to grasp the concept here
so a civic with drum brakes only has a different prop valve to make up for the difference in distance the show need to move to the drum one pressure hits its all the same???
This is interesting. If someone can prove that the original prop valve does the same thing I would be willing to believe them. I will keep an eye on this thread but good work so far .
uhh. my proportioning valve says 40/60 and i have ctr 5 lug with the itr MC and booster. i never had the rears lock up before the front. and i run this car in the mountain weekly. i have a civic hatch dx.
i was always confused as to why people online say the rear would lock up first.
but then again lots of peolple said the civic ps line wont work with my h22 pump. but i win
I have 94+ Integra front and rear brakes on a 92 Civic Cx. Upgraded to 15/16" MC made for 91 Civic Sedan Ex that came with equivalent size rotors. Did not change prop valve bc I had the valve that was apparently for ABS Integra (off a LS) and it didn't align with the brake hardline in the Civic.
I haven't noticed any braking problems and the car stops very well. I've read however that the correct prop valve for this swap is out of a 94+ Integra RS (which was non-abs like my Civic).
I've always wondered if the prop valve would affect pedal feel, this is something that has bothered me about my brakes. I think that they might feel a little different an with a little less travel w/ the valve.
= Interesting comment about the different prop valves. I've always read that the 40/40 was appropriate for my brake set up and never really considering the 30/30 30/40 and other alternatives.
Well - interested in topic but not going to change my prop valve until next time I do rotors and pads.. Seem to work well enough for now.
to the original poster, you did a good job telling what a proportioning valve does but have you been able to prove the differneces on why cars with rear disk have a different prop valve than the exact same car with rear disk?
the theory i am toying with is this. it is true in a hydraulic system pressure is equal through out, but what the prop valve does is "create" what seems to be equal pressure through but allowing more pressure to the fronts.
i hope this makes sense. if not i will try to explain it more
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote »</TD></TR><TR><TD CLASS="quote">if that becomes too much of a pain i got a teeny program off the net called Capture that takes a photo of the whole screen, so if your lookin at a movie or pdf, itll save that screenshot to a jpg or bmp. </TD></TR></TABLE>
You don't need a program to do that, it's built into windows. That's probably a spyware program.
Why convert it to jpg? pdf is also a common internet file type that none of us will have a problem viewing.
I will agree that the term "proportioning valve" is incorrect for this particular Honda part, and that the information and rumors about this part are all wrong here on Honda Tech. I will also agree that if you change the rear drums for discs and keep the stock front discs, you shouldn't swap the "proportioning valve". HOWEVER, if you swap ALL FOUR brakes and keep your stock "proportioning vale", you will have problems with the brakes locking up any time you hit them hard.
Also, changes to the spring rate, struts, front/rear weight balance, and ride height will change the optimum front to rear disc brake proportioning. Anyone who has modified their suspension and brakes will benefit from an adjustment made to the proportioning of the front to rear brakes.
I have an EG that came with rear drums. I put upwards of 20,000 miles on the car a year according to my insurance company. About eight months after buying the car, I lowered the car 1.5 inches on Tokico "type R" coilovers. The braking improved a bit probably because the car doesn't dip forward as much under hard braking. About six months later I swapped LS integra rear discs and kept everything else stock, replacing pads and rotors on all four corners. Braking actually improved noticeably, which is surprising because drums have more stopping power in street driving than discs, although they do not perform well under intense use because they don't disperse heat as quickly as discs. I'm guessing that the there is a similarity between the optimum brake "proportioning" (or whatever the function of that part is) on the stock-disc/drum stock-suspension setup as the optimum brake "proportioning" of a lowered-stiffened-suspension stock-front-discs swapped rear discs setup.
Seeking even better braking, I swapped the front discs with LS Integra discs, replacing the rotors and pads with the same brand as the rear, and installing braided lines on all four corners. I immediately started having problems locking up the brakes in situations where I had to hit them hard. A few weeks later I got a proportioning valve from a Del Sol that had rear disc brakes, retaining the stock booster, and I swapped the factory master cylinder for a 15/16 '91 Civic master cylinder*. There was a noticeable improvement in braking, you have to be at a higher speed to lock up the brakes, and it felt as if something was pulling from behind during hard braking and the car seemed to dip forward less during hard braking. This turned me on to the idea that I could get even better braking by tuning the front to rear proportioning.
