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-   -   Brakes: How to buy brake upgrades? (http://legacygt.com/forums/showthread.php?t=8151)

Xenonk 02-07-2005 04:46 PM

Brakes: How to buy brake upgrades?
 
I decided to put this FAQ together to help people decide how about going upgrading brakes as well as helping people fimilar how to buy brakes to fit for their needs. Not everyone need 16" rotors front and rear and still complain about how they can't stop better than stock.

Q: How does one stop the fastest/shortest?
A: It really starts with the tires. Brakes are one thing, but the main concern is about how the tires grip the road to stop.

Q: Tires? What? I thought we were talking about brakes?
A: Tires are the only thing that keeps the car in contact with the road, you are relying on 4 little patches of rubber to keep a 3000+ lbs car on the road. So yes, tires do make a difference. For example, if both cars had super awesome brakes, but one car had rubber soft slick tires while the other car had just bare rims, which one would stop faster? It's obvious that the tire will get into better grip (friction) with the road than the bare rim. It's hard for bare metal to dig into the concrete. If you dont believe me on the matter that tires dont make a difference, ask race car drivers why they have to use racing slicks.

Q: Ok, so tires are upgraded, now what?
A: Hopefully, the tires you chose helps you narrow down what kind of brakes you should look into. I have broken down the three common tires you will find and 3 kinds of brake upgrades you can get along with the car.

Tire A, Daily driving: This is the kind of tire that would be on your car most of the year and winter driving is possible since it could very well be an all-season tire.

Tire B, Spirited driving, Autocrossing for Street Touring: This is the kind of tire that is more dedicated for street use in the summer or possibly an autocross street touring race setup. The tire is fairly soft and the potential for harder braking is possible (also less chance for the ABS to come on).

Tire C, Race and Race-practice driving: This is where your tire is barely DOT-approved and street legal, the tires barely last more than 5,000 to 10,000 miles conservatively for street driving or only 100 miles for race use. These types of tires are sticky.

Brake Upgrade A, conservative driving: This is the setup you are looking for that you expect to keep on your car for a while unless the brake pads run low. The key things to upgrade are better brake fluid, better brake pads. The driving habit is mild and delicate braking, long drags, and low speed stops (think slow daily driving). Look for a brake pad that has a high coeffiecent of friction (for that quick bite) and low operating temperature (so that winter or cold brakes will still work).

Brake Upgrade B, spirited driving: This setup is something that might need some higher performance pads, better rotors to help prevent brake failure or poor performance. Things to look for are stainless steel brake lines, better brake fluid, slotted/cross-drilled rotors, larger or higher operating temperature brake pads.

Brake Upgrade C, hard driving: This setup is to help you get the most out of your brakes without worrying about overheating/overworking your brakes. This setup is usually for racing use only since the brakes (and tires) need to warm up first before they work properly. Things to look for are racing brake fluid, bigger rotors with slots or crossing/drilling, racing brake pads, stainless steel lines, bigger calipers that can handle larger brake pads. All these parts help you keep the brakes work in the higher braking temperature ranges. Overheated brakes are just as bad as having no brakes at all.

Q: Are slotted and cross-drilled rotors needed?
A: Slots are useful to a point when you are looking for a way to prevent glazing of the brake pads. Glazing of the pads happen when you overheat the brake pads (either too hard on the brakes and not big enough of a rotor to dissapate the heat fast enough thus makes the pad material harden and it starts to lose its frictional properties. Cross Drilled really has no real use now as brake technology has advanced.. it does have an appealing look to them, but as for today, you dont need them as they serve next to nil on purpose. Specifically on the Legacy (GT or 2.5i) the brakes are fairly well using just the stock rotors. The weight of the rotors (mass) is pretty heavy.. more mass also helps in heat capacity, so the more mass you have for the rotors, the more repeative braking that you can do. Big Brake Kits do benefit from this very reason, but a few other brake tests has shown that the thickness of the plates and the overall thickness of the rotor proved to be more of a useful design than just the overall diameter of the rotor [Motor Trend did the study about 2 to 3 years ago I believe]. Blank rotors are fine and does the job, especially for a daily driver that doesnt need that heat capacity.

