Improving brake "feel"

[Dolemite]

This is a subjective question with no objective "answer," but I can confidently say that the brakes on my old BMW E46 felt awesome compared to the brakes in my P3D-. I would've done something about it by now were it not for regen.

I've heard that pads are mostly what's responsible for brake "feel," but I'd imagine rotor & caliper size also have an impact? I've installed the MPP brace, which helps a bit, but the brakes just don't feel as "bitey" as my old BMW, which did have fairly oversized brakes - the fronts were actually larger than those on my P3D-, despite the car being ~700 lbs lighter (all I needed was pads + fluid to run all day @ VIR).

Part of me worries that it's a result of not having a traditional brake booster setup... I hope that's not the case. Would be great to hear some thoughts from people who've played around with various setups. The different combinations I'm specifically curious about, in relation to each other, are:

OEM standard brakes
OEM Performance brakes
OEM standard + MPP Page Mill rotors
OEM Performance + MPP Page Mill rotors
MPP.R StopTech BBK

@MountainPass

Also pls let's not turn this into a "bigger brakes != shorting stopping distance" debate. pls.

 

[Ravire]

I have the mpp brace, mpp track front pads, and with ss lines and upgraded fluid. I feel better initial bite but you still have to put a lot of pressure on the pedal to get decent braking force.

 

[holmgang]

the opposite of bite feel is spongy feel, right? you press down, and you press harder, and it doesnt respond linearly. that could be flex in the cylinder - you've already fixed. that could be flex in the brake liner (expansion) - which you need something like SS. and if it occurs after heavy use, could be boiling of fluid.

so those are 3 easy and obvious things to try, 2 of which you havent

 

[Dolemite]

I have the mpp brace, mpp track front pads, and with ss lines and upgraded fluid. I feel better initial bite but you still have to put a lot of pressure on the pedal to get decent braking force.

Same - I guess to the extent that I can describe it "objectively" - that's one of the things I've noticed. Makes me feel like I'm just waiting for a sudden lock-up.

the opposite of bite feel is spongy feel, right? you press down, and you press harder, and it doesnt respond linearly. that could be flex in the cylinder - you've already fixed. that could be flex in the brake liner (expansion) - which you need something like SS. and if it occurs after heavy use, could be boiling of fluid.

so those are 3 easy and obvious things to try, 2 of which you havent

This is just day-to-day occasional "spirited driving." I had SS lines on my BMW - never really knew whether they resulted in any improvements. Raging debate on the internets on the subject, but if I end up upgrading brakes, I'll install them, just because.

I guess the main question is whether increasing the rotor circumference & installing phat-azz calipers would get the "feel" I'm looking for. If I do all of the above and it's still not there, I guess the only thing left to do is sulk.

 

[Zcd1]

Same - I guess to the extent that I can describe it "objectively"...

I guess the main question is whether increasing the rotor circumference & installing phat-azz calipers would get the "feel" I'm looking for. If I do all of the above and it's still not there, I guess the only thing left to do is sulk.

Don't you mean "subjectively"?

Personally, I've never thought the Model 3P's brake feel was lacking. It's subjectively better than my last 2 Audis in that respect, (including the S6 which had enormous rotors and calipers) and FAR better than my wife's SUV.

Objectively, it stops as well or better than its competitors (70-0 in 149 feet according to Car and Driver)

Maybe what you're actually feeling is how much force it takes to stop a car that weighs 4100+ pounds?

 

[Dolemite]

Don't you mean "subjectively"?

Personally, I've never thought the Model 3P's brake feel was lacking. It's subjectively better than my last 2 Audis in that respect, (including the S6 which had enormous rotors and calipers) and FAR better than my wife's SUV.

Objectively, it stops as well or better than its competitors (70-0 in 149 feet according to Car and Driver)

Maybe what you're actually feeling is how much force it takes to stop a car that weighs 4100+ pounds?

Well mine's a P-

And no I meant objectively because I'm certain I have to push the pedal harder on my P3D to achieve the same thing as my old E46. Unless I'm a lot weaker than I was back then. Which is possible because during COVID, when faced with "should I go to the gym?" or "should I drink 5 beers in the middle of the week?" I often choose the latter. Maybe what I need is a P+ setup?

 

[mattack4000]

The pedal is crap on the P+ too.

 

[Zcd1]

Well mine's a P-

And no I meant objectively because I'm certain I have to push the pedal harder on my P3D to achieve the same thing as my old E46. Unless I'm a lot weaker than I was back then. Which is possible because during COVID, when faced with "should I go to the gym?" or "should I drink 5 beers in the middle of the week?" I often choose the latter. Maybe what I need is a P+ setup?