The next thing I did was replace the Del Sol prop valve with a Wilwood adjustable **** prop valve. The front lines are T'd together essentially sending max pressure to the front, and the adjustable **** is installed in the rear lines. Then a friend (who happens to be an educated tuner) and I took a video camera out to a gravel parking lot and adjusted the brakes until the front and rear locked up at the same time. Then we made some fine adjustments to soften the rear proportioning until we determined that the front should be locking up a split second before the rear, that way when I'm at the limit of the brakes and lock them up, I get safe understeer instead of spinning out. (All this was done for an article for Honda Tuning magazine that never happened. Honda Tuning apparently couldn't establish some marketing **** with Wilwood.)
Braking is ******* amazing. The brakes are perfectly optimized for my setup, and the only limitation is the compound on the tires. You can't lock up the brakes unless you are being stupid and really trying. In fact, in trying to test the limitation of the brake system locking up at high speeds, we actually broke an axle! That sucked, putting the test to an early end, but luckily we found a spare axle in the dyno shop.
*Master cylinder only affects pedal feel for the types of brake modifications we are doing. No significant improvement to actual braking distance.
I will agree that the term "proportioning valve" is incorrect for this particular Honda part, and that the information and rumors about this part are all wrong here on Honda Tech. I will also agree that if you change the rear drums for discs and keep the stock front discs, you shouldn't swap the "proportioning valve". HOWEVER, if you swap ALL FOUR brakes and keep your stock "proportioning vale", you will have problems with the brakes locking up any time you hit them hard.
Also, changes to the spring rate, struts, front/rear weight balance, and ride height will change the optimum front to rear disc brake proportioning. Anyone who has modified their suspension and brakes will benefit from an adjustment made to the proportioning of the front to rear brakes.
I have an EG that came with rear drums. I put upwards of 20,000 miles on the car a year according to my insurance company. About eight months after buying the car, I lowered the car 1.5 inches on Tokico "type R" coilovers. The braking improved a bit probably because the car doesn't dip forward as much under hard braking. About six months later I swapped LS integra rear discs and kept everything else stock, replacing pads and rotors on all four corners. Braking actually improved noticeably, which is surprising because drums have more stopping power in street driving than discs, although they do not perform well under intense use because they don't disperse heat as quickly as discs. I'm guessing that the there is a similarity between the optimum brake "proportioning" (or whatever the function of that part is) on the stock-disc/drum stock-suspension setup as the optimum brake "proportioning" of a lowered-stiffened-suspension stock-front-discs swapped rear discs setup.
Seeking even better braking, I swapped the front discs with LS Integra discs, replacing the rotors and pads with the same brand as the rear, and installing braided lines on all four corners. I immediately started having problems locking up the brakes in situations where I had to hit them hard. A few weeks later I got a proportioning valve from a Del Sol that had rear disc brakes, retaining the stock booster, and I swapped the factory master cylinder for a 15/16 '91 Civic master cylinder*. There was a noticeable improvement in braking, you have to be at a higher speed to lock up the brakes, and it felt as if something was pulling from behind during hard braking and the car seemed to dip forward less during hard braking. This turned me on to the idea that I could get even better braking by tuning the front to rear proportioning.
The next thing I did was replace the Del Sol prop valve with a Wilwood adjustable **** prop valve. The front lines are T'd together essentially sending max pressure to the front, and the adjustable **** is installed in the rear lines. Then a friend (who happens to be an educated tuner) and I took a video camera out to a gravel parking lot and adjusted the brakes until the front and rear locked up at the same time. Then we made some fine adjustments to soften the rear proportioning until we determined that the front should be locking up a split second before the rear, that way when I'm at the limit of the brakes and lock them up, I get safe understeer instead of spinning out. (All this was done for an article for Honda Tuning magazine that never happened. Honda Tuning apparently couldn't establish some marketing **** with Wilwood.)
Braking is ******* amazing. The brakes are perfectly optimized for my setup, and the only limitation is the compound on the tires. You can't lock up the brakes unless you are being stupid and really trying. In fact, in trying to test the limitation of the brake system locking up at high speeds, we actually broke an axle! That sucked, putting the test to an early end, but luckily we found a spare axle in the dyno shop.
*Master cylinder only affects pedal feel for the types of brake modifications we are doing. No significant improvement to actual braking distance.