Q: So what kind of brake pads out there?
A: There are a lot of brake pads out there, things to take consider are the three main attributes that usually 2 attributes are offered in a braking pad:

-Dusting/Noise (how much they make your bling rims dirty)

-Temperature (the range of temperature of which the pad works)

-Friction (how well the pad has the initial bite and feel to the rotor)

It's very hard to find a brake pad that can be awesome in all 3 attributes. Street pads will have great low noise/dusting, good friction bite, and typical low temperature range. Performance pads will have good friction, good temperature range, and typical medium dusting. Race Pads have great temperature range, good friction, and lousy dusting (very dirty).

Q: What temperature is right for me?
A: If you are looking for daily driving and expect to drive through a winter season, look for a brake pad that can operate in low or freezing temperatures. If you are looking for autocross and very light track days, look for above freezing to 800 F temperature ranges. Very rare that a daily driven or street driven car hit temperatures of 1000 F unless you are that crazy to hold the brakes down at near full force while driving at 40 mph for 15 mins. Racing brake pads start near the 150F to 1500F+ range (so somehow the driver needs to warm up the brakes before actually using them).

Q: How do I pick a good brake fluid?
A: The thing is to look for the HIGHEST WET BOILING POINT (as brake fluids do soak up moisture in the air and causing the fluid to fail and feel mushy). Change your brake fluid at least once a year or every 15,000 miles for the best pedal feel. ATE Super Blue fluid is probably the best "bang for the buck" at $15/bottle for a full flush. Always use a fresh bottle, dont use a bottle that has been open for more than a month as it has probably soaked up dirt and other moisture in the air that would make the fluid ineffective.

Q: What about stainless steel lines?
A: Usually designed for better pedal feel for less pedal brake travel and less flex in the lines. It's an upgrade that is really up to the owner as stock lines offer enough PSI of fluid for the caliper to clamp with enough force. Unless you are upgrading your master cylinder and larger calipers, upgraded stainless steel brake lines with higher PSI rating is not neccessary

Q: What about big brake kits?
A: Big brake kits are used to make use of the tires' grip potential and dissapate heat faster. It's not neccessary for a street car to run with larger brakes unless you run the Autobahn or something and have the tires run them. Also, check the brake pads that the brake kits come with. There's no sense in getting bigger brakes (more weight) if the brake pads are lousy "performance" pads that can overheat and glaze.

If there are any other questions, I'll will answer them on a case-by-case basis from here on out.

SWortham 02-07-2005 05:08 PM

Nice writeup. Just noticed this statement...

Quote:

Originally Posted by Xenonk
Q: What about big brake kits?
A: Big brake kits are used to make use of the tires' grip potential and dissapate heat faster. It's not neccessary for a street car to run with larger brakes unless you run the Autobahn or something and have the tires run them. Also, check the brake pads that the brake kits come with. There's no sense in getting bigger brakes (more weight) if the brake pads are lousy "performance" pads that can overheat and glaze.

That's probably true of the LGT, and maybe that's the point. But my Hyundai Elantra, for example, came with 10.1" rotors which I upgraded to the 11" Tiburon OEM brakes after I upgraded the wheels. The larger rotors, calipers, and pads do provide a larger heat capacity but more importantly the leverage is improved. The result is a dramatic improvement in stopping power at the expense of some added unsprung & rotational mass and a lighter wallet. So it definitely depends on the car whether it justifies an upgrade to a big brake kit.

kanoswrx 02-07-2005 05:13 PM

Good write-up, agree 100% with that.

mwiener2 02-07-2005 05:15 PM

O boy, my first thingy I've done as a mod... I stickied this.

Xenonk 02-07-2005 05:20 PM

thanks Mr. Moderator!

Keefe

Th3Franz 02-07-2005 09:07 PM

Keefe, what about ceramics? I was watching SPEED and they were talking about ceramic brakes and were showing Porsches driving around a track. Just wondering if you had any information about them in particular..