Ah, that's an important distinction, and one I'm sure makes a significant difference in brake feel.

You've basically got brakes that are "just ok" for a 3800-lb. 350HP car trying to stop a 4100-lb. 550HP car - no surprise (to me) that they wouldn't feel good doing that or that they'd need lots of pedal pressure to achieve good stopping force...

Your E46 was at least 600 lbs. lighter, and even though it had BMW brakes (not known for being outstanding) they were probably "more than ok" for a vehicle of its weight and power...

 

[Dolemite]

Ah, that's an important distinction, and one I'm sure makes a significant difference in brake feel.

You've basically got brakes that are "just ok" for a 3800-lb. 350HP car trying to stop a 4100-lb. 550HP car - no surprise (to me) that they wouldn't feel good doing that or that they'd need lots of pedal pressure to achieve good stopping force...

Your E46 was at least 600 lbs. lighter, and even though it had BMW brakes (not known for being outstanding) they were probably "more than ok" for a vehicle of its weight and power...

Yeah the brakes on that thing were by far my favorite thing about it. And now with my summer set on my P3D- (265/35 19" PS4Ss) I can mash on the pedal really hard & the car continues to slow down without drama, it just feels like everything between my foot & the tires is trying REALLY hard.

I think it would make sense that increasing the overall circumference of the rotor should increase the "leverage" of the caliper, all else being equal. But I dunno. Waiting for others on here w/ toys to chime in.

 

[kilpatds]

IME, "bitey" feel came more from pads than calipers/rotors. Linearity came from brake components...

(Experience based on too many track days with a 1998 corvette, and modifying same)


Edit: history of that corvette
* stock brakes. Boiled like mad... I'm not gentle enough on the brakes, apparently.
* Replaced fluid with the blue stuff. Still boiled like mad.
* stainless steel brake lines. No change.
* Replaced pads. Feel got super "bitey", and I loved the feel. Still boiled like mad.
* Motul. Stopped boiling, had good feel. Had to replace the fluid every track day anyway or it would boil on the 2nd track day.
* BBK off a porsche turbo of the era. No boiling, went back to super-blue and a reasonable change interval. Used stock pads, and they were never as bitey as the more aggressive pads I had been using. ABS stopped working effectively when it was icy out.

 

[Zcd1]

Yeah the brakes on that thing were by far my favorite thing about it. And now with my summer set on my P3D- (265/35 19" PS4Ss) I can mash on the pedal really hard & the car continues to slow down without drama, it just feels like everything between my foot & the brakes is trying REALLY hard.

I think it would make sense that increasing the overall circumference of the rotor should increase the "leverage" of the caliper, all else being equal. But I dunno. Waiting for others on here w/ toys to chime in.

Rotor diameter is one factor, the stiffness of the caliper is another. No doubt that the Brembo calipers on the P3+ are stiffer than those on your car, so they don't flex (as much) under extreme use.

 

[dance.parrot]

When I first got the car (Performance), I thought the stock brakes were OK. Nothing extraordinary, but nothing to complain about either. After a visit to the track (2 sessions of 15 minutes), they became the worst brakes I ever experienced, most likely due to glazing. I did add the MPP brace, but could not feel a difference.

Switched to XP12 pads, and the feeling improved. On the street, they were OK. At the track, if it were not for the inadequate cooling, I would have been perfectly happy with the feel and stopping power.

A week ago, I got the MPP BBK installed, with XP20 front and XP12 back. During the bedding, and shortly after, they felt great. Now, after driving them a bit more, they feel good, although not out-of-this-world amazing.

I think a few things are at play here:
- The car is heavy (like other have mentioned)
- The instant acceleration is probably messing with your senses, and makes you expect equally violent braking with a similar pedal effort
- The standard regen mode is likely also detrimental to the brake feel. The car is already braking when you lift of the accelerator, so your baseline is shifted. During the bedding, in Track Mode with 0 regen, when I lifted off the brakes, it felt like the car was accelerating for an instant. I know that's not possible, but that's just what I felt.

I'm not sure how much the Stoptech calipers affect the brake feel for street driving. I'd like to convince myself that they do, but I'm not really sure. That's not why I got them though.

As for the size, I get your point regarding the rotor circumference, but not sure how much impact that has. For the front pads size, the BBK pads surface is similar: the OEM performance pads are 130mm x 62.6 mm (81 cm2) whereas the XP20 pads for Stoptech ST-60 are 151mm x 53 mm (80 cm2). As a note, the Stoptech street pads for ST-60 are 1 mm smaller on each axis, with a surface of 78 cm2 - I did not even bother to get put these on.

