06-07 WRX 4 pot brakes... FIT!

[sowise]

Originally Posted by SVX_MY_BABY

I need to do new callipers and rotors all around and my rear plates have rusted away.

Any new developments?

What is the wrx calliper part number for the rear? Year?

Would you use wrx rotors?

Any negative side effects on brake balance if you only do the rear with wrx?

Check this auction for year make and model info, I have the same rears but you would need to change the backing plate to mount the rears. I did my initial with the stock rotor and didn't see any issues but I am working elsewhere and having done the rear bearings and final fit with new rotors yet.
http://cgi.ebay.com/ebaymotors/Subar...#ht_1004wt_939

plus a set of fronts will cost more than my whole parts car so that portion is just on hold for now.

[Crazy_pilot]

Originally Posted by SVX_MY_BABY

Any negative side effects on brake balance if you only do the rear with wrx?

I'm going to guess that you'll have less effective braking in the rear due to the larger fluid volume requirements of the WRX calipers. However, that's just an educated guess.

[zavikan]

I just posed this problem to allexperts.com

They seem to be a pretty awesome site with some real deal expert advice. I've used them many times for other things.

Just posed the question to some race fabricators asking if there WAS a way to cut the mounting brackets and reattach them in an uncompromising way.

Cause it honestly sounds scary to me, but then again, im no expert... maybe it can be done?

[zavikan]

I've got some interesting news. This is what I asked, and the reply. Also his credentials.

Expert: Dan Liddy
Subject: Cutting of Brake mounting points: SAFETY
Question: Asking you in the race world b/c of your fabricating experience.

The Subaru SVX. great little rare sport coupe of the 90's. Problem was it was plagued by small legacy brakes. There are 1 or 2 BBK's available, but they have had limited success, and astronomical costs.

It has been discovered that modern WRX brakes will mount up the rear w/ no modification.

The front WRX calipers also mount, but bring the braking surface outward so that a stock rotor is not large enough in the diameter. No rotor can be found to fit the new required specs.

It has been suggested that the mounting points on the wrx caliper brackets to be cut off, and then reattached after cutting out a short section of the bracket.

My question:

Is it possible to do this w/o compromising the safety of the bracket? Welding? some other method? failure would result in catastrophe of course, so safety is of course the ultimate concern.
Answer: Hi James:

I'm not familiar with the exact nature of the Subaru front spindle assembly but your answer is a qualified yes.

First: your welder should be highly experienced, and able to run a neat and very even weld bead.

Second: The parts to be mated should be ground to provide a deep "V" so the welding will penetrate all the way through the bracket. If possible, they should be welded from BOTH sides, and both sides should have the "V" ground in them beforehand. Your welder should clamp everything firmly in place before starting, and leave it clamped until it has cooled naturally.

Third: I would suggest that after the weld is cooled completely, it be re-heated with a torch and annealed to relieve any internal stresses. Do this with a large 'rosebud' torch tip and heat the entire assembly but concentrating on the welded area, bringing it to a very dull red, then allowing it to cool naturally. NEVER cool welded metals with water, it causes brittleness.

Be sure to measure everything VERY Carefully before, during , and after each phase of the job. It should be alright. and quite safe. However when you start using it, inspect it carefully after every on track session until you're confident it's OK. The slightest crack should be investigated. Done right , it should last indefinitely.

Good luck

Dan Liddy
Sarasota, Florida
Dan Liddy
S

(Listed on his bio page)
Expertise
Anything concerning race cars, 20 years competition experience, Senior Competition Driver Instructor , car builder, mechanic, welding, fabrication, tuning , engine modifications, set up, suspension design. Specializing in Datsun/Nissan products. Please submit questions about RACE CARS ONLY. No street cars, no video game scenarios Thank you.
Experience
I have been racing for 20 years, I have been the Central Florida SCCA Regional Championship points for 5 years running, and won the championship in my class 2 times. During my first start in the 60's I won many solo awards and the State Championship Drags. I serve as a senior instructor for SCCA, and have taught in Mercedes AMG events at Daytona, and Dodge Viper Days at Sebring International. I have been in the thick of the competition for all of my career. At one time or another I have driven race cars at speeds nearing 195 MPH. It's quite a ride !


Honestly guys, I think he's right. While I would never do the job myself, I would NOT mind taking them someplace that I deemed experienced enough to do it.

Thoughts?

