Got the BIG brake kit for my baby!!
#76
Super Snuggles
Originally Posted by maxcooper
It does change the bias, though, which is how this whole discussion got started.
The 99 rears help balance out a big brake kit, but the rear brakes I have were designed specifically because some smart people worked it out and found that the 99 rears were not enough to give proper balance with the front kit that I have. So the 99 rears don't fully balance out any front upgrade
Your 13.0" front rotors are about 12% larger than the stock 11.6" rotors. In the rear, your 12.2" Precision Brakes rotors are about 5% larger than stock, so that's a ~7% imbalance, give or take. If you increased the rear rotor diameter to 13.0" also and moved the caliper a corresponding amount, you'd probably have a pretty good match for a front kit. Not perfect, but pretty damn good. Maybe someone should make a bracket.
Still, it's better to have less rear brake bias than it is to have too much rear brake bias.
#77
Eats, Sleeps, Dreams Rotary
iTrader: (17)
Originally Posted by neit_jnf
don't these change the brake bias (balance) towards the front too much?? or is there a matching rear kit?
Originally Posted by superior_force
little ccw canadian boy had no idea he was opening up a major technical discussion with the forum elders
I'm Puertorrican btw...
#79
Originally Posted by jimlab
Your 13.0" front rotors are about 12% larger than the stock 11.6" rotors. In the rear, your 12.2" Precision Brakes rotors are about 5% larger than stock, so that's a ~7% imbalance, give or take. If you increased the rear rotor diameter to 13.0" also and moved the caliper a corresponding amount, you'd probably have a pretty good match for a front kit. Not perfect, but pretty damn good. Maybe someone should make a bracket.
FRONT:
stock = 1.42" + 1.42" pistons = 3.17 square inches
RZ = 1.33" + 1.5" pistons = 3.17 square inches
AP 4-pot = 1.5" + 1.63" pistons = 3.84 square inches (+21%)
REAR:
stock, RZ = 1.37" piston = 1.48 square inches
Wilwood NDL = 1.12" + 1.12" pistons = 1.97 square inches (+33%)
(Note that you only count one side, or half the total area, for calipers that have pistons on both sides. You count the full area for calipers that only have pistons on one side, like the Mazda rear calipers.)
So, I don't have any specific calculations, but I have a larger piston area increase over stock in the rear, and I suppose that helps to balance out the larger rotor diameter increase in front.
Originally Posted by jimlab
Still, it's better to have less rear brake bias than it is to have too much rear brake bias.
-Max
#80
Super Snuggles
Originally Posted by neit_jnf
I'm surprised my comment above started this great discussion
I'm Puertorrican btw...
I'm Puertorrican btw...
He was referring to the original poster, ccw998.
#81
Super Snuggles
Originally Posted by maxcooper
Very true. But I can tell you that way-too-much front bias feels like crap.
#82
NYC's Loudest FD
I know we're talking about the 929 master cylinder here. I think Fujita Engineering(FEED) may offer the same thing with an adapted brake line, here's a pic of it:
I can't read Japanese, so I couldn't get any info on it, can someone check to see what it reads and let us know?
Here's the link to the website with the info:
http://www.pac-gate.co.jp/feed/index.html
I can't read Japanese, so I couldn't get any info on it, can someone check to see what it reads and let us know?
Here's the link to the website with the info:
http://www.pac-gate.co.jp/feed/index.html
Last edited by RX794; 04-04-05 at 06:48 PM.
#85
Lives on the Forum
Join Date: Dec 2001
Location: San Lorenzo, California
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Originally Posted by fd3s777
hehehe I got my brake from a 2001 FD. brakes are larger (330mm) I do really feel they brake alot better than U.S spec.
There will be zero difference in stopping power on the the street between those and the OEM 93-95 brakes, except from speeds that exceed the ABS threshold (hint, very high). It is certainly possible that they have better feel than your old brakes, and they probably require less pedal effort/distance as well.
#90
Banned. I got OWNED!!!
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See what you guys did..
Now he's selling his brakes..
https://www.rx7club.com/showthread.php?t=424091
Now he's selling his brakes..
https://www.rx7club.com/showthread.php?t=424091
Last edited by SlingShotRX7; 09-05-05 at 09:49 PM.
#91
Rotary Freak
Originally Posted by patfat
Big brakes for autoX?? Why? Maybe I'm drunk or maybe you wasted your money
#92
I
iTrader: (3)
wow holy crap, this is kinda funny, cause i just learned all thise brake crap in my AST program and forgot it all, but i beileve the reasont the 929 master cylinder will incresase brake efectiveness is rather simple i believe. the whole design behind the internals of the 929's probly allow it to shift more brake fluid at once, thus resluting in the brake pedal being depressed less then originaly, but same amount of flius shifting. Also if you put 50lbs onto the brake pedal with stock setup then change it to a Big Brake kit setup, then you will still put 50lbs worth of pressure on the brake pedal but since the amount of fliud that needs to get shifted is higher the pedal falls father to the floor. In the 929 i believe that it shifts more brake fluid through the lines therfore "stiffing" the pedal feel, this should also allow for harder braking applications because you can shift more fliud in the same amount of pedal travel. well thats my ranting and raving, i'll try to help clear this mess up if i can in the next few days.
Prôdigy
Prôdigy
#93
2/4 wheel cornering fiend
It's called "master cylinder piston ratio", and although I've heard good things about the 929 master cylinder used with brake upgrades, simply going to a larger master cylinder piston on any application won't necessarily "allow for harder braking applications" because if you use too high of a piston ratio, the brakes become "grabby" and lose a lot of feel and modulation.
#94
Banned. I got OWNED!!!
Join Date: Oct 2005
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the stock master cylinder is notorious for spongy feel and lack of initial bite....I've talked to several people who said the 929 makes a night and day difference with the stock brakes
I'll follow up as soon as I get mine installed
I'll follow up as soon as I get mine installed