STi brakes, the brute force way!

[sperry]

Originally Posted by oab_au

Sperry as you know the sensor is an inductive pick-up. The signal from it depends on the speed and strength of the magnetic field. I would say that the sensor is too far away from the rota, so the magnetic field is a bit weak, ok when the rotation speed is high, but when you slow down the speed of change is too slow to develop a good signal. It should be 0.7mm to 1mm from the rota.

Short answer, move them in closer.

Harvey.

Yeah, that's what I figured as well after thinking about it more. If the car thinks the fronts are locking up, it's likely due to lower current in the inductor, which would indicate the sensor is still too far. Then again, I'm assuming it's the fronts that the ABS is triggering on... it could be the rears, I'm sure it's a lot harder to feel exactly wheing brakes are jerking the car at <1mph than it seems... but it does feel like the fronts to me.

Anyway, since it's harder to add spacer back in than to grind it away, I'm taking baby-steps to get there. Without pulling the whole knuckle and axle off the car, I don't think I can directly measure how close the sensor is to the tone wheel. What I've been doing is just sliding a bolt in there and marking the height... so there's certainly some error introduced in my measurement that way. But I hightly doubt I'm within a mm of the rotor.

[sperry]

Originally Posted by sicksubie

ditch the ABS...

If this was a track-only car... I'd consider it. But even at the race track on a race car, ABS is nice because it prevents flat spotting a $1000 set of race tires.

For my daily driver, I'd much rather have it than not, if I can get it working properly.

[superru]

what's the update on this project? still need some machine shop fab?
shaweeet!!! nice mod man!

[sperry]

Originally Posted by superru

what's the update on this project? still need some machine shop fab?
shaweeet!!! nice mod man!

Well, I was having those minor ABS issues. So I ordered up some '02 WRX sensors last week. Over the weekend I got around to installing them (along with 6 new bolts and lock-nuts for the BJ adapter).

Unbelievably, the WRX ABS sensors are damn near bolt in. The have the exact same plug and grommet as the SVX sensors, so they pluged right in. The bracket on them isn't the same as the SVX's, but if you grab some slightly longer bolts and bend the brackets a little, they will screw down right on top of the brake line bracket.

And so far the ABS seems 100% back to normal! Works good from ~45mph on a hard stop. No more false triggering around parking lots. I just haven't been able to test it on actual slippery conditions, but I'm betting the sensors are totally compatible with the ABS control unit.

The down side of course is that a pair of new ABS sensors is like another $200 on top of a project that's already pushing the envelope of value. I'm starting to think that this mod is more expensive than it's worth unless you've got money to burn. If I had known how expensive it would eventually be, I probably wouldn't have started on the project.

With that in mind, I'm hesitant to make up a kit for this conversion. I really don't think there are many people that would be willing to drop >$2000 for this conversion, especially with all the little things that have to be handled. If it were as simple as just slapping the BJ adapters under the car, then it'd be a slam dunk... but with the need for axles, ABS sensors, slotting of the upright on the knuckle, reaming of the steering arm on the knuckle, shortening end-links, potential need to run wheel spacers, the rubbing issue at full lock I haven't sorted out (I can't find the rub, I'm starting to think that I'm maxing out the axles!). There are just so many little issues, that even with a kit, the end user is going to need to be able to solve lots of little fitment issues by the seat of their pants making this anything but a bolt-on conversion. Basically, anyone that could use the kit, is also probably adept enough to do all the fabrication themselves the way I did it.

So, unless there's a bunch of outcry and people willing to front some money to get a run of these produced, I think the smart think for me to do is just to put together a good design document outlining all the steps for someone to roll their own conversion.

[sowise]

Sperry quick question regarding this mod but it sounds like while it was expensive and extensive to do in the end though you have a set up that will be cheaper to maintain? You can pretty much order subaru parts for replacement SVX and WRX correct? With Wilwood and some of the other Big Brake kits replacement parts rotors and pads etc are not cheap to replace. Just wondering if you factored that in to your assessment of this mods value. Interesting read though! Great work too.

[sperry]

Originally Posted by sowise

Sperry quick question regarding this mod but it sounds like while it was expensive and extensive to do in the end though you have a set up that will be cheaper to maintain? You can pretty much order subaru parts for replacement SVX and WRX correct? With Wilwood and some of the other Big Brake kits replacement parts rotors and pads etc are not cheap to replace. Just wondering if you factored that in to your assessment of this mods value. Interesting read though! Great work too.

Well, I went with StopTech brakes, so I'll be ordering pads and rotors for those which aren't on the cheap side. The pads aren't terribly expensive, but the friction rings for the two piece rotors are pricey. However, they're so heavy duty, they will last a ton longer than OEM stuff on a street driven car.