Xenonk 02-08-2005 06:03 PM

Carbon Ceramics = expensive, and they have a very short lifespan.. they are also lighter in weight and can deal with a high operating heat range, but once they cool down from that high, that's the end of their life cycle. Eventhough Porsche offers them on their Production cars, it's a very costly option to have (think in the range of $20k to $35k for a set, front and rear and matching brake pads and calipers). On the street, they will work like any brakes, nothing special.. the real potential is when they are driven hard and that there's no fading that occurs during the operation of high heat.

Keefe

Sands 02-13-2005 02:41 PM

I disagree on several points.

Cross drilled rotors WILL crack if driven on the track. Bad idea. I've never seen a set of cross drilled rotors not crack, but then most track cars don't used cross drilled rotor because they crack.

Stainless lines are probably one of the best bang for buck upgrades for a track day. Above 8/10th brakeing effort, your pedal will be linear. With rubber lines, your pedal will require esponentially more force to stop at the same rate as with stainless lines. They do not require uprating your master cylinder or calipers to have an effect.

For fluid, I alternate between ATE Super blue and ATE gold. The color change makes it easy to tell when you've changed out fluid.

Sands 02-14-2005 08:14 AM

SS lines will also have much better modulation and pedal feal then rubber lines, but only at or near threshold.

The caution with SS lines is that dirt can work their way between the braid and the hose under it, causing abrasion and potential failure. This will be a slow process and requires periodic inspection of the lines for weeping. Not a big deal if you pay attention to them.

If you are tracking your car, you should be doing a brake job before and after to change pads. This is a good time to do this.

The other caveate is that SS lines are often not DOT approved, which can cause issues if you get into an accident due to brake failure. As long as the lines have not failed, there shouldn't be an issue, but forwarned is forwarned. Personally, I am willing to take the microscopic risk for the benefits SS lines bring.

Oh, my suggestion on the fluid is not in dispute with the orginal post. I'm making the suggestion to make it easier to bleed brakes.

Xenonk 02-14-2005 08:30 AM

I would like to say there is basically two types of performance driving. One is driving for qualifying/sprint-race speeds (pushing 10/10ths or even more so to get the fastest time and disregarding the parts on the car for damages because at the end of qualifying or a short sprint race, you'll replace them anyways for the next race). Expect to see a lot of cracked rotors and the such at these kind of speeds. The second type of performance driving is known as the race speeds (pushing the car to the limit that will outlast the other drivers and their cars, this is very common when it comes down to enduro races). Slotted and Cross-drilled rotors are made for a reason still. 24-hour and 12-hour races have a meaning of how to stay in the race with precision and conservative driving at the highest level. Sure, cross-drilled rotors do crack, but for track practice and learning the lines and conserving your brakes to last for the day isn't. www.racingbrake.com has made some of the better racing rotors I have dealt with (over Baer, Project Mu, and even Brembo rotors). Not all rotors are designed the same way, as some of the brake rotor's veins for cooling go a long way and number of holes also add up to the structural integrity (or lack of) about the rotor.

I have been on the losing side of a 3-hour enduro as my team lost the race in their class (leading 2nd place when the front full blank rotors and race pads finally glazed up at 2 hours and 58 mins, of which we did an attack starting from 4th place at the last 10 laps which made them overheat). The driver lost all braking power on the 2nd to final lap and buried the car into turn 1's tirewall at www.virclub.com

Keefe

apexjapan 02-20-2005 11:08 PM

Well, I'm late in this, but some points on blank vs. slitted vs. cross-drilled rotors.

For the street, blanks are more than adequete. They simply don't look too cool, which is why there is a large amount of slitted/cross-drilled rotors on street cars.

For the track, slitted rotors make the most sense in terms of circuit performance, especially over longer periods.

Which leads us to cross-drilled. There are two types of cross-drilled - ones that are actually, physically drilled, and ones that are cast with the drill holes in place (Porsche rotors). The cast-hole rotors are fairly sturdy. And expensive. At the track, rotors are like bags of chips while watching the superbowl - expect to replace them regularly. So if you are serious about your track braking, balance your needs vs. replacement costs.

