Hey guys! I was wondering what some of you guys have done to upgrade you're master cylinders? Looking for a nice bolt-in setup, but little modifications I'm okay with! preferably 1".
Thanks

 

in the FC I've done several 929 swaps, which uses the master/booster/prop valve all from a 929. Just eye balling it (sorry, i can only offer you the idea ) It looks like the major hurdle would be shifting the clutch master out further toward the fender, for space reasons. Definitely worth looking into, however.

 

I know someone who did a Wilwood install, he seems to like it a lot.

 

Nice nice! Ive seen that done on some threads looks like an option.

 

I was looking at those M/Cs and was thinking they look similar. Was it a direct bolt in?
Thanks

 

I can't remember what he said, I'll ask him and see how it went. I don't think it was too hard though. He also went LS3 V8 with a T56 6-speed behind it - but didn't change the clutch master cylinder mounting location so it should be the same.

 

Just interested. Why do you want to change the master cylinder?

 

MCs with larger pistons are said to give better brake feel. A lesser range of motion is required to move the same amount of brake fluid, leading to firmer pedal feel.

 

But you also have to push harder to make up for the larger diameter piston.

Stainless braided hoses and well maintained stock MC and calipers gives me very firm high pedal in my ITA car.

I will be interested to hear how you swap turns out.

 

Well Im entertaining the idea of doing a brake booster delete, and in the future a big brake kit. So to compensate for the lack of power assist the bigger piston master will allow me to get a bit more brake apply force. And Im in the market for a new master anyway as I am gathering parts to finish the restomod, so If I can get a bigger better one I might as well.
I completely agree and math doesn't lie. If you have a larger diameter M/C piston, and even if you use the same amount of pedal pressure as you would a smaller (stock) diameter piston you will have more hydraulic pressure. More Pressure in the hydraulic system, more force applied to the caliper piston. Not to mention the brake pedal its self is a lever which adds mechanical advantage which outputs even more! .

 

Math definitely does not lie and it clearly says that a larger diameter piston will give less output pressure than a small diameter piston for the same pedal pressure. If you have a MC with 1 square inch bore (that would be a bit bigger than 1" diameter piston) and apply 200 lb of force to the input side of the piston (say 100 lb by your leg multiplied by 2 through the lever of the pedal) than the pressure generated in the system would be 200 lb/sqin. If you go to a larger piston with 2 sqin bore (about 1.6" diameter), then the fluid pressure generated at the outlet of the piston will be 100 lb/sqin (200lb force divided by 2 sqin).

So smaller MC means more pressure and larger MC means more fluid moved for same stroke. If you remove the brake booster you really want a smaller MC if you want to use the same pedal pressure.

Using larger brake rotors though can make up for the loss of pressure/force in other parts of the system.

If you go with big brakes, I definitely recommend doing both front and rear. I just did a conversion on our race car with fronts only and it was scary bad. Maybe OK for driving around on the street, but not when you really need the brakes. We then added big rear brakes to balance the rotor sizes front to rear and ended up with a really nice braking system. Not really needed for street driving or sprint racing, but absolutely bulletproof for endurance racing (8-14 hours at a time) due to the bigger rotor and pad mass.

I am heading out of town for the weekend, but when I get back I will post a link to a really good site that gives all the math for getting a good balanced brake system.

 

For really good explanations of brake systems, search on "James Walker brakes". Here is a link to part 3 (and I think 1 and 2) of an article he did for GRM. It explains things in a very straightforward manner.

Braking in plain English article, Brakes - Part 3, FAQ, FFR FAQ

Carl

 

bump

i am adding larger brakes front (4 pistion) and rear, looking for a m/c upgrade

 

I just installed a brake booster from a 323 to give me more options on brake masters. With the 323 booster, it installs perfectly. It is the same size as the FB booser, but has to studs that are horizontal and not vertical.

After you have the booster that has horizontal studs you have opened up A LOT of options for brake masters.

I tried an FC booser first, but that wont work with out some signifigant modifaction. Same with the miata stuff.

 

Sorry to revive this thread, but i went with TII brakes all around for my FB.
You said you upgraded all 4 corners and it felt good. Did you make any changes to the MC or the prop valve?

Thanks.

 

what year 323 booster did u use?

 

I have FD front calipers on FC rotors with Endless brake pads, and Nissan rear calipers & rotors, using the FC turbo booster and a WRX 1" master and aftermarket adjustable brake prop valve. Car stops like it's hit a wall.

 

Thanks for the response