Is A Rear Brake Kit Worth It?
11-22-2002, 08:04 PM
#2
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It can bring flexibility, better thermal managment and better tunability of F/R biases.
I decided to do the rear Outback upgrade (290mm vs. 266 as stock on the Imprezas). My reasons are as follows:
- Better heat dissipation to allow for pad compounds that don't have high temperature capability
- Larger diameter rotor provides more torque, which allows for lower coefficient of friction pad materials to maintain the same overall torque or higher friction materials to add a bit more in the rear. Using lower friction materials with lower max temperature limits, you will tend to spend less money on pads. They also tend to be more rotor friendly, which can lead to less money on rotors.
- A corollary of the above two is that I would have more control over F/R bias with pad compounds. Typical front compounds will require higher friction and high temp requirements (as I am using stock sized front rotors). This means to maintain similar F/R balance you'd have to use higher friction materials, but by increasing the diameter 10%, you can use the higher friction materials for more rear braking or medium to low to maintain ner stock bias. For instance, at an autocross, you may WANT extra rear bite to help get the rear moving a bit at such (relatively) low speeds, while at the track this can be a big liability.
- The Outback upgrade is cheap (<$300 including pads) and completely uses Subaru parts.
If you are looking at a rear 2 pot or 4 pot option the you would add to that the stiffer calipers. I was basically looking at overall flexibility with respect to future mods, and I believe I have achieved that.
I decided to do the rear Outback upgrade (290mm vs. 266 as stock on the Imprezas). My reasons are as follows:
- Better heat dissipation to allow for pad compounds that don't have high temperature capability
- Larger diameter rotor provides more torque, which allows for lower coefficient of friction pad materials to maintain the same overall torque or higher friction materials to add a bit more in the rear. Using lower friction materials with lower max temperature limits, you will tend to spend less money on pads. They also tend to be more rotor friendly, which can lead to less money on rotors.
- A corollary of the above two is that I would have more control over F/R bias with pad compounds. Typical front compounds will require higher friction and high temp requirements (as I am using stock sized front rotors). This means to maintain similar F/R balance you'd have to use higher friction materials, but by increasing the diameter 10%, you can use the higher friction materials for more rear braking or medium to low to maintain ner stock bias. For instance, at an autocross, you may WANT extra rear bite to help get the rear moving a bit at such (relatively) low speeds, while at the track this can be a big liability.
- The Outback upgrade is cheap (<$300 including pads) and completely uses Subaru parts.
If you are looking at a rear 2 pot or 4 pot option the you would add to that the stiffer calipers. I was basically looking at overall flexibility with respect to future mods, and I believe I have achieved that.
11-22-2002, 08:08 PM
#3
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2 ways of looking at it. for general tooling around town, etc, no. If you do a significant front upgrade and dont adjust the rears also, you will shift the proportion of the braking which may adversely affect the balance of the car during braking, but in general isnt huge. you can get a different proportioning valve to replace the stock one and accomplish this. If you are only doing a sti 4 piston upgrade or pads and caliper upgrade to the front, the overall difference isnt too much. If you are putting the massive cobb/aps 14" rotors with huge 4piston caliper kit up front, its a big deal.
I have the wilwood kit front and rear and its a HUGE improvement over stock, at the track I dont have to worry about the rear brake pads fading or melting etc, and it does give more total braking power. cost wise, I chose the wilwood f+r kit over the brembo front only kit at about the same cost because of the fact it would be a better balance for the track, and i've not been sorry.
if you do upgrade, definately get some Stainless lines and motul 600 fluid
I have the wilwood kit front and rear and its a HUGE improvement over stock, at the track I dont have to worry about the rear brake pads fading or melting etc, and it does give more total braking power. cost wise, I chose the wilwood f+r kit over the brembo front only kit at about the same cost because of the fact it would be a better balance for the track, and i've not been sorry.
if you do upgrade, definately get some Stainless lines and motul 600 fluid
11-22-2002, 09:20 PM
#4
I have the rear two pots on my RS right now and boy does it work really well. Like the brake balance could not be better. But to get it installed is the pain. You need to have the hubs pressed out. But right now the car feels stable under hard braking and I have no fade at all.
11-25-2002, 10:06 AM
#7
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Originally posted by ImprezaRSDriver
I belive that Wilwood also has a 4pot rear setup for the WRX as well. That is 20 pistons for stopping.
I belive that Wilwood also has a 4pot rear setup for the WRX as well. That is 20 pistons for stopping.
11-26-2002, 10:02 AM
#10
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http://www.altasports.net/subaru/brakes/WILWOOD.htm
About 2200 for the 6/4 Wilwood setup.
In response to the question of this thread - yes. I think Concillian summed it up quite well. On my Legacy wagon I am running the same setup Subaru puts on the BH GT-B. 294mm front 290mm rears - both vented.
k.
About 2200 for the 6/4 Wilwood setup.
In response to the question of this thread - yes. I think Concillian summed it up quite well. On my Legacy wagon I am running the same setup Subaru puts on the BH GT-B. 294mm front 290mm rears - both vented.
k.
11-26-2002, 12:37 PM
#11
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Originally posted by Kobayashi
http://www.altasports.net/subaru/brakes/WILWOOD.htm
About 2200 for the 6/4 Wilwood setup.
In response to the question of this thread - yes. I think Concillian summed it up quite well. On my Legacy wagon I am running the same setup Subaru puts on the BH GT-B. 294mm front 290mm rears - both vented.
k.
http://www.altasports.net/subaru/brakes/WILWOOD.htm
About 2200 for the 6/4 Wilwood setup.
In response to the question of this thread - yes. I think Concillian summed it up quite well. On my Legacy wagon I am running the same setup Subaru puts on the BH GT-B. 294mm front 290mm rears - both vented.
k.
It doesn't appear that the Legacy Conversion will provide bigger calipers.
11-26-2002, 01:12 PM
#12
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Originally posted by Lobster Man
I'll probably go with this setup although I am more of a fan of the StopTech's.
It doesn't appear that the Legacy Conversion will provide bigger calipers.
I'll probably go with this setup although I am more of a fan of the StopTech's.
It doesn't appear that the Legacy Conversion will provide bigger calipers.
The stock WRX rear rotor is 266x10mm. The 2000+ Legacy upgrade("H6") uses the stock rear caliper on a taller caliper bracket and squeezes a 290x10mm rotor. The GT-B setup I have uses a bigger single pot caliper, a wider and taller caliper bracket and squeezes a 290x18mm rotor. This is the 2pot rotor.
k.
11-28-2002, 02:43 PM
#14
Registered User
Join Date: Nov 2002
Location: Sunnyvale, CA
Posts: 30
Car Info: 2K2 PSM WRX WGN
According to this article on Stoptech's site, they think rear
break upgrade isn't really necessary if you use their system.
http://www.stoptech.com/whitepapers/...tter120601.htm
break upgrade isn't really necessary if you use their system.
http://www.stoptech.com/whitepapers/...tter120601.htm
11-29-2002, 12:31 PM
#15
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I'd imagine it would be wasted on a car that was only used for street driving. After all most of the braking work is done with the front brakes and a upgrade there would give you the best results for your money. If you are into track events and your car is going to see some extreme braking situations on a regular basis then maybe its your thing. I just don't see it being worth the expense. An upgrade from a Outback for the rear brakes would be a cheaper alternative for a daily driver.