You can bolt on the parts from a WRX or RS directly. Doing the rears is more important than fronts, but both is best. Contact RCSR for help.

 

For the front you need: Rotors, calipers, and caliper brackets from the donor car (RS or WRX). And pads, of course. I've seen sellers asking anywhere between $125 to $300 for low mileage WRX front kit.

My understanding is that since most of the useful braking power is achieved from the front brakes, that is the more important upgrade. Also, by the estimation of some, there is not particularly more brake torque achieved with the RS or WRX rear disc setup over the drums that you have.

If you are racing on a track, then you would have better heat dissipation characteristics with the rear rotor setup, certainly. For normal street driving, most wouldn't notice much performance difference. Rotors look better, of course, if that's what you are into.

Considering that upgrading rear drums to rotors requires the removal of the seats and carpet to access the hand brake cables, I think it's a huge pain for not much gain. For me, anyway.

I recently put WRX front brakes on my 2000 L wagon and am quite happy with the results. I waited until I needed new pads and rotors anyway, which helped me justify the cost of the upgrade.

Your mileage may vary.

Steve.

 

Forgive me for screwing that up. The rears are important to do if you do fronts, but doing them first would be pretty useless. By increasing the effective brake torque up front, you further move the brake bias up. This is bad, because it will actually increase your stopping distances. SCC put a front-only big brake kit on a project Civic (which had rear discs already) and it actually greatly increased their stopping distances. Granted, it was an extreme example considering the new rotors were 2" bigger, but the effect is the same. If you upgrade fronts, go to the matching rears. For conversion I believe you'll need rotors, calipers (duh), pads, caliper mount brackets, and maybe lines and hubs. All the stuff you need shouldn't be more than maybe $150-200 from the yard.

 

I see what you're saying, but... My point is, if the rear rotor system that you are converting to does not have more brake torque that the drum you are converting from, you are not realizing any change in front/rear bias, as compared to the car from which you get the front brakes. This of course leads to the question: are the brake proportioning valves different on Subarus with different front and rear brake set ups? I think most share the same proportioning.

I'm not an expert, by any stretch of the imagination. But since I just did brake upgrade, I have been researching it. This issue has been discussed on nasioc. Go to the suspension and brakes forum and search for "rear drum disc torque" for a couple of example threads, and much good discussion.

I'd love to hear further ideas on this matter.

Again, your mileage may vary.

Steve.

 

More brakes= better. Just do as much as you can afford.

 

The WRX parts ('02-'04) are a little bigger, so they'd work a little better. As far as brake bias, you are still using the rears to stop as long as the tires are touching the ground, but how much they are helping depends on how fast you were going and how hard you are braking. Hard stops from high speeds don't really use the rears as much as low speed, normal traffic stops. The problem lies in how much pressure in the lines going to each caliper the master cylinder is producing. It's weighted so that the right amount of torque is applied to each wheel based on the known strength of the system- which changes when you upgrade your brakes. Since the weight balance of all imprezas is about the same (coupe/sedan anyway) you don't have to think too hard if you upgrade all 4 wheels to the same standard. But if you increase your front brake torque significantly, say by more than 15%, then what happens is they overpower the rear, which causes them to lose effectiveness. This can lead to the ABS activating in the front when the rears aren't even close. The end result is less friction being created by your brakes, which means less stopping power. The other factor you have to look into is the size of your brake master cylinder compared to a WRX. Your pedal feel is going to change some, and your brakes are going to get a little more or little less 'touchy'- their responsiveness will change. This is in proportion to the changes relative to the cylinder the replacement brakes were designed with- assuming it's different at all, which it may not be.

Basically, if you're using OEM parts, you don't have to worry too much. I would recommend doing the rear discs as well as fronts, based on looks, fade resistance, and proper bias. The actual difference in max brake torque from disc to drum isn't huge, but it's enough to change the characteristics of your brakes. As far as finding donors, try the usual Subaru boards and the local junkyards. RCSR in Rancho Cordova, CA is a good place to start.

 

Generally the big concern, as far as front brakes go, is based on the fact that the engine, and thus the majority of moving mass, is in the front of the car. The reason big front brakes are so important is because when you brake the majority of force is placed on the front end of the car because of the the engine and transmission location. It isn't an accident that there is so much emphasis, generally, on upgrading the front brakes. I do agree however that it is not wise to have 13 inch vented 4-6 pot brakes in the front while keeping the 9 inch 1 pot unventilated brakes in the rear. Doing that just seems like plain neglect to me...and definitely leads to imbalance.

 

Lets revive this one, for me...

I've got a 98 OBS (front 10.1 disc, rear drum, 4-channel ABS), and I have some stock-size, drilled/slotted rotors I was planning to slap on the front.
I was simply wondering if this upgrade with new front pads would be that noticable, or pracrtical for that matter. Will slotted rotors/street-compound pads significantly increase the torque up front, or will I not run into the bias/proportion/ABS issues unless I go to a larger dimeter or 2-pot setup? I do lots of 70-80mph driving on curvy, hilly I-5 in southern oregon, so I'm expecting the increase heat dissipation and fade-resistance to be helpful. If I do the front rotors and pads as I plan, would it be useful or necessary to get a rear brake job at the same time (to compensate for any change in f/r bias)? BTW, I've already upgraded to s/s lines front and rear- What front pads would you suggest for this application?

I apologize for the barrage of questions, but I've been wondering about this for a while now and I just came across this thread... Thanks for any feedback