[ember.m4]

With normal cars (hydraulically connected pedal), a lot of people pick brake fluids with low compressibility like the Endless RF650 over similar fluids with more compressibility like Castrol SRF to get a firmer pedal feel. The G8X are brake by wire though, so it got me thinking.

AFAIK, there's no physical connection between your pedal and your brake fluid in this car, the pedal just electronically actuates a master cylinder that then transfers the pressure to the brake system. Does this mean that's it's impossible to change the resistance curve of the pedal? I get that different fluids and pads will still "feel" different because the car's braking behavior relative to pressure applied will be affected, but IIUC the resistance curve of the pedal itself should still be the same. Is this a correct understanding?

I ask because I find the pedal to be quite soft, and it'd be nice to be able to firm it up a bit.

[chris3g]

Changing the pedal feel in relation to the actual rate of deceleration is exactly what the sport setting for the brakes is supposed to do, did you try changing it ?

[ember.m4]

Originally Posted by chris3g

Changing the pedal feel in relation to the actual rate of deceleration is exactly what the sport setting for the brakes is supposed to do, did you try changing it ?

Apologies if I wasn't clear, I don't want to change the deceleration of the car relative to the travel of the pedal (this can easily be achieved in an electronic braking system like ours), I want to change the resistance of the pedal (pressure required to depress relative to the travel of the pedal). In a hydraulic system, you can decrease the compressibility of the fluid to achieve this. I believe in ours, it is impossible since the pedal is not connected to any fluid directly, but I am double checking.

[chris3g]

Originally Posted by ember.m4

Apologies if I wasn't clear, I don't want to change the deceleration of the car relative to the travel of the pedal (this can easily be achieved in an electronic braking system like ours), I want to change the resistance of the pedal (pressure required to depress relative to the travel of the pedal). In a hydraulic system, you can decrease the compressibility of the fluid to achieve this. I believe in ours, it is impossible since the pedal is not connected to any fluid directly, but I am double checking.

Ok I see what you mean, yes I believe you’re correct that a physical change to the braking system does not result in a change in the pedal feel as there isn’t a mechanical connection there.

[mcsquared]

I wonder if stainless steel brakes lines would help with the pedal feel, in this case? I know they helped on my STi, but, being new to BMW I’m not sure if it would help pedal feel? Thoughts?

[ember.m4]

Originally Posted by mcsquared

I wonder if stainless steel brakes lines would help with the pedal feel, in this case? I know they helped on my STi, but, being new to BMW I’m not sure if it would help pedal feel? Thoughts?

For the same reason that I suspect brake fluid wouldn't, SS brake lines also wouldn't. They're all part of what comes out of the master cylinder into the braking system, which isn't physically connected to your pedal. I would expect that it would similarly change the deceleration curve, but not the physical resistance of the pedal.

[mcsquared]

Originally Posted by ember.m4

For the same reason that I suspect brake fluid wouldn't, SS brake lines also wouldn't. They're all part of what comes out of the master cylinder into the braking system, which isn't physically connected to your pedal. I would expect that it would similarly change the deceleration curve, but not the physical resistance of the pedal.

Gotcha. I’ve only test driven a couple of g80’s and didn’t have tons of seat time, but, I’m sure I’ll be able to experience the phenomenon you speak of, once my car arrives…should it ever leave Germany!

[ember.m4]

Originally Posted by mcsquared

Gotcha. I’ve only test driven a couple of g80’s and didn’t have tons of seat time, but, I’m sure I’ll be able to experience the phenomenon you speak of, once my car arrives…should it ever leave Germany!

To be fair, it's not terrible. I do think the brakes are one of the weaker parts of the car, but it's not bad by any means. It's just softer and harder to modulate than I'd like. At the same time, one can't exactly expect that a souped up sedan is going to feel like a race car

[beamlord]

Eh, I find the brakes actually super easy to modulate, even compared to my m2c.
But I have CCB brakes.

[mcsquared]

Originally Posted by beamlord

Eh, I find the brakes actually super easy to modulate, even compared to my m2c.
But I have CCB brakes.

That was going to be my next question, is whether CCB’s moght make the difference, but, again, I doubt pedal feel is changed?

Originally Posted by ember.m4

To be fair, it's not terrible. I do think the brakes are one of the weaker parts of the car, but it's not bad by any means. It's just softer and harder to modulate than I'd like. At the same time, one can't exactly expect that a souped up sedan is going to feel like a race car

True…

[ember.m4]

Originally Posted by beamlord

Eh, I find the brakes actually super easy to modulate, even compared to my m2c.
But I have CCB brakes.

Interesting. Yeah, I've never driven an F gen M car on track, so I have no idea how that comparison works out. The pedal in my G82 feels really soft, and you need a lot of travel to modulate, which ends up feeling imprecise (hard to move your foot/leg in a super linear way when it's physically moving so much). I definitely prefer the wall-like feeling of a Porsche GT car's brake pedal.

