Brake Upgrade Guide....

BAC5.2 · Post by **BAC5.2** » Thu Nov 11, 2004 8:04 pm

I'll post here my upgrades with dollar figures and sources. If all goes according to plan, I'll have a very balanced and consistant braking setup.

- WRX Front Calipers/brackets/rotors: $120 (9,000 miles, picked up, from NASIOC)

- Stoptech Stainless Steel brake lines: $90 shipped from Ebay. Store was www.vividracing.com, they are GREAT to deal with.

- ATE Superblue brake fluid: $9.95 from www.OGRacing.com (I picked up, as they are local to Virginia).

- Carbotech Bobcat brake pads (soon): $99 for the WRX fronts, $109 for the Legacy Turbo rears. I haven't ordered these yet, but I will shortly. I am going to run junk pads until I can afford to buy new rotors all around, then I will do the rotors (Racingbrake fronts and Brembo OEM rears, all cryotreated).

- BF ABS Brake Prop Valve: $10 from junkyard. Still haven't gotten this yet, but I will before I do any of my brake work.

That's about it. All of this should equate to some amazing brake feel, modulation, and power. Stock, our brakes can't stop a hefty and sticky tire with any authority. Hopefully, my upgrades will help that. AND, it doesn't really break the bank, so that's a plus also.

When I get it all done, I'll write an update on whether or not it was worth it. I am positive that it will be though.

QuickDrive · Post by **QuickDrive** » Thu Nov 11, 2004 8:39 pm

Sounds like a good setup.

I too will be upgrading to WRX Fronts in the near future. (Spring/Summer)
But I don't think I'll go much more other than stainless lines and new OEM Rotors F/R.

What's the Brake Prop Valve do?

tris91ricer · Post by **tris91ricer** » Thu Nov 11, 2004 8:51 pm

The prop valve does nothing more than give you a better feel, from what i understand. ask NuwanD, he has that in his setup, i think, and he could tell you more firsthand details..Hopefully he'll chime in on this one.

tris91ricer · Post by **tris91ricer** » Thu Nov 11, 2004 8:54 pm

really not bad for an estimated ~$230.. good shopping, Phil.

BAC5.2 · Post by **BAC5.2** » Thu Nov 11, 2004 9:23 pm

The BF prop valve raises the rear brake cut off point.

Vikash has the graphs, but it basically allows more rearward bias. This is good because it will help offset the heavy front bias that is inherent in our cars. Of course, I'll be getting bigger brakes up front, so this will just make the new setup feel more like stock bias.

Sticky pads are going to be great. Carbotech says they expect to get almost 50k out of the pads they have on their work trucks. Bobcats are the way to go.

professor · Post by **professor** » Fri Nov 12, 2004 4:16 pm

I'm interested in hearing how this goes. My brake pads / rotors are new, by the previous owner, but the pads are serious bars of soap. They really suck. What stock size pads are good, for say $50 ? I've liked PBR and Pagid in the past on the BMW.

BAC5.2 · Post by **BAC5.2** » Fri Nov 12, 2004 9:28 pm

For 50 bucks, there aren't many good pads. I paid like 65 for NAPA "premium" pads for the front of my Legacy Turbo.

I am going to turn the rotors on Tuesday, and hopefully have the front pads at least in time for that.

QuickDrive · Post by **QuickDrive** » Fri Nov 12, 2004 9:35 pm

I Just realized something....

Upgrade to WRX Brakes will mean an upgrade to 16" Wheels year round.

I just spent close to 500$ on some goodyear ultra grip Ice radials, so I guess I'll be replacing OEM fronts until those are toasted.

90LegAWD · Post by **90LegAWD** » Fri Nov 12, 2004 9:36 pm

axxis metal master and ultimates are under $50 for a front set

Brat4by4 · Post by **Brat4by4** » Sun Nov 14, 2004 10:51 pm

With just the stock WRX front pads (they came with the calipers) my brakes work really well. I can kick in ABS at any speed on any surface. And they held up really well at the track. But good pads should make the setup even better. And I need to get my prop valve installed, I already have mine

Post by **Legacy777** » Mon Nov 15, 2004 7:46 pm

To be quite honest.....the BF prop valve on a BC won't really do much.

Yes it bumps the split point pressure up about 90 psi, which does help, but you don't see that increase in pressure until what I consider medium pressured braking.

I really didn't notice much when I swapped it on my car, but oh well. I've got a spreadsheet with a lot of brake info, percentage increase/decrease for various brake setups.

greg donovan · Post by **greg donovan** » Mon Nov 15, 2004 7:59 pm

Legacy777 wrote:To be quite honest.....the BF prop valve on a BC won't really do much.

Yes it bumps the split point pressure up about 90 psi, which does help, but you don't see that increase in pressure until what I consider medium pressured braking.

I really didn't notice much when I swapped it on my car, but oh well. I've got a spreadsheet with a lot of brake info, percentage increase/decrease for various brake setups.

what about under hard braking?

as far as pads go i have the PBR premium pads from primitive on my sedan. 100 total for all four corners. that in addition to the willwood high temp fluid transformed the braking of my car. i did the fluid first and that made the biggest difference tough. the pads really minimized fade over the old OEM pads.

