converting WRX to use dual master cylinders
04-04-2004, 04:10 PM
#1
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converting WRX to use dual master cylinders
i don't suppose anyone out there has converted a WRX to use dual master cylinders for the braking system? i'm looking for some information on which master cylinders might be used to accomlish this, and allow me to install a brake bias adjuster in the car.
04-04-2004, 08:08 PM
#2
@Stoptech
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you want to do this for a daily driver?
just so you know, this would require omission of the ABS system. i know it sounds cool to say, "it sucks anyway, i'm probably better off without it." but the truth is that you're far worse off without ABS even though the WRX wasn't exactly blessed with the best system on the face of the earth.
if you don't mind my asking, why would you want to get a dual master cylinder setup when there are bolt on systems out there that allow you to replace your front rotor and caliper, keep the rest of the system stock, and get truly incredible braking performance?
i'm willing to help you go down this path, but i would like to make you fully aware of what you're getting into so that you don't look back $5000 and who knows how many hours of work later and say, "god i wish i had done this another way." i've seen it too many times, and it's not something i enjoy.
i'm not trying to scare you, i just want you to make sure you have a well thought out plan so you don't end up wasting large amounts of your time and money. feel free to contact me if you've got any questions at tim at stoptech.com
just so you know, this would require omission of the ABS system. i know it sounds cool to say, "it sucks anyway, i'm probably better off without it." but the truth is that you're far worse off without ABS even though the WRX wasn't exactly blessed with the best system on the face of the earth.
if you don't mind my asking, why would you want to get a dual master cylinder setup when there are bolt on systems out there that allow you to replace your front rotor and caliper, keep the rest of the system stock, and get truly incredible braking performance?
i'm willing to help you go down this path, but i would like to make you fully aware of what you're getting into so that you don't look back $5000 and who knows how many hours of work later and say, "god i wish i had done this another way." i've seen it too many times, and it's not something i enjoy.
i'm not trying to scare you, i just want you to make sure you have a well thought out plan so you don't end up wasting large amounts of your time and money. feel free to contact me if you've got any questions at tim at stoptech.com
Last edited by Steppin Razor; 04-04-2004 at 08:26 PM.
04-04-2004, 09:31 PM
#3
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in point of fact, i have actually disabled the ABS system, so i'm not terribly concerned about that. the WRX does have a poor ABS system, and i learned to drive on cars without ABS anyway. given my experience with non-ABS cars, i'm not inclined to agree with you about being better off with the ABS on, but thats just my opinion.
the rationale behind installing dual master cylinders is pretty simple. i don't know of a way to fine tune the front/rear brake balance in the car without it. yeah, you can change pads, and discs, and rotors, but you aren't going to get the adjustability of a balance controller. most of the BBKs on the market provide all the clamping force that you could possibly wish for. hell, the stock system has plenty of clamping power, and the only real reason for most drivers to upgrade is increased thermal capacity and heat dissipation. however, its not clamping force that makes a car stop quicker.
most big brake kits only address the front brakes. on stock cars, the brake balance is a little front heavy, so the front wheels will
lock before the rears. when you change the car's suspension (making it stiffer), you change the amount of weight transfer under braking, and the brake bias changes as well, becoming more front biased. as such, you're giving up stopping power in the rear, since the front brakes are locking much sooner than the rears under braking. by taking advantage of the increase in rear wheel grip, you're able to stop more quickly -- but to do this you need to increase the amount of rear brake bias.
right now, i'm really just looking at what such a project would take. i'm not likely to spend $5k on it, thats for damn sure.
edit: i'm currently using Subaru 4 pot fronts on stock (for now) rotors with Axxis Ultimates, and the stock rear caliper and rotor combo with Axxis Ultimates.
the rationale behind installing dual master cylinders is pretty simple. i don't know of a way to fine tune the front/rear brake balance in the car without it. yeah, you can change pads, and discs, and rotors, but you aren't going to get the adjustability of a balance controller. most of the BBKs on the market provide all the clamping force that you could possibly wish for. hell, the stock system has plenty of clamping power, and the only real reason for most drivers to upgrade is increased thermal capacity and heat dissipation. however, its not clamping force that makes a car stop quicker.
most big brake kits only address the front brakes. on stock cars, the brake balance is a little front heavy, so the front wheels will
lock before the rears. when you change the car's suspension (making it stiffer), you change the amount of weight transfer under braking, and the brake bias changes as well, becoming more front biased. as such, you're giving up stopping power in the rear, since the front brakes are locking much sooner than the rears under braking. by taking advantage of the increase in rear wheel grip, you're able to stop more quickly -- but to do this you need to increase the amount of rear brake bias.
right now, i'm really just looking at what such a project would take. i'm not likely to spend $5k on it, thats for damn sure.
edit: i'm currently using Subaru 4 pot fronts on stock (for now) rotors with Axxis Ultimates, and the stock rear caliper and rotor combo with Axxis Ultimates.
Last edited by dropkick_muppet; 04-04-2004 at 09:38 PM.
04-05-2004, 05:18 PM
#4
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I owe my life to the ABS in the WRX...don't pull it out...just leave it the way it is man. What would you want two master cylinders for? My buddies 'froader truck has them but he races in the Baja 500 and claims he needs it. Seems like a waste in a car.
04-05-2004, 10:44 PM
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how many times do i have to tell people this, practically every (and i do mean every) vehicle that i've ever owned before the WRX has not had ABS! i learned how to drive and ride with brakes that would lock up and slide if you didn't modulate them, and i'm quite used to it.
as for needing two master cylinders, that was pretty much covered in my original post. with one master cylinder, the only way to change the cars front/rear brake balance is the change hard parts like calipers, rotors, and pads.
as for needing two master cylinders, that was pretty much covered in my original post. with one master cylinder, the only way to change the cars front/rear brake balance is the change hard parts like calipers, rotors, and pads.
04-07-2004, 02:11 PM
#6
dropkick,
We have removed ABS and rerouted our lines from diagonal to front/rear in order to use a cockpit adjustable brake proportioning valve. Our rules don't allow replacing the master cylinder or we would have done a dual master setup. I'm assuming you are talking about a dual master cylinder system with a balance bar, correct?
You may want to give Tilton or AP a call and speak to one of their tech guys regarding this. I imagine it will be fairly intensive requiring a pedal box replacement, removal of the factory vacuum assist, etc.
Good luck.
Gary
Sheehan Motor Racing
www.teamSMR.com
We have removed ABS and rerouted our lines from diagonal to front/rear in order to use a cockpit adjustable brake proportioning valve. Our rules don't allow replacing the master cylinder or we would have done a dual master setup. I'm assuming you are talking about a dual master cylinder system with a balance bar, correct?
You may want to give Tilton or AP a call and speak to one of their tech guys regarding this. I imagine it will be fairly intensive requiring a pedal box replacement, removal of the factory vacuum assist, etc.
Good luck.
Gary
Sheehan Motor Racing
www.teamSMR.com
04-07-2004, 02:58 PM
#7
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Gary,
yes, you're correct. i was thinking of going with dual master cylinders to allow the use of a balance bar. it sounds like the route that you took would be a hell of a lot simpler than replacing the m/c/pedal box etc. i'll look into that, thanks.
yes, you're correct. i was thinking of going with dual master cylinders to allow the use of a balance bar. it sounds like the route that you took would be a hell of a lot simpler than replacing the m/c/pedal box etc. i'll look into that, thanks.
04-09-2004, 08:35 AM
#8
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You'll also want to read this: http://www.stoptech.com/whitepapers/...ing_valves.htm
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