babber

Right, I just got to get this off my chest!!

I've got an RB5 WR and brakes were in serious need of replacing. I looked around and was seriously considering getting some nice shiny new Brenbos or AP / Pro-drive six pots, etc.

A good mate of mine suggested that this would be a complete waste of money, as the limiting factor on my car would be the ABS system (ie the ABS system will work long before the standard brakes full potential could be reached) :rolleyes2:

In light of this I bought OEM disks (from a motor factor) and Ian Godspeed very kindly grooved them for me, and supplied me with up-rated pads.

Fitted them along with nice shiny new disks on the back (also supplied by Godspeed, but weren't really needed) and Apec pads (nice and cheap, less than a tenner)

Been bedding the brakes in for a few weeks now, and am very pleased with the results.

Got to be said though and I know a hell of a lot of people won't like it.............. But if I stand on the brakes (dry or wet) I can feel the ABS working on the fronts brakes. Question is, how the hell can bigger / stronger brakes be of any kind of benefit to you?

I've done a few track days and never really had any fade, so why do people spend pots of money on up-rated brakes, other than for eye candy?

Please explain, as I don't understand ? I'm not try to start a war here, but I guess a few people will get there head up there asses over this thread

Thanks Phill

RON

i don't quite understand the physics involved, but i have Ian's 335mm kit on mine, and unless i'm really silly, the ABS doesn't ever cut in, i have been on track for serious amounts of time, and have never had fade, or ABS......

Brit_in_Japan

Kinetic energy is proportional to the square of the velocity. What that means for example is that the brake have to dissipate about 30% more energy braking to zero from 80mph than they have to from 70mph.

Assuming you don't lock the wheels up (i.e. ABS, as you've stated) then all that energy has to be dissipated by the brakes. Above a certain temperature conventional brake materials stop functioning correctly and you get brake fade, so one benefit of uprating brakes is to have larger brake pads (with 4 pot or 6 pot brake calipers to even out the force applied to the pads) so that the same energy is spread over a greater area of pad, with more chance to disspate heat energy, thus resulting in lower pad temperatures and resistance to fade.

Also larger disks mean that the braking torque which can be applied to the wheels is increased (you have an increased leverage), which means that so long as you have sufficient traction between tyre and road, you can apply more braking force and decelerate more quickly.

So large disks means greater retardation force can be applied (so long as you have sufficient traction, little use on wet roads or snow etc) and large pads mean better heat disspiation and therefore more resistance to fade. So on dry tarmac with good tyres you would expect braking performance to be better with large disks and larger pads. Of course there are other factors involved, such as brake material, vented/slotted disks, brake fluid etc.

D1CCY

Just changed my OE Brembos to AP 6 pots. The brake pedal feel is fabulously progressive/controllable and worth the expense on its own. I suspect this has more to do with the quality of the engineering rather than the physics but worth consideration when making brake choice.

Sadly I have to admit this was originally an eye candy decision but I've been very pleasantly surprised with the result and had I known how good they feel I'd have done this sooner.

ozzy

I surprised RON that you've never had ABS kick in. Perhaps this is simply down to your tyres and road surface. I've had my ABS kick in (perhaps on slightly) with both Ian's 335mm upgrade, std discs/pads and with my current EBC setup.