ogvw

iTrader: (4)

Alcon info here STaSIS/Alcon Evo Brake info

x838nwy

Thank you for the link!!

Sticking with the effective = rotor diam. - (big pistion+11) guess

So with that, we have this:

Piston area/%brake torque compared to stock/f:r ratio
Alcon 328 = 56.26/100.22/2.48 (virtually stock)
Alcon 355 = 56.26/112.11/2.72
Alcon 370 = 56.26/117.61/2.85

I don't know what sort of wheel you'd need to stuff the 370mm rotor in, the rotor alone is 14.6" diameter, so I think you'd be pushing it even on 19" wheels.

Anyhow, they're light at 11.7/12.4/13.6kg respectively...

Now anyone for stoptech?

I really should get them all on the same list...

x838nwy

Just found Racing Brake's kits. Yes, this is what I do on a Saturday night.

Front
Piston area/%brake torque compared to stock
RB 6 piston 355 = 59.27/118.1

Rear
RB 4 piston 332 = 45.36(!!)/2.03(!!)

Using their Front ONLY f:r = 2.86
Using their Front & Rear f:r = ~1(!!!)

The data for the rear kit HAS to be wrong, but it came from their site: http://www.racingbrake.com/LANCER_EV...34-311-411.htm

Looks more like a front kit to me....
So, if it's a FRONT kit then it would be

RB 4 piston 332 = 45.36/83.6/2.03 f:r
Which is less silly but a bit useless compared to stock fronts.

termsheet

iTrader: (1)

This is interesting info. The reason that many manufacturers (Stop Tech, Brembo, AP) make mulitple rotor sizes is to allow for different wheel sizes. The other big benefit of these kits is that the rotors float and they are designed to dissipate heat. As for brake bias, it is easy enough to install bias adjustment. All race cars have this.

I warped my stock rotors after just a couple of track days. With Stop Techs in front and the stockers in the rear, the Evo now brakes like a different car. For how heavy the Evo is I'm impressed on how fast it will slow down. I would guess it is at least a 25% improvement over stock and they don't fade.

scorke

iTrader: (18)

Does anybody make a brake balance adjuster for our cars?

Scorke

dave12285

iTrader: (2)

Are you sure you warped the disc?
http://www.stoptech.com/tech_info/wp...rakedisk.shtml

x838nwy

You're right about the heat dissipation and wheel fitment.

But there are several problems with the bias thing:
1.) We don't all drive race cars, and not all race cars have them. You're not allowed them in some series/divisions.
2.) The bias adjuster (valve type) only really works if the original - hardware orientated - balance is fairly close.

As far as I'm aware, there are two types. a.)hydraulic type b.)mechanical type. Now I'm not going to talk about (b.) cos they mainly come in the form of a new pedal box and balance bar set. If you're going to have that then you'll need professional race engineers at which point you need to buy brakes in 'kits'. Just get the guy tell you what calipers and rotors you need.

Anyway, the hydraulic types look like a fairly non-descript valve, 4" tall and around 2" diameter and you fit it on the rear brake lines. The reason it only really works if the original hardware is close to what you want is that they aren't as flexible as their names suggest.

It's a bit long, but on a given proportioning valve, there are two ratios. These are ratios between the input pressure (from the master cyl) and output pressure (to the rear calipers). One of which is normally 1:1 and the other is usually fixed at 1:3 (or something fairly close). These ratios are fixed and that you do is select the point at which you want to go from one ratio to another. You always start with 1:1 and then when the input pressure go up to a point (say 30bar) the ratio between the input switches to 1:3 so when the pressure to the front is 30bar, it's als0 30bar to the rear but when the pressure to the front is say 40 bar, it's 30 +(10/3) = 33.33 to the rear. Obviously this is to counteract the weight transfer off the rear.

Now, if we're going to start off at 1:1 then our original ratio should be close to ideal. And really, it is pretty difficult to work out (without a LOT of data) where the switch point should be, specially on a road car where you have all sorts of conditions.

With a balance bar (type b), you can change the balance, but you will be only able to change it to one value - like 1:x and that's it. It will stay that way no matter how hard/gently you brake. That's okay for racing cars where most braking is done around max rate and you can change balance at each race/circuit and conditions. Not so good for road cars where you brake at different rates all the time.

So yes, if you're going to use it for a race-only application then a balance bar would be great, but as I said, it's like a whole pedal box assembly and a lot of work. The simple option - the proportioning valve - relies on the original balance to be close (which a lot of these kits appear to be actually) but then it's difficult to know to what value you need to adjust it to.

I think the best way to go is EBD or some such brake gizmo. I think they change the balance according to wheel sensors. Sound pretty cool, but I don't think you can just buy a set...

Gary_BremboRT

Ok...here's the deal.

