Need help deciding

[skid542]

Now I don't even have the turbo fronts but I have a sweet turbo setup in the back. My car is also lighter than your turbos by a few hundred pounds but while I look forward to the day I get my turbo fronts, I am extremely content with my current setup.
One thing I think that everybody is overlooking is the advantage of having a balanced brake setup. If you are too far foward then you aren't using your backs to the fullest potential and there is an certainly an optimum setting, having all 4 lock at the same time. My backs currently lock just slightly before the fronts and the difference that the improved brake bias has been tremendous. Entry speeds can be higher because no only can I stop quicker, duh, but when I get on the brakes there is less of a forward weight transfer and the correlates to a smoother entry and exit. If you have to decelerate hard from high speeds it is much more stable as you aren't being thown and pitched forwad as much. Unless you are going to upgrade the back brakes to match the improved fronts, I would just get a good set of pads and a good set of cyro'd rotors that will withstand a harsh pad. If you're going to get 4-pots then go ahead and upgrade your back to the new B4 or equivalent. Just my two cents.

[jake15]

I'm going to upgrade the back too, i just havent decided if i want to get a matching perrin rear brake setup, or keep my stock stuff (since their already pretty good) and upgrade pads and rotors. does anyone know of a good place to get some nice cryo-treated, and maybe cross-drilled or slotted, rear rotors for a turbo legacy? i have stainless steel lines that go on when i decide on a brake setup.

[scottzg]

One thing I think that everybody is overlooking is the advantage of having a balanced brake setup. If you are too far foward then you aren't using your backs to the fullest potential and there is an certainly an optimum setting, having all 4 lock at the same time. My backs currently lock just slightly before the fronts and the difference that the improved brake bias has been tremendous.

Rear locking first leads to oversteer under braking. This is a VERY BAD THING. If you slam the brakes and swerve, or brake too late, the locked rearend will outrun the front and spin ya. It's unlikely in this 4 wheel spin that you'll remember to take your foot on the brake and nose the gas to pull yourself out. Stock brakes are set up for about 10% front bias, and imo this is perfect for mommy and RacerX. All 4 locked at the same time stops you wicked fast, but it could give you the same results with a little weight transfer. I'm not disagreeing with you skid, proper bias is very important, and more rear bias will stop you faster, in theory, but it cuts into your "safety net." FWIW, i have spun my car in the dry on the freeway by braking with my completely stock brakes.

Crossdrilled rotors (expecially the variety where they drill the rotor after) are not necessarily an upgrade. Look into it first.

Change both front and rear pads to the same variety. Just changing one half means your bias will change as your brakes heat up.

Oh, and i'll just throw this out there- an uprated rear swaybar is picking that inside wheel off the road, decreasing patch. So an uprated rear bar is like changing your brake bias only in turns.

[THAWA]

maybe not you personally scott, but it was mentioned by a few people.

[Legacy777]

I was sure to miss some detail in my rebuttal. I assumed equal piston sizes.

Josh, as our resident brake guru, everything else i said is right though, right?

Yeah, everything else looks fine.


One thing I will comment on about the brake pad area is.....it's not really that big a deal. Slightly larger pad area isn't going to gain you much more in terms of braking.


When you look into upgrading your brakes, yes you need to look at the car as a whole system....and not just the fronts or rears. It's really something that is rather complex when you dig into it further. I could write a pretty long/in depth paper on it. But I'm not......at least not here.

Just an FYI....the subaru 4-pots....and probably other BBK's have smaller pistons then the stock brakes. This actually reduces brake torque....when rotor size is kept constant. This shifts bias rearward, and typically improves the overall chassis braking.

I know I've pushed this file out before, but it's definitely a very useful document in figuring out what components do to your overall braking system, when compared to the stock setup.
http://www.main.experiencetherave.com:8 ... kemath.xls

[skid542]

I agree 110% percent with you Scott that having the back lock first is not ideal and can be scary. That's why I've made a several posts about getting a more agressive front pad. I am fully aware of the dangers of having the back lock first, I've spun it once in the rain going into a turn that way. My point was that if you are going to be moving your brake bias, it should be towards the back and not further towards the front. As you said, a more nuetral biasing requires more alertness and caution under hard braking. I won't let my mother drive my car under the current brake setup because I know she wouldn't know how to handle such a reduced safety margin. Biasing is definately very personal preference matter that encompasses a lot of variables. Personally I want my fronts to lock just before my backs.

And yeah don't get cross drilled rotors Jake. Have you read the article Josh wrote that's on the main legacycentral site? I personally like slotting, granted I can't say just how advantageous they are to me but I do like the look and the fact that they are removing gasses under hard braking. When I do my front setup I will be getting slotted to match the back, I think though the slotting makes the brakes a little louder. As far as suppliers Jake, sorry not too much help there.

[evolutionmovement]

I've never had a need for perforated rotors personally. I haven't faded the front brakes currently (WRX fronts with Hawk HPS) and the old OEM system with cryo rotors and EBC pads wouldn't fade at all either and still stopped the balls (highly recommended for stock power as a very effective, long lasting, cheapest performance set up).

