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Discussion in 'Model 3: Driving Dynamics' started by bradhs, Aug 12, 2018.
Has anyone tested the braking on a Performance 3 yet? I’m wondering how well it stops from 60 to 0.
The most interesting thing about the 60-0 deceleration time for any given tire setup is that it is pretty close to the 0-60 acceleration limits of the same tires, assuming the restrictions like motor torque and max power and battery current could be overcome.
As physics requires, it should be exactly the same as the non-P version of the same car on the same tires.
The brakes don't stop the car, the tires do.
The Road and Track article didn't publish the exact numbers, but it did mention the following:
"The braking is prodigious, too, with 60-0 and 80-0 distances on par with a BMW M3 on carbon ceramics."
Doesn't sound too shabby.
Check Forkees thread Dragy measures 60-0 as well ..and he had posted 0-60 so he prob has those numbers ...
True but the brakes need to be capable of leveraging the stopping capability of the tires.
which all cars stock brakes have been able to do from 60 (or any normal highway speed) for decades at this point.
It's why folks like Brembo tell you in their FAQ they don't even bother to offer 60-0 stats on their brake kits- since they make no actual difference to normal stopping distances compared to stock brakes on the same tires.
What "upgraded" brakes can do (if they're properly upgraded) is let he car maintain that same stopping distance over many repeated high speed stops without giving them a chance to cool down- which is useful on a race track, but not generally in 'real life' unless your name is Jason Bourne.
Why is that useful on a race track? How often do you need to come to a complete stop on a race track?
You don't need to come to a complete stop... Braking from 150 to 100 (or whatever lower speed you need to take a specific turn at), over and over, back to back to back, is when things like bigger rotors help as the can better handle the heat involved without fading. They still won't stop you shorter, but they'll keep you stopping the same for longer.
This is irrelevant in street use though- hence why testing 60-0 numbers of different factory brake setups on the same car with the tires gives you identical results.... (see for example the Porsche PCCB $10,000 brake upgrade that produces exactly the same 60-0 stopping distance as stock brakes)
I believe those cars stop in under 110ft, so that’s a big improvement.
A bit aged (June 2015) but perhaps useful for discussion:
Fast Brake: 20 Best 60 to 0 Distances Recorded by Motor Trend - Motor Trend
Another interesting read:
BMW M Carbon Ceramic Brakes - The Complete Guide
It seems impossible that the Model 3P will match those numbers since it's heavier AND has narrower tires than every car on that list.
Contact patch size (i.e., area) is a function primarily of weight and tire pressure, not tire width.
Given roughly equal tire pressure and weight, a narrower tire will have a more longitudinal contact patch, while a wider tire will have a more horizontal contact patch. The former theoretically is better for braking and acceleration, while the latter is better for cornering. (A reference: WIDER TIRE = BIGGER FOOTPRINT?)
Tire compound and braking dynamics (interaction of ABS for example) are likely to be a large factor, too.
So, even though the cars with wider tires are likely to out-perform the 3P in an all-around competition (i.e., one that involves cornering), it is not implausible that the 3P will match them in braking.
I guess we'll see when there are measured results. It seems odd that there are no heavy, narrow tired vehicles on that list.
Daniel please note in that entire BMW article, they do not mention shorter braking distance as an advantage of ceramic disks/brakes
Ceramic brakes do nothing for 60-0 braking distance. As far as I can tell the things that determine braking distance are:
Tire compound (Pilot Sport 4S are good tires, the BMW M3 comes with them too. The top cars on that list have even stickier tires)
Weight (Model 3 is heavy!)
Weight bias (rear weight bias helps. The Porsche 911 does very well in braking tests)
ABS algorithm (Maybe Tesla has managed to outdo everyone else?)
Theoretically it should be the same, but I find it hard to stop from 60 in 3.5 seconds comfortably
There are numbers that the dragy generated but they're not valid because I slowed down much slower than during acceleration, rather than slamming the brakes.
The Model 3 LR stops from 60mph in about 3 seconds (assuming constant acceleration) so the 3P should be faster with its stickier tires.
Slam on the brakes and see!
I only tried one full stop to see what it would do, dragy did not validate it as it was going downhill at 1.01% or just over the 1% limit for a valid test, RWD on sport wheels, plan on getting the Titan 7 from the group buy staggered with ps4 275/35/19 rear and 245/40/19 front, I'm pretty sure we should see under 120 ft maybe 115?
Interesting... that's actually worse than my S70D (on MXM4s) and the g-force graph looks a little weird.