Is there a Brake Master Cylinder Upgrade for Big Brake Kit?

[repoman89]

I have Stoptechs front and rear and the brake pedal is a little less firm early on which I'm fine with. Better than the on/off feel of the OE brakes but most people prefer the immediately stiff pedal.

I have the 996 brakes and 100% agreed. Pedal has a little more travel than stock but combined with hard compound track pads it makes modulation much easier. For me it puts the pedal in just the right range for heel toe while threshold braking.

I put the E65 MC in my E39 M5 though and that was a big improvement. Those brakes have way too much travel.

[heinzboehmer]

How does a bigger master cylinder interact with the DSC system? My immediate thought is that it would throw some of the logic off for ABS/traction control thresholds.

[eacmen]

How does a bigger master cylinder interact with the DSC system? My immediate thought is that it would throw some of the logic off for ABS/traction control thresholds.

Larger MC yields less pressure for same pedal travel. I dont actually think that a larger MC will necessarily throw the ABS or DSC out of whack that much as the value in the brake system they care about measuring is brake pressure.

From an ABS standpoint I think it would actually work just fine. But according to Lee at massive brakes the ABS may actually damage the pistons in the master cylinder if they arent designed to be used with ABS.

DSC, I think the same thing applies - the brake pressure sensors will still measure the correct pressure going to each brake circuit.

What I think mess up the ABS/DSC the most is brake bias being out of whack. So if you choose a master cylinder where the bias is much different than stock the ABS and DSC will be unhappy. Similar issues when installing BBKs to be honest.

I dont have any direct experience with this so take it with a grain of salt.

[heinzboehmer]

Larger MC yields less pressure for same pedal travel. I dont actually think that a larger MC will necessarily throw the ABS or DSC out of whack that much as the value in the brake system they care about measuring is brake pressure.

From an ABS standpoint I think it would actually work just fine. But according to Lee at massive brakes the ABS may actually damage the pistons in the master cylinder if they arent designed to be used with ABS.

DSC, I think the same thing applies - the brake pressure sensors will still measure the correct pressure going to each brake circuit.

What I think mess up the ABS/DSC the most is brake bias being out of whack. So if you choose a master cylinder where the bias is much different than stock the ABS and DSC will be unhappy. Similar issues when installing BBKs to be honest.

I dont have any direct experience with this so take it with a grain of salt.

Yeah, actually what you're saying does make sense. The only factors the DSC has to work off are brake pressure, wheel speed and data from the DSC sensor. So was thinking that messing with the brake pressure might confuse it a bit. But I guess as long as you keep the brake bias consistent, you should be okay, as the torque at the wheels vs brake pressure curve should be the same as the stock one. The only thing that might change is the point along the pedal's travel at which that pressure is reached.

[mrgizmo04]

Your problem can be solved by removing the rear F40 kit. It is a subpar kit and displaces too much fluid based on piston sizes and prob is not needed for performance on our cars. 345mm rear rotor?

F50 and F40 are kits that actually came from respective Ferraris of the 90s. Even F40 owners complained about their brakes.

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[Tjperry91]

Did you try the e65 master cylinder on your e46 m3? I am thinking about doing this. Wondering why there are three hardline ports on the e65 cylinder though ?