I was wondering, while talking to Todd regarding the purchase of a 6 piston brake kit, he mentioned to me about using the gsx master cylinder for a better pedal feel.
I was wondering if anyone has done this with their brake upgrades, and if so what exactly do we have to change? do we need to change the master only, or do we have to change the master and the booster and other associated piping.
Thanks
james

i dunno 'bout anyone swapping the master. i think most people just swapped calipers an rotors. i upgraded to gsx calipers and got some AEM rotors (slotted and crossdrilled).

-marc

='95 RS 5spd Red=
Matrix Type X CAI || A'pexi N1 Turbo || Viper 500esp || Indiglo Gauges || Hanabi 9000k HID Kit || SPAL Deluxe Power Windows || Power Trunk Release || Nakayam GT-5 Silver 17x7 || Kumho ECSTA Supra 712 215/45/17 || Silver Dual Piston Calipers || Silver AEM AWD Rotors || SS Brake Lines || Metal Master Brake Pads

From what I know the master cylinder is the same on all the 2g's. The only thing different on the AWD's is the porportioning valve. I was told this by a Chrysler tech. I have not checked into it though....

hmm, todd said to use a 1" master, i dunno if ours is 1 inch or not
but he said it was from a gsx. I have a gs wiith 4 wheel disks, so i wonder if it is the same.
lates
james

To quote my former rollmodel Gus Mahon, "Wrongo." The GSX has a 1" master cylinder, where us FWDs (regardless of disc or drum in the rear) have 15/16" We will get a better feel with a smaller master cylinder, as each pound of pressure on the brake pedal translates into fewer pounds of pressure of pressure on the rotor. The advantage of the 1" master cylinder, though, is that you can push more brake fluid per inch of travel then you can with a 15/16" master cylinder. Basically, you get more travel and better feel with a smaller master cylinder, but it is tough to use really big brakes with a smaller master cylinder, and translates into a heavier brake pedal. This isn't a problem for us, though, with vacuum based brake assist.

Big MC: less pedal effort and travel, less brake feel.
Small MC: heavier brake travel, more travel, better feel for braking.

-=B-=

cool cool,
i know a smaller master will give us more pedal feedback, but i didn't know it was only a 1/16 inch difference. well, screw it then. i'm just going to get the brakes and use the standard master cylinder. then i will worry about changing the MC laters.
thanks
james

Don't worry about changing the brake master cylinder. I believe Bill is right about the GSX being 1". In addition to this, AWD DSMs have a proportioning valve. Without adding a proportioning valve, our front brakes will indeed be used more than our initial stock setup. If you really want, you can buy a proportioning valve, but I think it is unnecessary to buy it and the master cylinder. Many 2G FWD with large brake upgrades are using the FWD master cylinder and are doing fine in road racing and drag racing. For my AWD Big Brake upgrade, I didn't change my master cylinder or valve.

Actually, the FWDs and the AWDs both have proportioning valves, they are just set for different proportions. The AWD seems to provide more hydraulic pressure to the rear calipers then does the FWD.
-=B-=

Opps, you're totally correct Bill about the valves. The FWD and AWD have different split points for their respective valve.

i'd recommend changing it..

The 2 piston pots need a bit more fluid to work right.

All the fwd cars use 15/16", the GSX uses 1" and the stealth uses 1-1/16" master cylinders.

I like stiff brakes.. i like sticky tires.. the only feel i need is the tire lockin up.. just pay attention to the rearview mirror when stopping.. just cause you can now stop on a dime, doesn't mean the idiot behind you can..

oh ya..

the stealth and the GSX use a dual diaphram design in the brake booster.. more power assist ;-)

-- WheatKing

okay i have never taken a brake booster apart, can someone explain the inner mechanical workings on how exactly this large vacuum chamber boosts our brakes?
thanks
James

Yeah, VR-4 master cylinder would be fun. Wonder which proportioning valve I want... I might go with the early '95 vented rear rotors, with the different capipers, as they are bigger. Yummy. Also might want to try out the dual diaphragm booster, not that I know how a booster works...
hehe...
-=B-=

>Yeah, VR-4 master cylinder would be fun. Wonder which
>proportioning valve I want... I might go with the early '95
>vented rear rotors, with the different capipers, as they are
>bigger. Yummy. Also might want to try out the dual diaphragm
>booster, not that I know how a booster works...
>hehe...
>-=B-=


Stick with you proportioning valve. It determines the braking split front to back.. nothing else.. using an AWD valve will decreasing your braking, and will probably cause the rear tires to lock well before the fronts.

http://www.howstuffworks.com/power-brake.htm

-- WheatKing