question about brake master cylinder

[matias88e30]

Im getting parts together to rebuilt all calipers, get new rotors, pads and lines as well a main pump... my question is:
Is there any upgrade in the master cylynder pump from another bimmer? or should i just get a oem one?
I had only replace rotors and pads since i bought the car, anything else in brake system, but everything its oriiginall and car its a 88, i think its time to upgrade all parts mentioned... thansk for any help

[FredK]

If I were you, I would just get a stock master cylinder. There is a larger one that isn't necessarily better (IMO it's worse for modulation) from an E32 735i that people often "upgrade" to.

[Massive Lee]

Hi Matias

What improvement are you expecting from an "upgraded" MC?

[matias88e30]

FREDK: thanks.. i will do some research about it!

MASSIVE LEE: just looking for lees pedal travel and hard braking.. i drove my friend 240 he just swapped a 300zxtt master cylinder and u can feel the difference, i drove it with stock pump and with the 300zx pump, i kno its not a e30 but just to have an idea.. thanks

[Massive Lee]

With a bigger MC, you will end up with less pedal travel and more force required to press the brakes to the SAME pressure at the caliper. Therefore, as you now understand it doesn't equal to harder braking. It is just harder to press the pedal.

If you increase the size of the MC, I suggest also increasing the grip of the pads. Many people fantasize about boosterless racing set-up. But they also forget that racecars run pads with very high friction. And for only 20 minutes at a time.

I have once tested some race-only compound for heavy NASCAR vehicules. With a booster, if you barely breath on the brakes, it will lock-up the wheels. Not good.

[matias88e30]

^^ thanks man! i did some reading last night about the e32 735 pump and honestly it didnt convince me.. i would love to afford one of ur setups!! but i cant right now! lol.. i love the way she brakes even with 20+ years old parts... so i might go with oem!...

[nando]

but if you're tired of a mushy pedal - is there any harm to the larger MC? how much harder is it to press, is it linear? the area difference is about 5mm^2, does that mean it will be 25% stiffer?

the reason I ask - I can get a brand new 735i MC that is 100% bolt on for the ix for way less than an ix MC..

[FredK]

Yes. With an iX booster, there's sufficient boost that a larger MC will probably benefit you if you feel you need more modulation.

http://e30m3project.com/e30m3performance/installs/installs-1/25mc/25mc.htm

[nando]

is the ix booster larger volume or something?

[FredK]

I believe the iX booster has more assist than a regular E30 booster.

[nando]

ok - I think it's a no brainer then. if I don't like it, they have a 22mm rebuild kit for $65.

it's sort of sad that my brakes felt better when the car was 100% stock 9 years ago..

[nando]

Went for it - $153 at NAPA. I think this will be a good thing! Even freshly bled i can push hard enough to almost touch the floor...