I want to start by explaining the difference between Brake Bias and Brake Balance.

Brake bias, as defined for use in this thread, is the ultimate amount of brake torque as it is distributed between the front and rear axels. This is generally a fixed factor dictated by the master cylinder, disc diameter, and piston area.

Brake balance, as it should be defined, is the way the vehicle responds under various braking conditions. The is an ever changing factor dictated by the suspension and shifts in weight distribution...the tires and the grip between the vehicle and the road...and the brake bias determined by the brake components.

The reason I wanted to explain this is because there seems to be allot of confusion about what bias is and how it relates to balance. Now and days there are allot of choices for aftermarket brake kits. Every company wants to stand out and claim to be the better kit. One company even went as far as claiming to be the leader in balanced braking. Bias is a baseline for properly engineering any aftermarket brake system. Since balance is an ever changing factor, there is no such thing as a magical brake bias that is correct for every driver or every situation.

Some companies have arrived with the configurations described in x838's comparisons because those are the only components they have available. Others may have a personal preference on what they think the bias should be. Now and days with functional ABS...traction control...and other vehicle stability controls most of the brake kits described in this thread are within the allowable limits to be functional.

Bottom line...if you want to dial in an exact bias to match your driving style or conditions then you'll probably want to pick the brake company by the amount of brake pad choices, or possibly install a proportioning valve. If you want the best brake system available, make your choice by paying attention the quality of the kit, the history of the company, the availability of replacement parts, and the reputation of the company within the industry.

redvolution

iTrader: (3)

I helped RB test their new 332x28mm front BBK.

Comparison to stock equipment (factored out pi):
- measured stock piston diameters: 42.3/36.5
total area: 780.385
- measured RB piston diameters: 38/38
total area: 722

Effective diameter of stock rotor: 263mm
Effective diameter of 332mm RB rotor: 283mm (=332-38-11)

(722/780) * (283/263) = 0.996
The RB front kit supplies 99.6% the front brake force as stock.

I used a vernier caliper to measure the diameter of the piston sticking out of the inside of the caliper. I believe just the piston diameter is enough for this calculation but I'm not sure.

If we assume 46/40 for stock and everything else the same, the numbers are:
722/929 ... = 83.6% of stock.

I had no rear-lockup issues on my RS. Given that, I assume one or more of the following:
- the 46/40 numbers are wrong
- the stock bias is massively front oriented
- RB and Mitsu use different systems to measure "effective" piston diameter
- there's another measurement I didn't include which affects effective brake force

nubby

iTrader: (6)

Someone correct me if I'm wrong, but I believe our cars are plumbed with a "X" split in the braking system, so you have front-right & rear-left on one circuit, and front-left & rear-right on the other. So an RS would at least need to be replumbed F/R.

If you have ABS/EBD, that would only further complicate things, and you'd probably have to ditch it in order to run a bias adjuster. There's a brake line for every wheel that comes out of the EBD distribution block, so even if you replumbed to a F/R split, you'd still be stuck with no single point of adjustment for the rear braking circuit. I'm not even sure simple bias adjusters work well with ABS.

The ultimate would be running dual master cylinders with a bias bar adjuster, but you'd either have to custom fab something, or get a new pedal box, and either way, you'd lose your vacuum assist.

I'm looking to run a simple bias adjuster on an RS, so if anyone has done it, please chime in.

trinydex

iTrader: (12)

this post is making the least sense to me... why is rb's bbk making LESS force than stock?

redvolution

iTrader: (3)

Assuming the brake system can generate enough torque to lock the wheels, then reducing the force applied on the front wheels will effectively shift the bias rearward.

Was there another point you didn't understand?

trinydex

iTrader: (12)

ah ok... so you just make it up with pad choice...

fromWRXtoEVO

iTrader: (18)

x838nwy,


The comparison is great, unfortunately is just gives you size parameters when in the real world you actually have to consider additional factors such:

Surface area or rotors
weight of rotors
surface area of brake pads
material of brake pads
material of rotors
disipation heat porcentage of each material based on metal estructure
ventilation of each rotor

Even the rims play a important role disipating the heat, put some steel rims like the GSR Evo in Japan and your temps will remain higher, brake with well ventilated rims and your heat will disappear faster

Sumarizing, you can have a bigger rotor and be less efective than a smaller rotor, there are more variables to consider but good info that you provided .

Carlos

DaWorstPlaya

iTrader: (31)

I agree with Gray BremboRT, while one may be able to adjust the bias on an EVO RS with the help of calipers, rotors and pads, on the EVO's with ABS and EBD it might do very little to help brake bias using the above mentioned method as the EBD will take over when it starts sensing wheel lock and adjust accordingly. I think the EVO would improve braking performance if the brake bias was shifted slightly to the rear as it is very front biased in stock form.