[Tengocity]

Originally Posted by NISFAN

I'm not sure I agree with that....the co-efficient of friction between tyre and road is the same at 60 as it is at 80 or even 150 for that matter. Therefore the brake force required to exceed friction is the same regardless of speed.....unless you are talking about a car with downforce (road cars have lift at speed, so should in theory be even easier to lock the brakes at high speeds).

What can have a high speed braking effect, is the brakes overheating within one stopping event. Won't happen at 60, but could from high speeds like 120mph. This is also the issue on track, where the standard brakes don't have the ability to 'recover' in heat between corners, where a BBK should have more capacity to do so, and builds less heat in each braking event in the first place.

Not sure it's even as simple as any of us are trying to make it sound... whilst the level of friction may be the same it's clearly much easier to lock wheels up at a low speed than a high speed, all else being equal, if for no other reason than they're rotating much much faster so locking them is going to be incredibly difficult without an extremely powerful clamping force.

[teaston]

Originally Posted by NISFAN

I'm not sure I agree with that....the co-efficient of friction between tyre and road is the same at 60 as it is at 80 or even 150 for that matter. Therefore the brake force required to exceed friction is the same regardless of speed.....unless you are talking about a car with downforce (road cars have lift at speed, so should in theory be even easier to lock the brakes at high speeds).

What can have a high speed braking effect, is the brakes overheating within one stopping event. Won't happen at 60, but could from high speeds like 120mph. This is also the issue on track, where the standard brakes don't have the ability to 'recover' in heat between corners, where a BBK should have more capacity to do so, and builds less heat in each braking event in the first place.

Coefficient of friction between tyre and road may be the same at higher speed, but the rotational force (torque) created is higher, so therefore requires a stronger stopping force to reduce the wheel rotation speed.

[NISFAN]

Originally Posted by teaston

Coefficient of friction between tyre and road may be the same at higher speed, but the rotational force (torque) created is higher, so therefore requires a stronger stopping force to reduce the wheel rotation speed.

Sure, but in the context of stopping 1.7 tons of speeding metal, the extra inertial forces of 30-40Kg's of rotating mass is minimal. See how quick a bicycle wheel stops when spinning in free air, it's almost instant.

[teaston]

Originally Posted by NISFAN

Sure, but in the context of stopping 1.7 tons of speeding metal, the extra inertial forces of 30-40Kg's of rotating mass is minimal. See how quick a bicycle wheel stops when spinning in free air, it's almost instant.

Yes but there're not just stopping a moving object, they're also slowing down a spinning mass. The faster a mass spins, the higher it's effective weight, so the larger inertial force it requires to slow it.

Inertial force explained here by someone far more intelligent than me:

http://www.school-for-champions.com/...m#.WQc8I4HTXYU

[CazuaLLUK]

Originally Posted by teaston

Possibly why CazuaLLUK doesn't think his retroftted M Sport brakes are any better than the originals!?

Day to day driving though, you would never know really.

I'd love to take this car somewhere to push its limits and then maybe yeah I would see a difference.

[VR 46 Fan]

Wow, thanks for all these comments, really learning lots. Perhaps I have not got used to the way the car behaves yet, I have only had it two or three weeks. My previous car a 123d I had for several years and I got to know exactly what it would do. I haven't started to drive the 330 hard yet, will be able to make a better judgement then.
Again, thanks for all the information, brilliant.

[Watsey]

There are a lot of forces and variables operating on the car and these are not constant as speed changes.

As speed increases the total energy transferred into the vehicle rises (non-linear; I'd guess by the square of the speed) so the braking system has a huge amount of work to do as speed increases. The components in a big brake system provide several benefits : larger diameter discs provide greater retardation for a fixed pad area and pressure; larger pad area and higher performance pad material increases the friction coefficient and ability to perform at higher temperatures; thicker ventilated discs and (with the StopTechs) swept internal vanes provide greater air through flow and cooling.

Tyre/road friction coefficient does not remain constant with speed, once the effect of weight-transference under braking is factored-in. Hence why BBKs are often sold for the front only.

I find the most noticeable improvements to be brake feel, greater progression and control due to the improved performance, and (so far, on the road) no fade. High performance pads in an MPerformance setup may perform very well, but I didn't go down that route.

I've found that better pads (EBC Yellow Stuff) provided incrementally improved performance. The StopTech BBK improves the performance by an order of magnitude.

[rossm]

Originally Posted by Tengocity

Exactly, but more like 30mph if it's wet with standard brakes!

The other quality that you'd want from a braking system is "feel", so that you can tell when the wheels are going to start locking up.

The reality is 99% of drivers have no idea how to get the most out of their brakes and don't press the pedal nearly hard enough in an emergency braking situation. If you look at the telemetry of a pro racing driver and even someone with track day experience, in the same car, the braking force the pro puts trough the brakes is much higher (also much later too).

We can test this if you like, side by side on the A34 - you should be able to consistently pull up measurably shorter each time with your big brake kit over my standard setup. £20 quid says no difference

Reaction times would have to be ruled out though, so we'd need to choose some fixed points of reference

[Tengocity]

Originally Posted by rossm

We can test this if you like, side by side on the A34 - you should be able to consistently pull up measurably shorter each time with your big brake kit over my standard setup. £20 quid says no difference

Reaction times would have to be ruled out though, so we'd need to choose some fixed points of reference

Anytime you like Ross. Having driven my car over 90k miles wth standard brakes, upgraded pads, and a BBK, I'm pretty sure about how much extra braking there is available to me now.

Depending on the speed at which we start braking too, the test will only be repeatable a few times too for yourself before it's a test of braking endurance.

The other factor is I'm now running PS4S tyres and I'm pretty they will up the level of braking force which can be applied.

[Tengocity]

Originally Posted by Tengocity

Anytime you like Ross. Having driven my car over 90k miles wth standard brakes, upgraded pads, and a BBK, I'm pretty sure about how much extra braking there is available to me now.

Depending on the speed at which we start braking too, the test will only be repeatable a few times too for yourself before it's a test of braking endurance.

The other factor is I'm now running PS4S tyres and I'm pretty they will up the level of braking force which can be applied.

I've just realised you may be claiming that your braking technique is better rather mine, rather than a bbk is not really any better, in which case feel free to have a drive of my car yourself to decide. I've no interest in trying to prove driving skills on the public road.

[rossm]

Not interested in technique, we can all stand on a brake pedal with the same amount of force Purely interested in the shorter stopping distance a BBK gives you

[Tengocity]

Originally Posted by rossm

Not interested in technique, we can all stand on a brake pedal with the same amount of force Purely interested in the shorter stopping distance a BBK gives you

Well that's not true either, though I make no claim on my own braking technique, as I know it could be improved considerably on track days. Probably safer if you fancy taking my car out and trying the brakes for yourself.

[rossm]

Thanks, that's a generous offer but that wouldn't tell me how many metres shorter stopping distance at x/y/z given speed etc. Pedal feel doesn't equate to stopping distance