Does it do that much?

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.

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 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.

i just bought the wilwood six pot upgrade and i hope to leave a review of how they work on the track after testing them thoroughly anhd seeing what they can handle..... repeated 140+stops and such!!!!!!!

The Goatears
Andrew

I belive that Wilwood also has a 4pot rear setup for the WRX as well. That is 20 pistons for stopping. :eek:

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. :eek:

yep.. theres two ways of doing it.. the massive 6piston calipers with uprated 13.2 inch rotors in front with the 12.2 inch uprated rears with 4 piston calipers, - or - you can get kits that use the wilwood 4 piston caliper up front with the stock rears (such as the one perrin is selling).. go with the big setup, its soooo worth it.. :)

So, how much does this 'big' setup cost?

I am estimating from around 3-4k for the whole setup from and rear with the 6 piston fronts and 4 piston rears.

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.

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.

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.

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.

From what I understand the Wilwoods have some downside, noisy.

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.

Hmmm, interesting.

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/rear_brake_upgrade_is_bigger_better120601.htm

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.

We use the Stoptech front kit and just run a hot pad in the stock rear calipers on the stock sized rotors. Our rear temperatures never get very high and our pads wear nicely. I don't see a reason to upgrade the rears with a front setup that's properly balanced for the system.

Gary
Sheehan Motor Racing
www.teamSMR.com

I also run the Stoptech front kit, but I did upgrade the rears to the larger Legacy rotors (11.4" vs the stock 10.3"). I run Axxis Ultimates in the rear ccalipers, and this overall set-up is gret. The rear pads wear MUCH slower than the front at tracks days, and there's never been any overheating problems.

I have the StopTech kit up front on my WRX right now and I have vented rear rotors. The rear rotors that I have are the same diameter as the stock solid rotor with the exception that the setup is from an older generation Legacy. It uses a different caliper and bracket but it bolts right up to a stock Impreza dust sheild without modification.