I have two Model 3’s (wife has LR RWD, I have P3D+) and the brakes react exactly the same. The big difference here are the bigger wheels on the P3D give it a wider turn and stiffer wheel while in Sports steering, but otherwise, they are nearly identical. I debadged my P3D so unless you see my calipers, you wouldn’t know I was a P3D.
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Questions About the Performance Model 3
- Thread starter mact3333
- Start date
Knightshade
Well-Known Member
They won't.
The brakes don't stop the car- the tires do.
Bigger brakes can never, ever stop the car shorter if the stock ones can engage ABS (which all new car brakes properly working have been able to do for many years now). The only thing they can do is help the brakes maintain the same stopping distance when you're making repeatedly high speed stops over and over without letting them cool (ie a race track, or the chase scene from a Jason Bourne movie)
If you want to stop shorter- get stickier tires (you can knock nearly 30 feet off your model 3 stopping distance from 60 just switching from OEM MXM4s to PS4S tires for example, otherwise identical wheels, brakes, etc)
If you'd like to understand the physics of this, and what upgrading each part of a braking system individually can, and can not do, I highly recommend this article-
GRM Pulp Friction
Author teaches SAE master classes on brake system design, has literally written books on topic, and designs braking systems for both OEM production use and race cars for folks like Ford, Stoptech, etc...
Good chance of that, but that will also risk making your other Tesla features not work (most likely) such as auto updates and Supercharging.
Msjulie
Active Member
Re tires stop the car not brakes, IF the ABS can be actuated.. true enough but I will say that I notice the different feel of the MPP rotors on my car even just on the street. I didn't even change the pads yet, will do be before Tesla Corsa though..
Knightshade
Well-Known Member
Yeah, tons of things can change the feel of the brakes... different pads, different rotors, even different brake lines or fluid... just none of em actually stop the car any shorter.
That Pulp Friction link I posted above does a nice job covering each individual brake system component and why, despite none of them reducing your stopping distance, a person might choose to replace any of them or not.... (and nearly every time the answer is one of or some combination of, "feel" or "heavy track use")
That Pulp Friction link I posted above does a nice job covering each individual brake system component and why, despite none of them reducing your stopping distance, a person might choose to replace any of them or not.... (and nearly every time the answer is one of or some combination of, "feel" or "heavy track use")
Msjulie
Active Member
Knightshade
Well-Known Member
Agreed given the caveat of activating ABS
Sure.. I just can't think of any modern car made in the last decade or more than can't already do that with stock factory brakes.
But if you're picking up a 54 DeSoto with drum brakes or something, by all means upgrade away!
I read that whole article and it's Fake News. Nowhere does it explain that the Performance brakes stop the car faster because they're Redder. Sheesh!
Agreed given the caveat of activating ABS
I don't quite agree with this. Mostly true, in simple terms, but not 100%.
The brakes can't stop the car faster than the tyres allow, BUT the whole brake/suspension/wheel/tyre system affects how much stopping force the tyre(s) can exert.
For one-thing, look at how weight transfer affects the braking. If you give it 100% braking, before the weight transfer, the wheels will lock (or ABS kicks in) and stopping distance increases. Match the braking to the weight transfer, and you can apply much more braking force and stop in a shorted distance, with the same tyres.
Changing the brakes affects that initial bite period, changing the way the brakes interact with the suspension/tires etc.
Changing the suspension affects the weight-transfer which affects the transition period, and the maximum force available.
Anyone ridden a motorbike will be intimately aware of how the brakes/suspension/tyres all interact to affect the braking performance. Especially at the limit.
Cars don't have the same degree of dynamic behavior, BUT it's not negligible.
Msjulie
Active Member
@Paddy3101 Yep, I just didn't want to get into a whole thing - I think my car brakes much better with the new rotors, as example, I like the feel better and they seem more responsive to me... I've had moments like that when I've changed brake pads as well. End of day, simplistic thing always comes back to tires, not brakes, stopping the car. Sure. But brakes stop the wheels so... yep
Knightshade
Well-Known Member
But brake bias is already tuned for that, from the factory, by the manufacturer for the stock braking system.
For a street car the factory tune is pretty much ideal, because you're going to be stopping in a lot of different conditions- so that tune gets you very close to "perfect" in the most conditions, and "safe" in all of them.
You can (and many do) actually make stopping distance WORSE by "upgrading" the brakes in a way that doesn't understand the factory bias... but you don't have much (safe) room to make it any better this way.
Consider this chart for example-
https://www.brakes-shop.com/media/wysiwyg/Content/brake-bias-7.jpg
Between OEM (which almost always front biased) to "optimally tuned" which is only very slightly less so, to "approaching unstable braking" which is again slightly less so, there's VERY little difference in actual stopping distance... but if you go significantly more in either direction braking distance (and stability especially moving toward rear bias) get significantly worse.
Now, if you're building a track car, that's only ever driven in specific known conditions, and braking in specific known ways, you can tune a little nearer the bleeding edge... but for "regular" use not so much.
As evidence I present basically every major aftermarket brake manufacturer, who if their "big brake kits" could actually, safely, reliably, and measurably stop your car shorter in normal use would be screaming such from the rooftops.
Instead folks like Stoptech and Brembo are actually fairly honest about this and clearly tell you no, your car won't stop any shorter than with factory brakes with their upgraded brakes on the vehicle in street conditions.... (though stoptech in particular has a whitepaper about how upgrades can actually make your braking worse if you upgrade kit isn't considering proper proportioning to match what the factory ABS system is expecting).
Funny story though- the author of the GRM Pulp Friction article addresses your exact concern in a follow-up article....
Brake Bias And Performance
He's basically saying same as I am above, but with lots more math and physics if interested.... and giving pointers too to those who are only tracking the car in very specific conditions about how they might go about chasing down that extra 0.5% of bias benefit for those conditions.
He also later mentions that if you add ABS to the equation this is even less a factor and there's even less of a fringe of a difference to try and do anything about, especially on a street vehicle, to the point all you're really gaining even way out at the bleeding edge is reducing wear for ABS cycling, not really stopping shorter.
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