I'd like to measure my braking distance threshhold braking with the current set up. I'm sure it would be competitive with better modern cars.

Steve

[scottzg]

I'd like to measure my braking distance threshhold braking with the current set up. I'm sure it would be competitive with better modern cars.

I'm pretty sure that your straight line braking distance is longer than stock, as it is generally accepted that the wrx brakes move the bias forward. On the other hand, its probably competitive with modern cars as a stock legacy has very very good brake distance.

Skid, a more "agressive" front pad may just have a higher ideal heat range, making the brakes even more rear biased when cold and less so as you heat them up. It's tough to tune brakes with different pad compounds.

[skid542]

I've measured my 60-0mph to be 115ft, including reaction time. During that test I even had one tire lock momentarily. This is plenty acceptable to me. I will be curious to see how the bias and distance is after I get new pads, looks like it's going to be another month till I have funds .
But I will agree with you again Scott in that changing pads isn't really the proper way to tune the brakes. If my cold bias doesn't change much that's fine, I can live with that. However, if I can get the fronts to lock while I'm pushing the curvy mt. roads hard then I'll be even happier. I know it's kinda a crap shot but it may be worth it. There are plans for turbo fronts down the line but I can't justify the money on it right now. My rears I got because I couldn't pass up the deal.

[evolutionmovement]

I'm sure my car brakes faster now, but distance I'd wish I could compare to my last set up when it was new. I have a wagon and there's more rear bias than the sedans, but there is more front bias than before. I have to let the weight shift a little before I can lay into them, but once they bite I can push myself tight against the belt and the car just kills off speed at a rate that would certainly beat the original system. However, due to the need to be more careful with the initial weight transfer, I think overall distance would be about the same (to my optimized stock system).

Steve

[93forestpearl]

Doesn't the term "better brakes" really mean more heat capacity of the braking system? I've cooked my brakes plenty of times and it really sucks. Super Blue Racing fluid helped alot, mainly with feel and increased fade resistance, but I still end up with several pad outlines on my rotors when I take them off.

All of these things combined, meaning bigger, cryoed rotors, larger calipers, etc, just increases the heat capacity of the braking system, thus increasing the fade threshold. This means you can brake harder and longer without the brakes fading on you. Am I being too simplistic on this?

I've been eyeing those Subaru 4-pots for quite some time. Seem like a good deal for what you get. Yes it increases your unsprung weight, but I'll take the weight for drastically improved fade resistance any day.

Did anyone see the article in Sport Compact Car when they cooked the brakes on their EVO and STi? It was impressive. The rotors were bright orange, in excess of 1000 degrees by their temp gauge, and they still worked great. Thats what I'm talking about
The picture with the STi's pads on fire was cool too.

[skid542]

You are right in that more mass, cyro treating, etc. does increase the thermal capacity. Rather than thinking about strictly heat, think of it in terms of energy.

If you're getting pad outlines it's because you are allowing yourself to come to a complete stop after running the brakes hard. Try to coast that last 10-15 feet and do the final stop with the ebrake and just hold the ebrake while keeping your foot off the brake pedal. Let the pads and rotors cool a little before sticking the pad against the rotor.

[93forestpearl]

skid542- You are right that heat ~ energy, thermal energy rather. I was just thinking that all these upgrades, aside from SS lines, are to increase the thermal capacity of the system. Granted, you can get more aggressive pads with more friction, but the enemy of brakes is heat, at a certain point.

I realize that the outlines are from stopping on hot brakes. I always try to not come to a complete stop when I know they are hot. Duluth sucks for that because 80% of the town is built on a 30 degree slope. We are famous for the hills here, but it is hell on brakes, and cars in general.

[skid542]

Heat is definately an enemy at a certain point but vented and cyro'd rotors will take a lot of heat. I certainly realize that my brakes are inferior to my friend's STi but my car is also lighter and less powerful. I look forward to when I upgrade the fronts to turbos but I'm still happy as is now. Maybe I'm just too easy to please .
My town isn't quite as bad as yours but it's not good either so I can understand your frustration. I also try not to push the brakes too hard when I'm in town, but I know how things can be some times . Are your rotor's cyro treated?

[93forestpearl]

My rotors aren't cryo treated. They are el-cheapo rotors from napa. I've gone through a couple sets in my five years of college up here so I usually do brakes on the cheap. By the end of the summer I'll get the suabru four pistion setup and I think I'll get cryoed rotors for them, if it doesn't come with them.

Being in a town that is pretty much one big hill does kinda suck, but the scenery is spectacular(over lake superior). I could engine brake more to save my brakes, but I don't like engine braking all the time. So I'm stuck between a rock and a hard place. I usually just try to not come to a complete stop.

Personally, I'm kind of a perfectionist and it sucks some times Its good when you want to be an engineer, but sucks when it comes to my pocket book and what I want my car to be. Good thing I like sales alot and that will make me much more money in the end