 

[Mash]

The size of pads is irrelevant. Larger rotors too. Shifting calipers out is really too small a change.
Change pads to the highest friction compound you can get at street temperatures and it will be better.
I'm certain that what you feel is a low friction compound.

 

[Zcd1]

The size of pads is irrelevant. Larger rotors too. Shifting calipers out is really too small a change.
Change pads to the highest friction compound you can get at street temperatures and it will be better.
I'm certain that what you feel is a low friction compound.

A more aggressive pad compound can be a double-edged sword. The stock pads don't dust too badly, but more aggressive pads often do, which brings a whole other set of issues. That said, it would indeed be a relatively quick and inexpensive way to change (and hopefully improve) the bite and brake modulation.

Extra dust and rotor damage are possible side effects...

 

[Zcd1]

Edit: history of that corvette
* stock brakes. Boiled like mad... I'm not gentle enough on the brakes, apparently.
* Replaced fluid with the blue stuff. Still boiled like mad.
* stainless steel brake lines. No change.
* Replaced pads. Feel got super "bitey", and I loved the feel. Still boiled like mad.
* Motul. Stopped boiling, had good feel. Had to replace the fluid every track day anyway or it would boil on the 2nd track day.
* BBK off a porsche turbo of the era. No boiling, went back to super-blue and a reasonable change interval. Used stock pads, and they were never as bitey as the more aggressive pads I had been using. ABS stopped working effectively when it was icy out.

You discovered what most novice track drivers don't initially realize: Power and handling aren't generally street cars' weakest systems; brakes are. And it's not just lines, pads and fluid, but cooling (or should I say lack thereof) as well.

BTDT on boiling fluid. The closest thing to "boil proof" fluid is Castrol SRF, but even it can be boiled - ask me how I know

Porsche is the only manufacturer that consistently offers true track-capable braking systems on their cars. They cost BIG money, but they work! (both the brakes AND the cars)

 

[kilpatds]

Heck, I wouldn't even say the BBK I used (from a Porsche) was even that expensive. The up-front cost wasn't that high. I think my pad&rotor costs went down.. I went from changing rotors almost as frequently as I had to change pads and the pads only lasting 2 track days at best (when running the more aggressive pads, IIRC. But the OEM rotors were really inexpensive), to never having to change rotors and the pads lasting ~4 track days each.

I'm just assuming that if I can figure out how to charge the M3P and do track days, that I'll have to pony up for serious brake upgrades. $5k for a BBK just isn't that high.

 

[Ravire]

For anyone saying weight I had a 2020 S5 loaner which weighs around the same as the model 3 and we have a 2020 x5 and a 2019 s560 which both weigh more and they have far better braking feel.

 

[asian_xl]

went straight from P- silly 320mm brake to 400mm 6 pots, it stops very quick, but easily trigger abs

 

[Dangerous Fish]

The answer is better pads. Tesla OE pads are rubbish. In the UK several owners who will never go on track have changed to different pads and commented the bite and feel are then much better.

Changing to a BBK in itself also is unlikely to give you a dramatically better bite or feel as has been discussed in several threads before. That is assuming the caliper piston area is roughly similar to the OE calipers for the same master cylinder. If you change that ratio you're going to feel a difference in pedal effort required to achieve the same braking force.

Whatever brakes are fitted it is the pad/rotor interface which is the biggest factor here.

Putting track pads in a Model 3 used mainly on the street is not such as bad idea as regen braking reduces the amount of dust, wear and squeal you'll get when driving 'normally'.

 

[ngng]

The answer is better pads. Tesla OE pads are rubbish. In the UK several owners who will never go on track have changed to different pads and commented the bite and feel are then much better.

Changing to a BBK in itself also is unlikely to give you a dramatically better bite or feel as has been discussed in several threads before. That is assuming the caliper piston area is roughly similar to the OE calipers for the same master cylinder. If you change that ratio you're going to feel a difference in pedal effort required to achieve the same braking force.

Whatever brakes are fitted it is the pad/rotor interface which is the biggest factor here.

Putting track pads in a Model 3 used mainly on the street is not such as bad idea as regen braking reduces the amount of dust, wear and squeal you'll get when driving 'normally'.

track/race pads on street are a terrible idea. universally: they need heat to be effective. i would argue it's even more important here with regen, since when you DO need the brakes, they will not work. more dependant on the pad: some track compounds are caustic and will eat your wheel finish.