Rotors..

I'm with SRTTom on this one. You can't disregard the cool factor. That is 75% of the reason we own Challengers. Just remember, the more you slot and drill your rotors, the less stopping surface you have on them.

 

However, due to the performance potential of the car, maximizing the braking, not just the engine, is an intelligent move.

I can testify that they haul the car down from 175mph really smartly.

These cars aren't built to cater to the timid Milquetoast types. There are many cars one can buy that have plain, even unventilated rotors, if only on the rear brakes. There's the Prius, too. Maybe a moped. A bicycle. A skateboard.

Never got to 186mph (300km/h) yet but, hey, tomorrow is another day.

The ducts are functional for cooling the various fluids, as are the vents on the 1st gen Hellcat hoods. I can testify that that car was rock solid at 180mph. No sign of float or front-end lightness. The corners of the hood were not even lifting, and I was paying attention to that in addition to watching WAY in front of the car. I thought I would see SOME lifting on the front corners. Nope.

It is the steadiest car at speed I have ever had. My 1971 Satellite's front end was FLOATING at a mere 127mph. (half the aerodynamic forces due to the physics) Boy, was that steering wheel LIGHT. I could even tell the nose was higher as I drove.

Some owners buy them to actually USE them, not just arrive in them, and the science that went into them is appreciated and necessary.

 

Thank you for that display of lack of knowledge of how dynamic friction works.

Dynamic friction is a product of pressure overall against a surface divided by the surface area affected. 1 ton of braking pressure against an area that is 50 square inches produces the same dynamic friction as 1 ton of braking pressure against an area that is 100 square inches. It merely has double the friction per unit of surface area.

You don't WANT static friction in brakes. You want dynamic friction. It's why ABS was developed, to always keep the rotor turning, which optimizes braking effect. You want static friction (traction) where the tires meet the road, not where the brake pad meets the brake rotor. They are two completely different desired effects.

Porsche has for decades cross-drilled their brake rotors for the very reasons SRT Tom mentioned. They experienced no crisis in lack of braking ability, and, in fact, their superior brakes were another reason they won so many championships.

Slots are not as good as cross-drilling when it comes to maximum braking effort, but they are sure better than a plain, flat surface. Cross-drilling will often require a thicker brake cheek material for maximum rotor life, so that is one reason you don't see it on the average street car, as no one wants to pony up the extra material and mass to properly engineer a perforated rotor for their car.

I had cross-drilled and ventilated rotors on my Neon ACR and that thing was phenomenal at braking. I had carbon metallic pads, and they got grabbier as the brake application proceeded, with no increase in pedal effort. Truly wonderful brakes.

@SRT-Tom was right. There is not a single downside to having the slots in the rotors, and sufficient upsides that it is far more than justified. Not all need of maximum braking is from joy rides at 150-plus mph. Some of it is at lower speeds but on a steep downward incline where, too, heat buildup and surface interface evacuation both matter. Ironically, it can be at low speeds, high inclines, and heavy or long-lasting brake applications that slots and/or perforations come into their own, not just in Vanishing Point situations. The level of air cooling at lower speeds can be downright inadequate. It's why the heavier rotors, not the cutesy aftermarket lightweight rotors are so important, no matter how many cooling vanes they have in them.

Lightweight rotors may be cute and clever, (and O so marketable) but nothing can replace SHEER MASS when it comes to some heavy braking situations.

The last place on Earth you want to lose weight on your car is brake rotors and cross-drilling and slots help braking when it is needed the most, and that is often under normal conditions, not only from high-speed braking.

PS slots also help water escape from under the rotor/pad interface via steam outgassing. Perforated rotors are even better.

 

I found some of this interesting.

https://knowhow.napaonline.com/what...two,glazing and improving braking consistency.

 

All of these slotted and cross drilled rotors maybe fine but only if you drive at those speeds warranted for these brakes to stop the vehicle and the extra expense these special rotors cost. I know brakes are important but if you don't drive over 70 MPH or above there is no need for these extra duty rotors for ME. It's great and fine if you can afford them and add an extra comfort of security because just because of the word BRAKES REDFLAG/SAFETY and function of stopping short if you drive at high speeds. But these are ultra performance so if you never use that potential of performance it's an extra added EXPENSE whether you use it or not. Like speed rated tires for 140 MPH V rated tires when the car can only go 115 MPH economy car or have tires that are capable of 176 MPH but you don't drive over 100 MPH in your regular commute noting that these tires wear out faster anyway even if you do drive like grandma because of softer rubber compounds.
Even more so if your driving style doesn't warrant sticky tires as you don't go around turns at 90 MPH+ miles.
We mention this because we get tired of spending all of this $$$$ on transportation on equipment on a car on items that we really don't use. We are feeling the effects and costs of inflation and higher costs of these products.
Sort of like well it be great to get a SPWB 392 but in actual usage a Challenger SXT V6 Penstar will fullfill most of MY needs and driving.

I do understand though the feeling is great that you have that 392 power with those Brembo brakes but when time comes you will pay more $$$$ (pay the piper for that equipment even though you may only use it a few times of driving your car in that manner).
You pay more for a car equipped that way just owning it to maintain it insure it, car payments etc.

We just come to realization after 45+ years of driving of the past high performance cars we have had that we really don't use all of the capabilities of that extra cost high performance engine, brakes etc.

But I know it feels great for those FEW times that you do open up this 392 MONSTER and hit those brakes knowing they have a real specific purpose and did the job to save your ass that ONE time you hit those FELONY DRIVING SPEEDS.
Bragging rights cost $$$$.
We are speaking only for ourselves and not saying this to all of you out there as we all have different driving styles and use our cars differently. Guess I am just getting tired of spending lots of $$$ with inflation not helping the situation.

 

I will reiterate the reasons why this is wrong again.

To re-reiterate: there are occasions available in everyday driving that warrant brakes with as much technology in them as possible.

To re-emphasize: There are times when heat buildup and attendant negative impact on the rotor-to-pad interface are deleterious to braking performance that can occur in EVERYDAY DRIVING, and it does not require high speeds.

The reason Lincoln-Mercury came up with special higher-boiling-temperature brake fluid for its cars, for example, was that it was found that many Lincoln drivers left-foot braked, and would drive around with their left foot RESTING on the brake pedal, leading to overheating of the brakes and the brake fluid, as a direct result.

Not all increases in brake capabilities are for high speeds or extremely rapid deceleration.

 

Not necessary on an economy car.

 

Depends on how you define an economy car. My Neon definitely found the ventilated and cross-drilled rotors to be VERY useful. Even the rear solid rotors were cross-drilled.
Not all economy cars are driven economically. My Neon lived its life pretty well at full throttle.

 

An economy car is my eyes is a car that gets 30+ miles per gallon, low maintenance, low cost to maintain, parts easy to get and afford, Reliable.

 

Well, the Neon WAS that, until I started driving it. But it was a Neon ACR. DESIGNED for just such shenanigans, if one was so inclined.