Not true, you forgot to mention brake friction coefficient has a lot to do with brake bias. Once you change out the brake pads to different compounds your effecting your brake bias. With my car I've tried multiple front and rear brake pad compound to get the correct bias. If I were to change nothing else but my front pads to a lower friction coefficient compound I would have rear lock up issues.
You say when you changed your front rotors I'm assuming you went to a larger caliper and rotor size? Where were your lock up issues, front or back? My guess is that you put better pads up front and with the stiffer braided lines that the brakes became more sensitive and thus required more control on your end not to just stab them and expect not to lock up.
The wilwood adjustable porp valve is a nice mod! I'm glad you like it, but just because you had some brake isssues that you were unsure of the cause does nothing to prove the OEM porp valve was the reason.
I understand why you feel this way but if you could have the first hand experience with the process I went through, you would agree with me.
You wont catch me using phrases like "brake friction coefficient" because that doesn't mean anything to the layman. I'm only talking about real world experience. What actually occurs is more important than what the theory predicts should occur. Sometimes the theory only works in the lab, sometimes the theory is being mis-applied. The complete function of the part we call "prop valve" on our Hondas isn't clear. I have no doubt that the information you presented is correct because I've read it myself from multiple sources, however it could very well be correct for a different part and not this particular Honda part we're calling "prop valve".
I realize my post was very long so I'll try to clear it up. I went from a stock Civic DX, to stock DX fronts and LS rear knuckles with DX prop valve (no lock up problems), to LS f/r knuckles with DX prop valve (major lock up problems), to LS f/r knuckles with a Del Sol (w/rear disc brakes) prop valve (no lockup problems), and finally to LS f/r knuckles with an adjustable prop valve (tires are the limiting factor, not the brakes). LS knuckles f/r. OEM LS calipers f/r, OEM sized Brembo blanks f/r, PBR pads f/r, braided lines f/r. Since the original install, I have replaced the pads and resurfaced the rotors on all corners all at once.
The only time I had a mismatch from the factory intended brake bias was when I had DX front brakes and LS rear brakes. Even though there was brembos f/r, PBR pads f/r, the DX calipers, rotor diameter, and pad size on the front were smaller than what the factory intended to go with the LS rear pads and rotors. But this actually proves slightly beneficial because the optimum brake bias on this setup (taking into account changes made to suspension and weight) is closer to what you get with the stock DX prop valve than what you would get if you swapped to a prop valve from a car with rear discs.
I understand why you might think that my lockup problems could have been caused by the braided lines, but after the swap from rubber lines I felt like it was EASIER to be more consistent on the pedal than before. It removed the freeplay so the brakes began to respond to my foot almost instantly. Changing from one prop valve to another immediately solved the problem. If it was caused by my inexperience with the new braided lines, this would not have been the case.
I'm not saying I'm a great driver, but I have found myself in an emergency braking situation almost every day for the past 6 years (I used to deliver pizza during daddy traffic (fast moving tightly packed traffic)). I wouldn't mind having ABS. But with this setup and a careful foot, I may not even need it.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote »</TD></TR><TR><TD CLASS="quote">You say when you changed your front rotors I'm assuming you went to a larger caliper and rotor size?</TD></TR></TABLE>
No I meant that I replaced the junkyard rotors and pads with brand new aftermarket OEM replacement pads and rotors. I had all four calipers rebuilt 6-8 months after I finally swapped LS knuckles on the front to match the rear LS knuckles.
It's hard to remember now if the lock up problem was with the front or rear, since most of the situations I got into were straight line braking situations, not turns. And I've done so much experimentation with different setups and with the adj prop valve between then and now that I don't remember which end had the problem.
this is a fun discussion. im not going to argue with anyone but i have my own general theories about at least the numbering convention of honda prop valves. i will say this, i think wheel base and vehicle weight has something to do with it as well. i also happen to know the stock brakes have a rear lockup prevention system that kicks in at a certain pressure/time delay that will release the rear brake pressure when you slam on the brakes. im sure that has something to do with the design of the prop valve.
anyway, ive accumulated a spreadsheet of brake parts as it relates mostly to EF stuff. most later models dont swap so easily into CRX's, so i havent bothered to record any of it. take a look anyway.
and whats with adding a "/" in between the first and last pair of digits? its just 4040, or 3540, not 40/40. we're not talking eye charts and prescriptions...
