Subaru Impreza GC8 & RS Forum & Community banner

1 - 17 of 17 Posts

·
Registered
2009 Legacy Spec.B
Joined
·
299 Posts
Discussion Starter #1
I was toying with the idea of getting some slotted rotors (from searches drilled rotors don't seem to work well on street).

I don't want to spend the money to upgrade the brake caliper system though.

1. Would getting slotted rotors and brake pads to match them stop the car better?
2. If so what are some GOOD rotor and pad combos out there.

I'm going to be putting on 17" superL's on but I roll with 15's steelies during winter. So i suppose this could cause problems.
 
H

·
Guest
Joined
·
0 Posts
1) Heck yeah. The slots or holes (drilled) allow gases to escape - preventing the pads from floating under hard repeated braking. My guess is that they'll also help evacuate water or anything else that finds it's way in there. Plus the stock setup is designed for longevity rather than ultimate performance. You know... they don't want to have people complain because they're rotors warped or that the pads dissapeared after 10k miles or something. :) (just my guess)
With an aftermarket rotor (better quality) you can use a better pad that will turn more momentum into heat energy without damaging the rotors.

2) dunno
 

·
Registered
2009 Legacy Spec.B
Joined
·
299 Posts
Discussion Starter #3
yeah that's what i figured.

but i think i'll come into a major problem with the winter setup. I'd like bigger rotors but i don't know what will fit under the 15's.
 

·
Registered
Joined
·
3,614 Posts
1) heck no! all the slots (or holes) do is aide in the disappation of heat, allowing the brakes to be used harder and more often without inducing brake fade. have you ever faded your brakes? if you haven't, then you might want to consider putting the money into something else. all slotted rotors are going to do is reduce fade, not decrease stopping distances.

2) i know paul eklund used to (he probably still does) sell some stock size slotted rotors, thus allowing you to still run your steelies. also, i've heard the mintex pads work quite well but they are definitly squeey and dirty.
 
H

·
Guest
Joined
·
0 Posts
10th - If you're running stock pads, that's true. But if you run a grippier (is that a word?) pad, you'll turn more of your forward motion into heat, and you'll stop faster/shorter.

So says me. :boxer:
 

·
Registered
Joined
·
3,614 Posts
horatio- the pad will cause more kinetic energy to be transformed into heat quicker, this is true, though how much is up for debate. slots on the rotor will only allow the heat to be dispelled more rapidlly. if you have to brake less to avoid fading, then slotted rotors could indirectly drop your stopping distance. however, if the brakes can't create so much heat to fade the system, then slotted rotors are just going to look cool.
 

·
Registered
Joined
·
599 Posts
Slotted rotors really don't help with cooling at all...they give a miniscule increase in surface area which will dissipate heat better. The true reason for slots is to prevent pad fading. When some pads get hot they "out gas", which will put a layer of gas between the rotor face and the pad which will cause it to , for lack of a better word, Hydroplane across the rotor reducing pad bite. The slots give the gas a way to ecscape as well as cleaning the pad, to prevent glazing. This also allows water to be swept away from the rotor face. Some Mintex Pads like the 1155 come pre baked to reduce this phenominon and in essence need no bedding in. Thats why when you bed in new pads you smell them...that is the out gassing that occurs at high pad temps.

Cross drilling a rotor does similar things but provides better cooling as the holes pass all the way through the rotor and its internal venting. Thus providing hot air to escape, pad gas to ecscape and water to ecscape from teh rotor face.

Paul Ecklund (Primitive Racing) does sell Brembo Slotted rotors in stock sizes for RS's. Its what I have on mine. They are great!!!

Hope that helps
 

·
Registered
Joined
·
599 Posts
you ask what the best pad and rotor combo is..for what type of driving?
my opinion:
fast street and some autocross, Brembo slotted rotors and metal master pads (see Primitive racing)

Fast street, lots of auto cross and some track time, Brembo slotted rotors and EBC RED pads, not the rotor warping greens, stainless lines and super blue fluid

Really fast street, full autocross and lots of track time, Brembo Slotted rotors, Mintex 1155 pads, super blue fluid, stainless lines, speed bleeders and a support bracket...
 
