legacycentral bbs

Im not sure I understand this.

I get that bigger brakes = more braking power, but it's all limited by the tires, right? You can't brake harder than your tires can take. So if braking as hard as you can causes the ABS to kick in, wouldnt that mean your brakes are already as big as they need to be?

that is a very true statement, however, since your brake rotors are bigger they have some things going for them, 1, you dont have to brake as hard to stop at the same rate as without bigger brakes, and 2, the bigger rotors have more mass that takes longer to "heat soak" , when brake pads fade they release gases from the burnt up organic material in most brake pads, and create a thin layer of gas that separtes the rotor and the brake pad while braking. remember you need to use 16'' rims or larger when switching to WRX brake rotors, you will also need the caliper and the backing plate thingy. hope this answers some questions.



~Josh~

Better resistance to brake fade and you would have to get better tires to fit them anyway (16" wheels at least to clear them and likely better, wider tires in turn). They are not necessary and to most people I would recommend keeping the stock brakes in primo condition as they are excellent brakes when in good shape that easily hold their own with modern cars combined with halfway decent rubber. You also don't have to worry about lock up without ABS as much as with the WRX brakes. Still, when they bite and you lay into them and throw your passenger into the belt as they swear out loud or grit their teeth in fear, it's worth it!

Missed the above post - all you need are the calipers, brackets, and rotors.

Steve

You can use 15" wheels.

What 15" wheels? Mine barely clear the Foresters.

Steve

Splinter wrote: bigger brakes = more braking power

This isn't correct. Bigger brakes are for 2 reasons, better resistance to heat soak (due to more mass) and more surface area to cool. Moving the pistons outward slightly increases the effectiveness of the brake, but since it only matters relative to the rear brake, this isn't necessarily an improvement.

More pistons make for better brake feel and marginally more even pad wear.

If your brakes can't lock up your tires, you are in a damn scary car.

Simply put, if you never have any problems with brake fade, then don't upgrade them. If the problems aren't too severe, just change to a higher heat range pad, that will do a lot.

scottzg wrote:If your brakes can't lock up your tires, you are in a damn scary car.

My stock brakes on my L lock up just nicely

My brakes have trouble locking up my tires. I also have good tires.


I know this is just my opinion, and I'm going to get flamed, but until you've ridden in a car with amazing big brakes, (m3 or whatnot) and experienced the full braking power on good tires, you won't understand. I'll just say that i'm certain my car could not stop nearly that fast.

that's tires and suspension.

yep. You could have tiny 4-wheel drums, and if they had the power to lock the tires, you'd still stop pretty much just as quickly. Until you're at the point where the brakes are fading/overheating, size doesn't matter (woah did I just say that?).

I noticed a huge improvement in brake feel going from worn stock suspension and 185/70-14s to STi suspension and WRX wheels and tires, and they'll still lock up just fine, although I can get them to fade pretty easily.

One other thing, if you just put on WRX fronts and leave the rears, the bias will be too far forward, and it will take longer to stop because the rear tires aren't doing their share of the work.

One of these days I'll buy some rotors and rear caliper brackets and put on the WRX fronts and H6 rears with Axxis Ultimates and SS lines sitting in my room.

Correct me if I'm wrong, but aren't the WRX front rotors the same diameter as a Legacy turbo. It's just that they have two piston calipers that cause the clearance problems for 15" wheels.

And the WRX rears aren't vented anyway. I just went with good fluid and Carbotech Bobcats. My car is in the shop right now, so I can't vouch for the setup, but it was the suggestion of my mechanic who is also a road race instructor.

Legacy turbo front brakes have 2 piston calipers oem. The wrx rotors are larger.

The '06 wrx rears are now vented too.

And the 06 WRX has 4-piston front, 2-piston rears. I'm pretty sure they're the same brakes and the older STi had (elsewhere in the world), just with red painted calipers.

I was going to just get new fluid and pads, but I have a caliper that tends to stick and got all this stuff very cheaply (~$250 for all the calipers, front brackets, pads, and ss lines), so I thought, hey, why not? They'll fill out the wheels a bit better, too.

Guys.....being able to lock up brakes is in no way an indication of how well your braking system is.

There's so many factors that play into a well setup brake system: rotor size/venting (directional/non-directional vanes, etc), caliper design (floating/fixed), caliper size, suspension, weight shifting/transfer, bias controller (proportioning valve/EBD system, etc), master cylinder size, amount of booster assist, pedal ratio.

Drum brakes typically produce higher braking forces, but tend to overheat much easier. Jamal, your comment regarding the drum brakes stopping as well is not true.

There's so much more that can be gone into....but regarding the question posed. The WRX brakes give you two main things over the stock brakes. Larger rotor, which increases the thermal capacity of the system, ie it'll take more heat to overheat the brakes. Secondly, you get more brake torque, which in turn gives you more stopping force. The catch is that unless you have sticky enough tires, you may not be utilizing it all. As a side benefit, you'll probably be able to find a wider range of aftermarket brake pads & rotors for the WRX brakes then you will for the older legacies.

Also, as mentioned, the WRX brakes will shift bias forward, which some don't mind, and others, like myself don't. So there are some other issues that might need to be addressed.

The only thing I can add that Josh said before me, is that larger brakes allow you, as a driver, more room for error in modulation.

It's easier to balance on the jagged threshold edge of braking when you have more mechanical advantage over the wheels. Larger brakes, strictly rotor diameter and no other changes beyond this, will allow you more mechanical advantage, and thus require less effort to completely halt the rotor. So you can very easily juggle your middle pedal to keep your tires on the verge of locking.

With WRX brakes, good pads all around, and sticky tires and a slight rearward bias advantage, on a slightly better than stock suspension, with a great alignment, and stainless lines, I can lock all 4 225/45/17 RE070's without MUCH effort, and I can balance on the threshold from unsafe speeds, without so much as blinking an eye.

With more confident brakes, you can simply go faster.

Oh, and I've driven an M3.

Legacy777 wrote: Secondly, you get more brake torque, which in turn gives you more stopping force. The catch is that unless you have sticky enough tires, you may not be utilizing it all.

When you can increase brake torque by changing the MC diameter, why does this matter other than relative to the rear brakes?

I'll definitely second Phil's comments.

I can get mine to lock, but the modulation and ability to control lockup is much better. This is also aided by the use of a single diaphragm booster and brake booster brace.

scottzg wrote:When you can increase brake torque by changing the MC diameter, why does this matter other than relative to the rear brakes?

Changing the MC diameter does not change brake torque. An increase/decrease in MC size affects pedal travel and pedel effort (but not as much as pedal travel).

So I'm not sure if that clears things up, or if I'm not understanding the question.

excuse me, i meant brake booster.

I posted that when i was verry tired.

Wandering in the desert like a Jew will do that to ya

scottzg wrote:excuse me, i meant brake booster.

I posted that when i was verry tired.

Changing the brake booster won't change brake torque either....

i read the hole post all i have to say is how do i get my rotors to stop vibrating, i have p7 tires, braded lines, new brake fluid, new rotors, new pads, my car dont stop fast and the rotors warp all the time i need to stop fast with out makeing the wheel shake and brake pedal to vibrate.

resurface your rotors.

I'm assuming you bed your pads correctly Nico? If they keep warping on you, have you checked your calipers to make sure they slide properly, sticky guide pin?

no i did all that belive me my stuff on my car is F1 ready, i pound on my brakes but the vibration kills me. it happens when i use the brakes hard.