Re: Proportioning valves explained and why it is not necessary to change them (junkyard_turbO)
It depends on your setup. Are you only putting on rear disc brakes (keep your stock prop valve), or are you swapping all four corners (get a prop valve with rear disc brakes)?
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote »</TD></TR><TR><TD CLASS="quote">wow you couldn't be more wrong</TD></TR></TABLE>
Nice argument. How about nobody posts **** unless they have personal experience. Everyone that's been in the situation over the years has come on these boards and said "why do my brakes suck after the conversion?" And then everyone on HT says "get the prop valve".
did you happen to notice that he was talking about a Mechanical proportiong valve that is found on dual master cylinder setups......it was not very clear but it is apparant that was what he is referring to. I have done brake adjustment using the systems he referred to in his article and it has nothing to do with what I am referring to.
he only talks about the dual mc setups briefly to give you an idea of true proportioning....then...
immediatly under the "combining strategies" section he covers OEM proportioning valves in the "misnamed proportioning valve" part and then he covers the self-adjustable prop valves you find typically in towing/service vehicles in the next section "height-sensing proportioning valve".
Right after that part he talks about why you dont want to play with your factory valve (quite a nicely written piece about why you would want to convert to an adjustable valve...for marketing purposes of course ).
AFTER this the rest of the article is all about how to choose your proper mechanical PV after you've done modifications to your car.
Now...<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote »</TD></TR><TR><TD CLASS="quote">I have done brake adjustment using the systems he referred to in his article and it has nothing to do with what I am referring to</TD></TR></TABLE> and <TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote »</TD></TR><TR><TD CLASS="quote">the proportioning valve has nothing to do with pressure distribution.......in a hydraulic system all pressures equalize over time.</TD></TR></TABLE>
I present you with this from the article: Conventional proportioning valves should really be referred to as “braking force regulators” or “brake pressure regulating valves.” While their name might imply true proportional control, in reality they provide a combination of the control found in Figures A and B.
Up to certain pressures, these valves allow equal pressure to both the front and rear brakes (à la Figure A). However, once a preset pressure point is reached (600 psi in the example), the rear brake pressure continues to build, but at a slower rate (or slope) than the front brake pressure. Figure C displays this for us quite clearly.
which pretty much rips apart your second quote.
one last thing.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote »</TD></TR><TR><TD CLASS="quote">There are tons of people in Honda Challenge racing with stock drum prop valves racing with 4 wheel disc. If the prop valve adversely effected the vehicle, none of them would even touch the stock unit, except to remove it.</TD></TR></TABLE>
It cant adversely affect the vechile in racing conditions due to this statement: However, one can also see that Type C systems—those that use proportioning valves—can bring us closer to optimum balance at lower deceleration levels. This benefit is relatively meaningless in a racing application, as the vehicle is always operating at maximum decelerations, but it is of great advantage on the street.
basically the reason the racing guys can get away with it is because you cant even feel it on the track, you're always slamming the brakes above what is happening on the street where you'd be slowly stopping in traffic at a light and you'd experience brake fade...versus at the track and slamming it before turning into an apex at 60+mph.
I still stand by my recommendation of switching to a proper PV from the disc setup you are using from the donor car. Honda would not re-engineer the wheel every time it changes something on its brake setups if it didnt have to...not cost effective. plain and simple.
one last quote from the article: Of course if you have modified your vehicle in a way that impacts front-to-rear bias you might be standing out in left field! As a refresher from our bias article, we will bring forward again the lists of modifications which can influence front-to-rear bias.