[GTS Daddy]

Someone here did SS lines and noticed a difference.

[beamlord]

Originally Posted by ember.m4

Interesting. Yeah, I've never driven an F gen M car on track, so I have no idea how that comparison works out. The pedal in my G82 feels really soft, and you need a lot of travel to modulate, which ends up feeling imprecise (hard to move your foot/leg in a super linear way when it's physically moving so much). I definitely prefer the wall-like feeling of a Porsche GT car's brake pedal.

I guess it's a personal preference, many people who drive it on track actually prefer a softer pedal response for finer granular modulation.
I even leave my settings on regular. Again, there's definitely a difference between CCB and iron brakes.

[BMWRacer523]

I doubt it will make a difference since there is no physical connection as you correctly point out. I also leave brake on comfort when on track. Brakes aren't like in a race car but I have not had any issues on stock brakes, stock pads and stock fluid. I do flush fluid every 6 months without fail. Much to the amazement of my service advisors LOL.

[ember.m4]

Originally Posted by BMWRacer523

I doubt it will make a difference since there is no physical connection as you correctly point out. I also leave brake on comfort when on track. Brakes aren't like in a race car but I have not had any issues on stock brakes, stock pads and stock fluid. I do flush fluid every 6 months without fail. Much to the amazement of my service advisors LOL.

Sigh, makes sense. Yeah, I also run comfort. Sport is just weird. It doesn't increase the resistance, it just makes the curve feel awkwardly sensitive and bite-y.

[BMWRacer523]

Originally Posted by ember.m4

Sigh, makes sense. Yeah, I also run comfort. Sport is just weird. It doesn't increase the resistance, it just makes the curve feel awkwardly sensitive and bite-y.

I also find it makes the rear somewhat unstable under heavy braking. The rear caliper in this car is a joke. But it's manageable.

[mcsquared]

Originally Posted by BMWRacer523

I also find it makes the rear somewhat unstable under heavy braking. The rear caliper in this car is a joke. But it's manageable.

Do you happen to know if it’s viable to install a larger rear brake kit and/or is one even available? I figure you guys with more M car experience would know what’s what…or perhaps the g8x series doesn’t have enough R&D into the after market, just yet?

[shwayne5]

There really isn’t much available. AP hasn’t developed theirs, but they’re estimating next month but take that with a grain of salt. They are selling a front upgrade though. Girodisc (not bigger but better than stock) is a ways out from releasing an iron brake rotor conversion for the rears. Probably EOY or first quarter. CCB to iron conversion is just as far but I don’t know this for a fact. Just based off of what I heard.

There really isn’t much for these cars. I didn’t realize it took this long to get aftermarket parts out since I’ve had mine since early 21, but it has and it’s the name of the game. I think F80 buyers went through the same timelines etc.

[mcsquared]

I went through the same with my first WRX wagon, a 2002 bugeye. And wagons always got the shaft, as there was more support for the sedan variants when they made it here.

Hopefully, there’ll be some support down the line. Waiting game, I suppose.

[ember.m4]

Originally Posted by shwayne5

There really isn’t much available. AP hasn’t developed theirs, but they’re estimating next month but take that with a grain of salt. They are selling a front upgrade though. Girodisc (not bigger but better than stock) is a ways out from releasing an iron brake rotor conversion for the rears. Probably EOY or first quarter. CCB to iron conversion is just as far but I don’t know this for a fact. Just based off of what I heard.

There really isn’t much for these cars. I didn’t realize it took this long to get aftermarket parts out since I’ve had mine since early 21, but it has and it’s the name of the game. I think F80 buyers went through the same timelines etc.

When I last spoke with Girodisc, they said they were expecting end of the summer for the rears, so there's a bit of hope there. It's not a big brake kit though, so yeah not much as far as those go unfortunately. The stock rotors have been pretty good to me so far, unlike the stock pads which disintegrated at Laguna Seca 😂

[BMWRacer523]

Yeah not much in the way of bbk for this platform yet. AP is likely going to be first to market with one.

[shwayne5]

Originally Posted by ember.m4

When I last spoke with Girodisc, they said they were expecting end of the summer for the rears, so there's a bit of hope there. It's not a big brake kit though, so yeah not much as far as those go unfortunately. The stock rotors have been pretty good to me so far, unlike the stock pads which disintegrated at Laguna Seca 😂

From girodisc from 7/24/2023

“We’re still in the process of validating our new casting that we’re using to manufacture these and unfortunately our first production run of that casting is likely 12-14 weeks out”


So that puts that into October IF everything goes as planned. And just based on how most of these things go, I’m guessing there will be delays. Also, while the front Girodisc rotors are available on their website at this point, they show a delay of 1-3 weeks and I ordered mine on the 16th and they still have not shipped. So I’m still thinking post Christmas deliveries. AP may have their full rear BBK before then but those are definitely more a dedicated track setup.