Thread: Brakes are too heavy

Nonsense.

Horsepower is a very indirect consideration. It's not horsepower that needs to be shed, it's velocity. Things more important than hp would be weight, tires and how frequently the brakes are being applied in a given timeframe (ie. how much heat they're going to see). Other items would be suspension, alignment setup, aero downforce, etc. And before you say it, yes hp can be converted into velocity, but the key word there is "can". It doesn't mean it will. There's a whole bunch of other things that need to happen first. Especially, when you're talkin road course.

Take my car for example. With my (7 year old, used at 3 conventions) set of Kumho MX's, I could up the power to 650hp and still be fine with my AD22/Axxis Ultimate setup. Why? Because the tires are only going to provide me with so much deceleration before they lock. They're not going to produce the kind of heat that warrants a big whompin BBK setup. The tires are also going to drastically limit my velocity going around the track (ie lateral grip and acceleration). So in effect, that 650 hp is not being converted to velocity. To my point, HP is not the gauge that should be used in determining brake selection. There's way more to it than that.

The other big considerartion is modulation. In a lot of cases, huge high friction brakes make it damn near impossible to modulate at or near threshold. Especially so, in our relatively lightweight rust cans. Flat spotted tires, anyone?

IMO, the best braking mod one can do to their car is to buy stickier tires and then select a pad with the appropriate friction level/heat range. When shit starts to melt and/or fade, then, and only then, is it time for bigger metal.

The issue won't be "warping". The issue is going to be fading from overheating the pad/caliper out of their heat range. If anything, the rotor will crack and sometimes shatter. That usually happens on an set that has a few heat cycles on them and then are pushed too hard. The whole idea for bigger caliper/rotors is to shed heat at a faster rate. There is such a thing as too much, as you've mentioned.

Assuming you're not well outside the realm of sanity when it comes to a well rounded track car, horsepower will be the main factor in deciding braking needs. You're close that velocity needs to be shed, but it is momentum that needs to be shed, so we're including speed and weight of the vehicle. Basically, you want to take momentous energy out of the system with the brakes and turn it into heat energy. How did the momentous energy get there in the first place, and how much of it do you have to shed by the time you get to the corner? The engine put it there, and there will be a certain amount of energy in the system based on how much power the engine has (and how long it was applied). How much engine you have should determine how much brake you need. Assuming some sort of sane envelope.
Sure, if you have very little traction you won't be able to put energy into the system with the engine regardless of power, but I'm trying to keep things relevant here.

...and none of the above matters if the track configuration doesn't tax the braking components.

I'll turn AD22VF rotors rainbow colors with stock horsepower at Hallett (straights terminating in repeated downhill braking runs), but on AD18s passed SR20VE cars at a wide momentum roval like Texas World Speedway.

Equip to the whole need.

Thats why is was thinkin on bigger rotors at least as the AD22 do the task i want something that can easely handle the track for lots of laps without fade.

I already have SS brake lines, Altima U13 MC, ATE blue racing DOT4 brake fluid, Ross Brake pads and the rear maximas.

If you must go larger than that, do one of the Fastbrakes kits with the aluminum calipers and maybe even aluminum rotor hats. You'll get better fade resistance and won't take on the unstrung weight or as much rotational inertia as the 3000GT setup..

I still think you're fine with the setup you have now though.

No one is wrong in their arguments but Hank is more right in his approach. Tires should come before massive brakes. If the tires suck everything else suffers.

Take the people that say that HP+ pads work decent on the track, I ran a set of HP+ as an experiment for a session at a track day. My car with 250 whp, 2325 total weight on 225 50 16 Hankook R compounds and the pads were shit! Completely useless and I was stopping 500- feet out in the heavy braking zones and could not lock the tires despite the fact that I had the big wildwood kit up front, Maximus in the back an the Altima MC.

Next session out I moved to Hawk DTC60 pads and finally I could push the car hard.

Just proof that things need to be designed as a total package rather than leaving on mediocre tires yet stepping to big boy brakes.

As an experienced TT driver that has always been moderately fast and competent on a road course take Hanks advice and design a brake package around suspension and tire selection first. Especially if you are NEW to the track.

Right, brake fade is the big issue on track day, which is his primary concern.

But if he drives this as a daily driver also, continued overheating can lead to warping of the rotors before it cracks them, right? and that will require replacement of the rotors before you can drive on the street without vibrating stops.


(note: I do not like turning rotors.. I had a perfectly good set of NX rotors, I replaced my pads and turned the rotors and only now does it vibrate when braking. the rotors were only a year old, they were well within spec to be turned, its just that you never know if the shop turning the rotors is doing it right and brand new rotors are usually straight & true.)

Brake rotors don't warp. But I'm not trying to start a discussion on that. :o

That is a good white paper for people to understand what is going on in braking. More often than not people have issues because they do not follow proper bedding procedures. Hell a good bed in is required on ALL brake jobs. I have done rotor and pad replacements for friends that KEPT having issues after the dealer resurfaced rotors and sent them on their way. They were amazed at how long their el cheapo parts store rotors and OEM pads lasted after I did them versus the dealer. The only difference was proper cleaning upon installation as well as bedding.

Regardless of what brake setup you choose bed them in properly or you will NOT be getting the performance or life out of them. On my first set of Rotors on my two piece fastbrakes setup I went through 4 sets of pads, completely removed ALL of the rotor slots through wear, and the rotors were STILL rock solid.