S650 Brakes

[abstruse1]

Also…





If the stock system isn’t a limiting factor:

• Then the brakes already generate enough force to trigger ABS under hard braking, meaning the tires are skidding (controlled by ABS).
• In that case, adding larger discs won’t stop you faster, because the tires are already doing all they can.
• 
  

• Abs doesn’t lock and hold it grabs and releases (repeatedly quickly - hence why with abs we don’t pump the brakes), surface area plays a part in the effectiveness of the ‘grab’

  Zig may be right. I don’t know enough to comment further on this.

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[abstruse1]

This theoretical discussion seems never ending. I expect some laboratory has done tests, but I don’t know of any. Does anyone have actual, measurable experience in braking performance by enlarging rotors?
never mind the feel of the brake pedal, I mean the absolute stopping distance

my previous comments have exempted race track performance on the basis of the ability of larger rotor to dump heat. I suppose it’s possible that even on ordinary highway circumstances (e.g. 70 mph) or around town circumstance (e.g. 40 mph) with a cold rotor, the rotor heats up enough to start diminishing breaking performance.

I should communicate with Brembo and other such companies to get their explanation.

 

[abstruse1]

Wilwood says:

Most modern stock brake systems work well for average daily street driving and an occasional 60-0 or 80-0 stopping. Typically performance enthusiasts, who occasionally compete in racing events, push the stock brake system beyond its capabilities. Driving style, and other performance modifications such as increased horsepower, tire and suspension upgrades, etc., can quickly overwhelm stock brakes. A Wilwood Big Brake kit will provide a number of benefits. Some benefits include increased heat capacity, which means substantially more resistance to brake fade and caliper distortion with multiple stops from high speed. Stronger and stiffer components offer a firmer pedal with the ability to better modulate the brakes consistently.

=============
Wilwood does not claim that their products will increase braking performance under ordinary, non-racing circumstances. In fact, the first sentence of their reply seems to admit that the contrary is true, even given the obvious bias of the company selling the big brakes. This seems pretty convincing.

Big fancy brakes look great. They must be, because all the racers use them, right? But I’m afraid that many street drivers fall for this line without looking at actual braking numbers. We do a lot of things to our cars, just for appearance, to which I have no objection. If someone wants to believe that X is the case, that’s fine with me. But please don’t tell me that there’s any evidence to back this up and that it’s more than personal indulgence.

EMDW.

Let the flames begin!

 

[Zig]

Wilwood says:

Most modern stock brake systems work well for average daily street driving and an occasional 60-0 or 80-0 stopping. Typically performance enthusiasts, who occasionally compete in racing events, push the stock brake system beyond its capabilities. Driving style, and other performance modifications such as increased horsepower, tire and suspension upgrades, etc., can quickly overwhelm stock brakes. A Wilwood Big Brake kit will provide a number of benefits. Some benefits include increased heat capacity, which means substantially more resistance to brake fade and caliper distortion with multiple stops from high speed. Stronger and stiffer components offer a firmer pedal with the ability to better modulate the brakes consistently.

=============
Wilwood does not claim that their products will increase braking performance under ordinary, non-racing circumstances. In fact, the first sentence of their reply seems to admit that the contrary is true, even given the obvious bias of the company selling the big brakes. This seems pretty convincing.

Big fancy brakes look great. They must be, because all the racers use them, right? But I’m afraid that many street drivers fall for this line without looking at actual braking numbers. We do a lot of things to our cars, just for appearance, to which I have no objection. If someone wants to believe that X is the case, that’s fine with me. But please don’t tell me that there’s any evidence to back this up and that it’s more than personal indulgence.

EMDW.

Let the flames begin!

Graceful stopping is hardly an emergency. Individual components usually don’t provide the same results as a complete system.

 

[Zig]

My car has the basic brakes. I wonder if there's any way to reduce stopping distance on the streets, with brakes that are not really hot.

Engine braking

 

[abstruse1]

Abs doesn’t lock and hold it grabs and releases (repeatedly quickly - hence why with abs we don’t pump the brakes), surface area plays a part in the effectiveness of the ‘grab’

I don't know enough about the functioning of ABS to comment on this.

Enough (for me, anyway) on this thread.

Thanx, guys.

