Controlling brake bias with adj proportioning valve? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

95Blue240sx · 07-03-2004, 08:05 AM

i was thinking of getting an adjustable proportioning valve to try and reduce the front end diving when hard braking. putting in a adj proportioning valve would do just that, but im wondering if it is worth it and your guys' opinions. for the brakes i only have the z32s up front. i notice when the rear breaks get warm the car breaks awsome, but i still get some hard braking in front. would putting in the adj valve be a waste? would it just be a waste of putting on the z32s in the first place, since im reducing pressure up front? kinda of hard to say what i mean, but ill post more when i know what to say, thanks.

BJ

thx247 · 07-03-2004, 10:01 AM

A bias valve for the front would be somewhat difficult to install unless you had ABS. ABS has a single brake line coming from the master cylinder, non ABS has a brake line for each side of the front.

You can try balancing the brakes out more by putting a more agressive pad in the rear, or putting a less aggressive pad in the front. Its alot easier to drive a car with lots of front bias and too little rear bias, than it is to drive a car with just a little too much rear bias.

MovinUp-1 · 07-03-2004, 07:07 PM

There are a lot of things that can control brake dive, but putting a proportioning valve on your front brakes is quite dangerous. An adjustable proportioning valve limits the flow of brake fluid to the caliper. You would effectively be reducing the amount of braking force you have on the front of the car and thus reducing your ability to stop. That's not a good thing.

If you want to reduct brake dive you do it with spring, shocks and some other things like your differential pinion angle.

*sykikchimp* · 07-06-2004, 01:14 PM

If you were to use a proportioning valve you would want to remove the stock bias valve in the M/C, and put the prop. valve on the rear channel. (you'd have to combine, and redistribute.)

The 300zx calipers definately add some front bias though. A better way to help out would be to install a z32 MC. I believe they come stock with a higher split point (more rear bias) than the s14 MC's did.

thx247 · 07-06-2004, 09:08 PM

No need to combine, there is a single line that goes to the rear, and its even been cut and split for you just under the fuel filter. Just find the right fittings and goto town.

*sykikchimp* · 07-07-2004, 10:07 AM

ahhh.. duh. For whatever reason, I was all backwards in my head. Thanks!

07-03-2004, 08:05 AM	#1
95Blue240sx Post Whore! Join Date: Jul 2002 Location: Girls pee-pee when they see me Age: 40 Posts: 4,084 Trader Rating: (0) Rides Gallery: 95Blue240sx Feedback Score: 0 reviews	Controlling brake bias with adj proportioning valve? i was thinking of getting an adjustable proportioning valve to try and reduce the front end diving when hard braking. putting in a adj proportioning valve would do just that, but im wondering if it is worth it and your guys' opinions. for the brakes i only have the z32s up front. i notice when the rear breaks get warm the car breaks awsome, but i still get some hard braking in front. would putting in the adj valve be a waste? would it just be a waste of putting on the z32s in the first place, since im reducing pressure up front? kinda of hard to say what i mean, but ill post more when i know what to say, thanks. BJ __________________ Please leave me feedback

07-03-2004, 07:07 PM	#3
MovinUp-1 Zilvia Member Join Date: Jul 2002 Location: Now I'm in Texas Posts: 243 Trader Rating: (0) Feedback Score: 0 reviews	There are a lot of things that can control brake dive, but putting a proportioning valve on your front brakes is quite dangerous. An adjustable proportioning valve limits the flow of brake fluid to the caliper. You would effectively be reducing the amount of braking force you have on the front of the car and thus reducing your ability to stop. That's not a good thing. If you want to reduct brake dive you do it with spring, shocks and some other things like your differential pinion angle. __________________ Allen Delta Region SCCA SM 1990 240SX SR20DET

07-06-2004, 01:14 PM	#4
sykikchimp WOW addicted Join Date: Dec 2001 Location: the moon Age: 43 Posts: 6,525 Trader Rating: (0) Feedback Score: 0 reviews	If you were to use a proportioning valve you would want to remove the stock bias valve in the M/C, and put the prop. valve on the rear channel. (you'd have to combine, and redistribute.) The 300zx calipers definately add some front bias though. A better way to help out would be to install a z32 MC. I believe they come stock with a higher split point (more rear bias) than the s14 MC's did. __________________

07-07-2004, 10:07 AM	#6
sykikchimp WOW addicted Join Date: Dec 2001 Location: the moon Age: 43 Posts: 6,525 Trader Rating: (0) Feedback Score: 0 reviews	ahhh.. duh. For whatever reason, I was all backwards in my head. Thanks! __________________

07-03-2004, 10:01 AM	#2
thx247 Zilvia FREAK! Join Date: Jan 2003 Location: bay area Posts: 1,455 Trader Rating: (0) Feedback Score: 0 reviews	A bias valve for the front would be somewhat difficult to install unless you had ABS. ABS has a single brake line coming from the master cylinder, non ABS has a brake line for each side of the front. You can try balancing the brakes out more by putting a more agressive pad in the rear, or putting a less aggressive pad in the front. Its alot easier to drive a car with lots of front bias and too little rear bias, than it is to drive a car with just a little too much rear bias.

07-06-2004, 09:08 PM	#5
thx247 Zilvia FREAK! Join Date: Jan 2003 Location: bay area Posts: 1,455 Trader Rating: (0) Feedback Score: 0 reviews	No need to combine, there is a single line that goes to the rear, and its even been cut and split for you just under the fuel filter. Just find the right fittings and goto town.