STOP! Lets talk about brakes.
08-19-2016, 10:46 AM
#1
STOP! Lets talk about brakes.
Lately, I've been doing a lot of research and learning a lot about brakes. I don't think I'm at the point of "hurr durr I need a BBK" as I've found the stock floating calipers to be adequate mostly because I am still working my way up through pad compounds. While I've been in the process of making my brakes better, I screwed them up and now I'm at a fork in the road for determining my next step.
Some background:
I started to really drive the car at 60k. Brakes were completely stock until 70k.
At 70k, I swapped in Centric Blanks and Hawk HP+ pads in the front. Everything else was untouched.
This worked pretty well. Car stopped better. Herp derp, ****'s great! (I didn't know any better) This lasted for about 45k before I took them off.
At ~115k I swapped in Hawk Quiet Slot Rotors and HP+ pads front and rear. Lines and fluid still original.
This was even better. I noticed that my balance shifted more to the rear and I liked it a lot. Car felt even better. I started to hit the track more. It was obvious that this set-up was not up to snuff. The pads only lasted 11k. It was time to pull out some bigger guns...
At 126k I swapped in WRX size Centric blank rotors and Carbotech XP8 pads front and rear. Also put in stainless steel lines, ATE Superblue fluid, and a Grimmspeed master cylinder brace.
HOLY **** THIS WAS GREAT! Admittedly, I bought the pads used with ~4k on them. Everything else was new. The WRX sizing put bigger rotors on the front without changing anything in the rear. This really upset the balance of my brakes. Got a lot of understeer with my now heavily front biased brakes. I also ran into another problem. After ~4k and 5 track days, the front pads were gone. That sucked.
At 130k with the rear pads looking untouched, I swapped in XP12 pads in the front. All else stayed the same. I didn't want to spend more money to change everything.
If I thought my balance was bad before, it's ****ing terrible now. But damn to the XP12s work well. This is where I am now.
I want to bring my bias back. My initial thought was to do XP10 front and XP12 rear. But I like the 12 so much that I want to keep them on the front. To do that, I think a XP16 or XP20 (16 preffered, but I don't think they make them anymore) on the rear would be the logical choice. Conversely, I could go back to 2.5i sized rotors and run XP12 front and rear. I don't really want to give up the bigger rotors though.
What would you do? Smaller rotors or crazier pads?
Some background:
I started to really drive the car at 60k. Brakes were completely stock until 70k.
At 70k, I swapped in Centric Blanks and Hawk HP+ pads in the front. Everything else was untouched.
This worked pretty well. Car stopped better. Herp derp, ****'s great! (I didn't know any better) This lasted for about 45k before I took them off.
At ~115k I swapped in Hawk Quiet Slot Rotors and HP+ pads front and rear. Lines and fluid still original.
This was even better. I noticed that my balance shifted more to the rear and I liked it a lot. Car felt even better. I started to hit the track more. It was obvious that this set-up was not up to snuff. The pads only lasted 11k. It was time to pull out some bigger guns...
At 126k I swapped in WRX size Centric blank rotors and Carbotech XP8 pads front and rear. Also put in stainless steel lines, ATE Superblue fluid, and a Grimmspeed master cylinder brace.
HOLY **** THIS WAS GREAT! Admittedly, I bought the pads used with ~4k on them. Everything else was new. The WRX sizing put bigger rotors on the front without changing anything in the rear. This really upset the balance of my brakes. Got a lot of understeer with my now heavily front biased brakes. I also ran into another problem. After ~4k and 5 track days, the front pads were gone. That sucked.
At 130k with the rear pads looking untouched, I swapped in XP12 pads in the front. All else stayed the same. I didn't want to spend more money to change everything.
If I thought my balance was bad before, it's ****ing terrible now. But damn to the XP12s work well. This is where I am now.
I want to bring my bias back. My initial thought was to do XP10 front and XP12 rear. But I like the 12 so much that I want to keep them on the front. To do that, I think a XP16 or XP20 (16 preffered, but I don't think they make them anymore) on the rear would be the logical choice. Conversely, I could go back to 2.5i sized rotors and run XP12 front and rear. I don't really want to give up the bigger rotors though.
What would you do? Smaller rotors or crazier pads?
08-19-2016, 12:01 PM
#2
Registered User
Join Date: Mar 2008
Location: San Leandro, CA
Posts: 3,856
Car Info: Forester XTi
I went with a full powerstop setup all the way around (rotors, Z26 pads) and they seem to give me a great combo of streetablity and autocross stopping power.
I suspect because you have to DD your car, and you track it. You are going to have to find a medium in there someplace. You may have to give a little on the track side to keep a street friendly setup.