 

[erocker]

This isn't difficult. Just looks a 60-0 tests.

 

[Junkyard Dog]

They have the same brakes though? The DH has wider wheels and tyres to make better use of the brakes.

I am not entirely certain what you mean by "they," but if you are discussing the GT performance pack and the Dark Horse handling package, they are not the same brakes. The Dark Horse has 15.4" rotors. I believe that the rear rotors are larger, too. Magneride is standard, and, of course, the tires. The entire package is what brings this heavy beast to a stop in such an unbelievably short distance.

 

[Cz_Ziemniak]

I don't know enough about the functioning of ABS to comment on this.

Enough (for me, anyway) on this thread.

Thanx, guys.

ABS Units pulse pressure to individual wheels based on signals from a reluctor wheel/ring at each hub. This ring also measures wheel speed in many cases, hence why losing a wheel speed sensor often means no ABS, as there's no signal to the unit from that corner of the car.

If the difference at the reluctor ring indicates wheel slip, the ABS unit simply opens and closes the fluid flow to that individual wheel. Thats the overly simplified explanation.

Below is a reluctor ring. Think of each flat representing a 1, while the valley's represent a 0. Based on the speed of these spinning around and getting picked up by a sensor, wheel speed is able to be determined, as well as slip based on the relation to all other wheels. I Believe modern ABS systems also take into consideration a bunch of other shit like gyroscope readings, etc, but all of that is beyond my understanding of how it all gets read by the car and computed.

Hope all that sorta makes sense

 

[krisk]

I am not entirely certain what you mean by "they," but if you are discussing the GT performance pack and the Dark Horse handling package, they are not the same brakes. The Dark Horse has 15.4" rotors. I believe that the rear rotors are larger, too. Magneride is standard, and, of course, the tires. The entire package is what brings this heavy beast to a stop in such an unbelievably short distance.

The Dark Horse and GT PP have the same brakes. The only difference is the DH has two piece front rotors. The DH and GT PP rotors are the same size and interchangeable.

 

[LouG]

I understand that larger discs increase leverage, but does that matter? It seems like if you could lock the tires up with a smaller disc then you have plenty of leverage and it’s all up to the ABS after that point.

It does matter in the real world. If you can stop with less pedal pressure you'll be able to modulate the brakes more effectively. Braking at the point of ABS intervention is more effective than just stomping on the pedal.
Even though ABS is modulating fluid pressure, the applying and releasing of the brakes does increase stopping distance in the dry slightly.
F1 cars do not use ABS. The aliens that drive them have skills beyond we mortals.

 

[LouG]

The Dark Horse and GT PP have the same brakes. The only difference is the DH has two piece front rotors. The DH and GT PP rotors are the same size and interchangeable.

Thanks. That's what I thought.

 

[krisk]

It does matter in the real world. If you can stop with less pedal pressure you'll be able to modulate the brakes more effectively. Braking at the point of ABS intervention is more effective than just stomping on the pedal.
Even though ABS is modulating fluid pressure, the applying and releasing of the brakes does increase stopping distance in the dry slightly.
F1 cars do not use ABS. The aliens that drive them have skills beyond we mortals.

This is accurate. Braking at the threshold of locking the brakes or ABS kicking in will give a shorter stopping distance than just stomping them and relying on ABS or skidding. In everyday driving I would venture to say for 99% of people, having the bigger brakes wouldn’t make a difference in an emergency as they are going to stomp them as hard as possible. This is because they aren’t used to finding the limit of the brakes where it is second nature like an F1 driver. So, bigger brakes will stop better, but I’d say in the vast majority of emergency stops it’s going to make very little difference. On the track is a completely different story and it makes a huge difference. Disclaimer: I’m not an expert, but I did stay at a Holiday Inn last night.

 

[Junkyard Dog]

The Dark Horse and GT PP have the same brakes. The only difference is the DH has two piece front rotors. The DH and GT PP rotors are the same size and interchangeable.

Thanks. That's what I thought.

Thanks - Google gave me the S550 15 inch spec . . .

 

[Sofa King]

The Dark Horse and GT PP have the same brakes. The only difference is the DH has two piece front rotors. The DH and GT PP rotors are the same size and interchangeable.

Yep... even the Ecoboost with HPP (only 24 MY) has the same brakes as well.

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