Cross-drilled rotors cracking: All rotors have the possibility of cracking, cross-drilled (non-cast) are simply the most prone to it. Yet you can easily make a cross-drilled rotor last longer without cracking than even a blank rotor. The main failure point for rotors is not on the track itself, but after you leave the track. Most people go 100% (or more, at least for them) on the track up to the last second, pull off, stop the car, set the e-brake and let those expensive rotors cool off rapidly. <crack!> What really does it is the brake pads - the rotors are exposed to air everywhere but the pads, and when you let it cool off from Extra Crispy to Slightly cool with most of the rotor cooling off *much* faster than the section of the rotor under the pads, the difference in temperature will make *any* rotor brittle quickly.

If you want your rotors to last after track racing, either take one or two really slow, easy cool-off laps before you pull off (if you have that choice), or try to slowly roll around somewhere to let the brakes cool off more gradually and evenly.

Porsche owners with those expensive ceramic rotors have had some fairly expensive replacement bills (think half the cost of WRX or more...) after relatively low mileage on those rotors because they do just that - pull in and stop. Even Porsche thought they would know better...

Cheers,

Paul Hansen
www.avoturboworld.com
www.e-bacs.com

Sands 02-21-2005 11:53 AM

Paul - yup right on. Forgot to talk about the whole cast vs. drilled. thanks

IMHO, cross-holed (I'll be generic) just isn't worth the hassle or expense. It's a total PITA to do cirlces in the parking lot waiting to cool the brakes down.

jerami1981 03-15-2005 01:45 PM

I had cross drilled rotors f/r on my 98 camaro Z-28, ran about 25,000-30,000 miles on them, and they weren't easy miles. I liked to run that car at high speeds out in the open, as well as on the back roads, lots of hard braking from speeds ranging up to 160 mph, to lower speeds of 30-40, and i did lots of hard braking, hard excel, hard braking..ect...never had a problem with brake fade, and i never cracked any of the rotors. It all depends on what you are going to be doing. If you are going to be braking hard a lot from higher speeds, or lower speeds, the added saftey of slotted or cross drilled rotors is probably worth the extra expense, since life is priceless and it can save one. If you are a normal driver who obeys all posted speed laws, a normal rotor will be just fine for you. IMHO

TPM 07-29-2005 01:06 PM

Hi,

I recently visited LegacyGT forum and noticed you have been actively giving advice to members with your in depth experience and knowledge, which has received my attention and respect as it hard to find nowadays in various medias or web forums.

Since your posting generates some good discussions about drilling / slotting again just like anywhere else, I would invite all the members to view our comparison on different disc surface finishes.

http://www.racingbrake.com/main/two_piece_compare.asp.

The rotor cracking is caused primarily due to poor casting quality or more precisely - Microstructure, this makes the rotor more prone to deformation (warping or cracking) under heat. Thermal fatigue makes the rotor loses it's strength, not because of the drilling. Jerami1981's experience should well support my statement.

Anyone, especially racers, should be aware that a well performed rotor shall be made available from ground up i.e. good material (casting and heat treatment) which is more resistant to heat and better designs that will drain heat faster and keep the disc cool, rather than centering around "drilling" or "slotting" which although can change the performance to some extent, would not principally change the physical property that dictates how a rotor performs. See http://www.racingbrake.com/main/rotor_is_important.asp which was in response to Mazda 3 forum discussion about aftermarket rotor. http://www.mazda3forums.com/index.php?topic=24716.0

Our rotors are built from our experience and know-how. See our patent pending designs http://www.racingbrake.com/main/technology.asp. All designs are simple to understand and work. For example WRX enthusiasts love our rotors, while other manufacturers /suppliers including OE keep warping, why? it's is because our patent pending design of reinforced rib that makes the difference:

http://www.racingbrake.com/images/legacygt.jpg
http://www.racingbrake.com/images/legacygt1.jpg

Best Regards

BatChips107 09-28-2005 08:18 PM

WIll aftermarket big brake kits for the WRX or even the 2006 WRX brakes fit the LGT? I must remedy this braking problem ...


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