BAC5.2 · Post by **BAC5.2** » Mon Nov 15, 2004 10:34 pm

Yea, the only time I want more rearward balance is under HARD braking. During normal braking, I really don't have much concern or interest in bias.

Post by **Legacy777** » Tue Nov 16, 2004 12:54 am

At the split point pressure of the wagon valve, 640 psi, you will see a 13.25% increase in rear brake torque over the sedan valve at the same pressure. As I mentioned I consider this "medium braking"

In the "heavy" braking zone, percentages decrease to around 10%

If you would like to see the work up, go to the split point data tab in the following excel workbook

http://www.main.experiencetherave.com:8 ... kemath.xls

WRXdan · Post by **WRXdan** » Tue Nov 16, 2004 4:54 pm

Bobcats are great pads, way better than the parts store junk.

BAC.....BED YOUR PADS IN!!!!!!

Brat4by4 · Post by **Brat4by4** » Tue Nov 16, 2004 6:15 pm

10% is still significant. I feel this will help my car tremendously because it just plain locks up the fronts too quick. But I will see when I actually install it. I wish I had more time to get all the stuff done to my car I want to do.

Post by **Legacy777** » Tue Nov 16, 2004 6:32 pm

Actually 10% change in brake torque really doesn't amount to much change in brake bias.

You'll still probably get front lockup more easily, but for the price and ease of swapping valves, why not.

Brat4by4 · Post by **Brat4by4** » Tue Nov 16, 2004 7:21 pm

Ok. Yeah, any rear biasing is going to help. Plus, part of the problem is my tires. So with some real tires, real brake pads, and real tires... wow, I honestly can't imagine my car stopping faster than it does now.

And I don't think I need the larger Legacy brake system they have now, yet. But who knows, as my driving skills improve (and my car velocities increase) I might start using my brakes to the point where they DO start fading. For now they are well up to the task of what I can throw at them. Maybe its time I make a trip to Road America

skid542 · Post by **skid542** » Tue Nov 16, 2004 8:55 pm

Superb spreadsheet. Thanks.

IronMonkeyL255 · Post by **IronMonkeyL255** » Tue Nov 16, 2004 9:55 pm

Man.......

I spent about $170 on OEM brake pads because I couldn't find any cheaper ones.......

ultrasonic · Post by **ultrasonic** » Tue Nov 16, 2004 11:57 pm

Would installing more agressive pads on the rear (higher friction), while keeping stock pads in the front, effectively shift brake bias rearward? And, it would be a "full time" shift, not just above a certain pressure.

Could this be an inexpensive brake tuning technique? I'm no brake expert, so please tell me why this would, or would not, work.

Post by **Legacy777** » Wed Nov 17, 2004 3:15 am

Brat4by4 wrote:Ok. Yeah, any rear biasing is going to help. Plus, part of the problem is my tires. So with some real tires, real brake pads, and real tires... wow, I honestly can't imagine my car stopping faster than it does now.

And I don't think I need the larger Legacy brake system they have now, yet. But who knows, as my driving skills improve (and my car velocities increase) I might start using my brakes to the point where they DO start fading. For now they are well up to the task of what I can throw at them. Maybe its time I make a trip to Road America

May want to check out this thread on nasioc
http://forums.nasioc.com/forums/showthread.php?t=664099

I posted a crap-load of info regarding the new legacy's brake setup. Subaru has really done some tweaking on that car.

Post by **Legacy777** » Wed Nov 17, 2004 3:16 am

skid542 wrote:Superb spreadsheet. Thanks.

welcome. It's sort of a work in progress. Some of the info may or may not be useful in there.

Post by **Legacy777** » Wed Nov 17, 2004 3:22 am

ultrasonic wrote:Would installing more agressive pads on the rear (higher friction), while keeping stock pads in the front, effectively shift brake bias rearward? And, it would be a "full time" shift, not just above a certain pressure.

Could this be an inexpensive brake tuning technique? I'm no brake expert, so please tell me why this would, or would not, work.

Yes you can get better rear brake pads which will create a shift in rear brake bias. That's been a trick auto-xers have used, as well as other racing sports I'm sure.

How much bias swing will ultimately depend on the mu (friction) factor for the stock pads and the new pads. If you knew both, you could figure out how much of an increase in brake torque you would see.

On the issue whether the increase will be all the time or above a certain pressure. The increase will be all the time. If you're comparing old pads to new "grippier" pads. The brake torque increase will however probably not be linear, because the pad mu factor normally changes some with temperature. There will more then likely be a larger change (decrease) in mu when looking at a large change in temp for the stock pads, compared to the performance pads.

I know that last part is kind of wordy. Let me know if it doesn't make sense.

Post by **Legacy777** » Wed Nov 17, 2004 5:26 am

I updated my spreadsheet to include some of the new legacy gt info I put in that thread on nasioc

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Brake Upgrade Guide....

Brake Upgrade Guide....