Factors that will increase front bias
Increased front rotor diameter
Increased front brake pad coefficient of friction
Increased front caliper piston diameter(s)
Decreased rear rotor diameter
Decreased rear brake pad coefficient of friction
Decreased rear caliper piston diameter(s)
Lower center of gravity (i.e. lowered vehicle)
More weight on rear axle (i.e. loaded)
Less weight on front axle
Less sticky tires (lower deceleration limit)
Factors that will increase rear bias
Increased rear rotor diameter
Increased rear brake pad coefficient of friction Increased rear caliper piston diameter(s)
Decreased front rotor diameter
Decreased front brake pad coefficient of friction
Decreased front caliper piston diameter(s)
Higher center of gravity (i.e. raised vehicle)
Less weight on rear axle (i.e. unloaded)
More weight on front axle
More sticky tires (higher deceleration limit)
when you go from a rear drum to rear disc you ARE increasing the rear piston diameter! drums use a tiny little piston with a dead backing to press the drum pads out to the rotor. The disc uses a larger piston to push the pad against the rotor AND pull the outer one in against the rotor. This change in piston size DOES change the bias and you MUST compensate for it.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by stackz »</TD></TR><TR><TD CLASS="quote">
drums use a tiny little piston with a dead backing to press the drum pads out to the rotor. The disc uses a larger piston to push the pad against the rotor AND pull the outer one in against the rotor. This change in piston size DOES change the bias and you MUST compensate for it.</TD></TR></TABLE>
I do agree with the fact you do need to have the correct valve for you application, when comparing drums to discs it isn't quite as you explained. On a drum brake the wheel cylinder does push on both shoes at the same time. There are significant differences in the way a drum brake works vs disc so you can't really say the difference in size piston is the reason there is a change in bias. When a wheel cylinder presses on a brake shoe it isn't a 1:1 ratio like on disk brakes. The wheel cylinder is only pressing on one end of the shoe and the other half is stationary. The actual area of material on a brake shoe probably makes a difference as well.
I actually swapped to teg brakes all around on my EK. Whenver I did the swap I did the front brakes by themselves and drove the car. One thing I noticed when doing this the car was extremely front biased as you would expect, and the brake pedal was extremely low. After swapping the discs on the rear the car seemed less front biased and the pedal was alot higher. The car actually still seems pretty front biased with the teg calipers on the front. I am going to try using ex/si front caliper which are supposed to have a smaller pistons in them.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by cruizinmax »</TD></TR><TR><TD CLASS="quote">
I do agree with the fact you do need to have the correct valve for you application, when comparing drums to discs it isn't quite as you explained. On a drum brake the wheel cylinder does push on both shoes at the same time. There are significant differences in the way a drum brake works vs disc so you can't really say the difference in size piston is the reason there is a change in bias. </TD></TR></TABLE>
I know it wasnt exactly as I explained. I was just touching on it because I realized I was going on and on in my post and didnt want an entire page of the thread to be my post is all. I cut out info and reworded a bunch of my sentences to get the size of my post down.
Re: Proportioning valves explained and why it is not necessary to change them
I don't even care that I am bringing an old thread back. I can can guarantee that there are slight differences in the proportioning valve. When I did a rear disc swap in my HX, the brakes were amazing. Stopped almost on a dime. When I swapped them over to my EX, the brakes aren't as great.
I believe the DX, CX, HX, and Si are the same prop valve. Since the first 3 have smaller front brakes, along with the drums, it works great. Now with the Si having bigger fronts and disc in the rear, the proportioning is about the same.
Now the EX has a different part number than all of them (and two part numbers based on if it has ABS or not.) It also has larger front brakes like the Si, but with drums in the rear. When you put discs on the EX, the proportioning is a bit off. Yeah it stops, but not as great.
I am about to swap out a prop valve from a DX, CX, or HX, and see how the brakes do. I called Honda and got the part number for a 2000 Si. The part number i originally got was on a Honda parts site. (Majestic Honda)
Re: Proportioning valves explained and why it is not necessary to change them
Originally Posted by ThiRteeN
I don't even care that I am bringing an old thread back. I can can guarantee that there are slight differences in the proportioning valve. When I did a rear disc swap in my HX, the brakes were amazing. Stopped almost on a dime. When I swapped them over to my EX, the brakes aren't as great.
I believe the DX, CX, HX, and Si are the same prop valve. Since the first 3 have smaller front brakes, along with the drums, it works great. Now with the Si having bigger fronts and disc in the rear, the proportioning is about the same.
Now the EX has a different part number than all of them (and two part numbers based on if it has ABS or not.) It also has larger front brakes like the Si, but with drums in the rear. When you put discs on the EX, the proportioning is a bit off. Yeah it stops, but not as great.
I am about to swap out a prop valve from a DX, CX, or HX, and see how the brakes do. I called Honda and got the part number for a 2000 Si. The part number i originally got was on a Honda parts site. (Majestic Honda)
I’m running a stock Civic VX (3030) prop valve with Spoon twin block calipers front and ITR calipers rear. Upgraded the master cylinder to aftermarket 91 Civic EX. Brakes work great.
11-28-2005, 06:38 PM
Re: (fast88std)
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