I suspect because you have to DD your car, and you track it. You are going to have to find a medium in there someplace. You may have to give a little on the track side to keep a street friendly setup.
08-19-2016, 12:59 PM
#3
If you drop your fronts to 10's and run 12's in the rear, you may not experience a drop in happiness with the fronts because maybe the rears will be gripping more....
...but maybe not, as the rears maybe so unbiased that they even more so not get to working temp and make the fronts work even harder....
Test test test...
...but maybe not, as the rears maybe so unbiased that they even more so not get to working temp and make the fronts work even harder....
Test test test...
08-19-2016, 01:10 PM
#4
You changed a ton of things at the same time when changing sizes. Probably should have gradually changed one by one to get a feel for the differences. I'd go back to Hawk rotors of original size, test other pads there and chalk it up that you have to pay to play. Trying to get bias fixed would be a headache, where with pads you mainly have to worry about fade, wear and warping. Much easier to find a manufacturer fix there than trying out random combinations.
Want to track? Simple fact that you're likely to eat pads, tires and maybe even fluid.
Want to track? Simple fact that you're likely to eat pads, tires and maybe even fluid.
Last edited by El Wray; 08-19-2016 at 01:12 PM.
08-19-2016, 02:24 PM
#5
I went with a full powerstop setup all the way around (rotors, Z26 pads) and they seem to give me a great combo of streetablity and autocross stopping power.
I suspect because you have to DD your car, and you track it. You are going to have to find a medium in there someplace. You may have to give a little on the track side to keep a street friendly setup.
I suspect because you have to DD your car, and you track it. You are going to have to find a medium in there someplace. You may have to give a little on the track side to keep a street friendly setup.
If you drop your fronts to 10's and run 12's in the rear, you may not experience a drop in happiness with the fronts because maybe the rears will be gripping more....
...but maybe not, as the rears maybe so unbiased that they even more so not get to working temp and make the fronts work even harder....
Test test test...
...but maybe not, as the rears maybe so unbiased that they even more so not get to working temp and make the fronts work even harder....
Test test test...
One thing that lead me to the 12 is that the application description matched my car more than the 10's did.
But yeah, this trial and error **** is getting annoying.
You changed a ton of things at the same time when changing sizes. Probably should have gradually changed one by one to get a feel for the differences. I'd go back to Hawk rotors of original size, test other pads there and chalk it up that you have to pay to play. Trying to get bias fixed would be a headache, where with pads you mainly have to worry about fade, wear and warping. Much easier to find a manufacturer fix there than trying out random combinations.
Want to track? Simple fact that you're likely to eat pads, tires and maybe even fluid.
Want to track? Simple fact that you're likely to eat pads, tires and maybe even fluid.
I know stuff is going to wear and need to be replaced. But completely to the backing plate after only 5 days is too much. Pads should last longer than that. I want pads to last longer than that.
08-19-2016, 05:45 PM
#8
Jourdan. Imconfused. Or rather I want some clarification.
Are you looking to increase the rear bias? What do you want to change or increase?
I'm going to re-read your post to try to sort it out.
Are you looking to increase the rear bias? What do you want to change or increase?
I'm going to re-read your post to try to sort it out.
08-19-2016, 05:55 PM
#9
Ok.re-read it. You want more rear bias. From what it sounds like with pad wear, what you want is more rear mechanical bias. If it wasdrumbrakes, it would be easy.
With discs, it would be a caliper with a smaller piston so it would push the pad more at the same pedal travel...
Have you looked to see if you can find a subie rear caliper that mounts but has a smaller piston? Old rs? Old legacy l or ls? Pre 17 inch wheel days?
With discs, it would be a caliper with a smaller piston so it would push the pad more at the same pedal travel...
Have you looked to see if you can find a subie rear caliper that mounts but has a smaller piston? Old rs? Old legacy l or ls? Pre 17 inch wheel days?
08-19-2016, 07:08 PM
#10
When I had the smaller front rotors the bias was good.
I'm hesitant to go with smaller rears. I've been looking into larger options. I found a bracket that will is supposed to work with a 315mm rear rotor which I'm interested in but the details on it are super vague.
Since I posted this all over the place, one of the other ideas was to adjust the proportioning valve. I don't know if I can do that. Are Subaru proportioning valves adjustable? Is there an aftermarket option?
I'm hesitant to go with smaller rears. I've been looking into larger options. I found a bracket that will is supposed to work with a 315mm rear rotor which I'm interested in but the details on it are super vague.
Since I posted this all over the place, one of the other ideas was to adjust the proportioning valve. I don't know if I can do that. Are Subaru proportioning valves adjustable? Is there an aftermarket option?
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