[sperry]

My thoughts are that if you're going to start down the road of fabrication, you might as well upgrade the entire front spindle/hubs along with the brakes, like this:

http://www.subaru-svx.net/forum/showthread.php?t=53570

It was the discussion about how the STi brakes almost but don't quite mate up to the SVX spindles that started me down the path of comparing the SVX and STi spindles to see if the STi ones could be used. Not only do you get away without having to rely on a pro-quality weld, you also get the much better STi unit bearings.

But the side issue is that it ends up being just about as expensive as getting a BBK custom made for the SVX, which is really the "correct" way to go about it. Just use Willwood or StopTech calipers and get the proper offset on the mounting bracket that adapts an STi caliper to an SVX hub. That's the least intrusive way to get it done... but it's also one of the most expensive.

[zavikan]

There are members here with the wilwood BBK. One needed pads and rotors and it cost more then $1000, so they actually downgraded to save the costs.

Said it before... I think spending big money on a part is ok if its meant to last the life of the vehicle. When its something like rotors that are a fairly standard replacement item...I would rather spend FAR less then half that cost on something explained in this thread....

I just read the brute force thread....There is a big difference in $$$ and replacement $$$ and installation $$$....for this method then what you went through... and still have yet to solve, mind you. Taking these calipers and modifying the bracket is supremely cheaper not only initially, but over all. Yours in the end 'may' be better, as it has other upgraded components, but are the costs better spent elsewhere? Taking parts from other Subarus is a good idea, b/c as they get older, they can be found for cheap money.

As far as cutting and rewelding the brackets, the VERY first thing that came to mind was safety. But in all honesty, There are plenty of people who do full custom jobs on cars and cut/reweld bits to fit right...from hack-slash to professional. All the Hot Rodders out there aren't running w/ bolt on bits. I trust that rewelding brake brackets can be done in a way that is NOT hack/slash and is very safe. I would also stipulate there is no way in heck I would trust any welder to do it. I'd take it to an experienced custom fabricator/race shop to have it done, overstating my concerns for safety while I was at it.
James

[SilverSpear]

Originally Posted by zavikan

There are members here with the wilwood BBK. One needed pads and rotors and it cost more then $1000, so they actually downgraded to save the costs.

Said it before... I think spending big money on a part is ok if its meant to last the life of the vehicle. When its something like rotors that are a fairly standard replacement item...I would rather spend FAR less then half that cost on something explained in this thread....

I have not fully read into the brute force STI brake thread, but I was under the impression that it was a bit of a hack and slash....

James

Sorry but I am still not convinced that stock front used STi brakes modded to fit SVX are worth $2k.

I would contemplate potential BBK options and see which is the closest to SVX or would require minimal modding to fit, sit like a hawk on the related board and wait till someone offer a decent set for sale. This is just me..

[zavikan]

Silver: modifying caliper brackets to sit on the SVX is certainly less then $2000....


Purchase calipers...modify bracket... buy brake pads. thats it. everything else is original SVX.

[sperry]

Originally Posted by zavikan

Silver: modifying caliper brackets to sit on the SVX is certainly less then $2000....


Purchase calipers...modify bracket... buy brake pads. thats it. everything else is original SVX.

What's the real benefit of swapping just the calipers? The SVX's sliding calipers aren't horrible in their design. Really the issue w/ the SVX brakes are a lack of heat capacity and poor pedal feel.

When I put the StopTechs on my car, the pedal feel got better, but not night and day better, which leads me to believe the pedal feel problem is really in the brake booster/master cylinder (I already had SS lines).

And without going to a much larger rotor, swapping calipers does virtually nothing for the brake fade that occurs after multiple hard stops. We already know the SVX's stock brakes are plenty fine for one hard stop... it's the heat soaking from track abuse that they can't take.

So really, a caliper swap alone is more of a cosmetic upgrade than anything else, unless the cost of FHI 4-pot pads is significantly cheaper than SVX pads, in which case there is the economical benefit. Personally, I wouldn't bother swapping the brakes unless I was upgrading the rotors significantly, but that's because I'm looking to get the car usable for instructing at the track since my WRX is too noisy, hot, uncomfortable, and hard to get in/out of for hauling students around in.

But I guess if you're mostly just looking for prettier brakes, a modified 4-pot would definitely look better and still look "factory". Plus you'd get a minor benefit to the larger caliper as a heat sink, but the real benefit comes from the larger rotor that you'll be giving up on.