H

·
Guest
Joined
·
0 Posts
STiShawn said:
Slotted rotors really don't help with cooling at all...they give a miniscule increase in surface area which will dissipate heat better. The true reason for slots is to prevent pad fading. When some pads get hot they "out gas", which will put a layer of gas between the rotor face and the pad which will cause it to , for lack of a better word, Hydroplane across the rotor reducing pad bite. The slots give the gas a way to ecscape as well as cleaning the pad, to prevent glazing. This also allows water to be swept away from the rotor face. Some Mintex Pads like the 1155 come pre baked to reduce this phenominon and in essence need no bedding in. Thats why when you bed in new pads you smell them...that is the out gassing that occurs at high pad temps.

Cross drilling a rotor does similar things but provides better cooling as the holes pass all the way through the rotor and its internal venting. Thus providing hot air to escape, pad gas to ecscape and water to ecscape from teh rotor face.

Paul Ecklund (Primitive Racing) does sell Brembo Slotted rotors in stock sizes for RS's. Its what I have on mine. They are great!!!

Hope that helps


That's what I was trying to say, you just did it better.

An aftermarket rotor is higher quality that the stock stuff, so it can run hotter without warping. The slots allow gasses/liquids/solids to escape, and the holes allow more airflow through the rotor increasing cooling. But the way I see it, the aftermarket rotor's main benefit is not warping under hard use. If you use a set of those mintex pads with a stock rotor, I bet they would eat it alive if pushed hard.
 

·
Registered
2009 Legacy Spec.B
Joined
·
299 Posts
Discussion Starter #10
thanks for the info guys. I gotta keep the stock size since I want to stay in STS. I'll check into the Brembo disks.

What about pads. I will do about 10 autoX's and hopefully a track day. However, i don't want a pad that has to be "warmed up" for it to work well like i think the Reds are. How are the Mintex with this or any others?
 

·
Registered
Joined
·
599 Posts
The Mintexx 1155 and the EBC REDS are both pretty close to race pads, the mintex being more so. Both pads need some heat to grip best, the Mintex squeal alot when cold. But the stopping power of the Mintex pads is unreal!
For your application get the metalmasters from primitive, Paul sells the rotors and pads as a kit. Drop him a line and tell him Shawn Manny (STiShawn) sent ya.

I used to run the Mintex with the stock rotors, they never warped the rotors, but they chewed them up pretty fast. I used them for daily use, autocross and a track weekend at the glen...the pads were still good when the rotors were shot, I think I glazed them pretty bad due to poor brake cooling with my old winter wheels..
 

·
Registered
Joined
·
852 Posts
Mintex= good pad

EBC= only heard the worst


I'm actually running Eurorotor brake pads front and rear and they are awesome! Minor dust on both, especially with the Brembo Drilled Rotors up front. Don't be seduced by EBC pads. EVERYONE that I know that used them says they suck, create more dust than stock, and don't make a large difference in stopping power. If you want to check out the Eurotor Pads, then go www.spomotorsports.com

Graham
 

·
Registered
Joined
·
313 Posts
OK guys
I got Slotted roors from Paul Elkund And i believe i already had green stiff pads on my stock rotors for only 1000 miles max. Then i put those on with my slotted rotors and with in 500 miles i have badly warped rotors!! I am not over tightening my ligs either!! ALso the Brembo slotted rotors rsut like crazy. Looks very bad. WQHat about EBC ROTORS?>? how are they??

Please let me know., I need to buy rotors very soon!!
thanks
RICHie
 

·
Registered
Joined
·
91 Posts
I've used stockers, ebc greens, ebc reds, and porterfield R4 at the track. The greens were just as bad as the stockers as far as track use goes (but fine for the street and autox). The reds are ok for the track (nice grip, no fade), but they will ONLY last one event. The porterfields went one event at Watkins Glen with only about 1/3 of the lining gone.

Bill, for autox, stick with the stock pads. They have MORE than enough stopping power, won't over heat, cheap, and come with backing plates and grease.

--Roy
 

·
Registered
RSTi, STi V6, BRZ Turbo
Joined
·
6,318 Posts
I'll give anyone with a GC8 car a screamin deal on pads and cross drilled rotors at Stillen. Email me your phone number that you can be reached at durring the day, if you are interested.
[email protected]
 
H

·
Guest
Joined
·
0 Posts
Color me interested when my stock stuff wears out. :eek:

Otherwise... can't justify spending the money just yet. :(

Thanks for the offer!
 
1 - 17 of 17 Posts
Top