Sti Brembos aren't much cheaper than the StopTechs either. But if you went with the 4-pot FHI brakes they'd be more affordable... though I can't imagine it'd be much cheaper than the stock SVX stuff.

The nicest part really is that you get the STi wheel bearings. They're not cheap, but unless you're tracking the car, they'll probably outlast the chassis. The point of this mod isn't really to make things more cost effective. It's really to get more performance out of the car.

[92 SVX]

Originally Posted by sperry

Well, I went with StopTech brakes, so I'll be ordering pads and rotors for those which aren't on the cheap side. The pads aren't terribly expensive, but the friction rings for the two piece rotors are pricey. However, they're so heavy duty, they will last a ton longer than OEM stuff on a street driven car.

Sti Brembos aren't much cheaper than the StopTechs either. But if you went with the 4-pot FHI brakes they'd be more affordable... though I can't imagine it'd be much cheaper than the stock SVX stuff.

The nicest part really is that you get the STi wheel bearings. They're not cheap, but unless you're tracking the car, they'll probably outlast the chassis. The point of this mod isn't really to make things more cost effective. It's really to get more performance out of the car.

I think what he means, and I agree with. Is your parts will last way longer then the svx oem part so while you pay a higher premium initially you only pay it once. Instead of 3-4, or more times. thus in the LONG run it could be cost effective or even cheaper.

[Johnybeas]

still interested, would love to see what all modifications are entailed.

I wouldn't be apposed to hacking away and welding and fabing some stuff to make this work.

I see the value of the costly upgrade to in the long run have more readily available parts that won't end up disappearing from shelves anytime soon

[Johnybeas]

bump...

Any progress on this??

[Johnybeas]

Originally Posted by sperry

I should be able to get a quote this week at the waterjet shop as long as my actual job doesn't get in the way.

Right now it's looking like 4 people that are interested?

Johnnybeas, Pegdrgr, sicksubie, Cam... ? Perhaps a "production" version for myself? Get a quote for 5 pairs?

once perfected if the price is right you can definitely count me in

[sperry]

Originally Posted by Johnybeas

once perfected if the price is right you can definitely count me in

Sorry for the long delay...

It's funny you should mention perfecting the design... because last weekend I figured out what my rub was, and it's not the tire on the fender.

The back of the brake rotor is able to make contact with the ball-joint adapter when the steering is at full lock, and the car is leaning on the ball-joints. It's a pretty minor rub, and I was able to hit my adapters with the grinder for all of about 10 seconds to clearance the corners away from the brake rotor, but it means I really need to revise the adapter design one more time just to round off the outter most corners.

However, I'm super busy lately with other things (getting married next month!) so I don't know when I'll have time to get the design revised. But I would like to make a run of the adapters at the water-jet place. At this point, it's looking like a run of 3-pairs may exceed the demand by 1-pair. So folks, let me know if you're interested a set of the adapters and I'll see how much they'll cost to make. If I can swing the cost, I'll try to get more than one pair made up.

[icingdeath88]

Originally Posted by sperry

Sorry for the long delay...

It's funny you should mention perfecting the design... because last weekend I figured out what my rub was, and it's not the tire on the fender.

The back of the brake rotor is able to make contact with the ball-joint adapter when the steering is at full lock, and the car is leaning on the ball-joints. It's a pretty minor rub, and I was able to hit my adapters with the grinder for all of about 10 seconds to clearance the corners away from the brake rotor, but it means I really need to revise the adapter design one more time just to round off the outter most corners.

However, I'm super busy lately with other things (getting married next month!) so I don't know when I'll have time to get the design revised. But I would like to make a run of the adapters at the water-jet place. At this point, it's looking like a run of 3-pairs may exceed the demand by 1-pair. So folks, let me know if you're interested a set of the adapters and I'll see how much they'll cost to make. If I can swing the cost, I'll try to get more than one pair made up.

Congrats on getting married. Been married 4 years and it's been great. 2nd year is the hardest. Glad to see you're working out the kinks. So what all is required to do this project and what's the total cost?

[Johnybeas]

congrats on getting married soon! I wish the best for your wedding and honeymoon. Any designs you can leave us with to tinker with while you're busy?? the discovery of the rub location seems very helpful! I wonder how much could be taken off the sides for it to still provide full stability and functionality and eliminating the rub.

[Johnybeas]

Originally Posted by sperry

You don't have an R180 w/ 4.44 gears through, do you? I wasn't planning on a 6MT swap anytime soon... and I'm running a 4.44 4EAT right now. Slapping an R180 in there would be awesome to go with a full STi rear brake setup, but I don't know that it'd be worth it since I don't think a 4.44 diff is easily found... not to mention the cost for something with no benefit over the R160 LSD at stock SVX power levels.

I think I need to do some research/comparison of the rear knuckles/hubs. Forgive me while I brainstorm:

Just like the front, I'd like to use STi rear knuckles/hubs/bearings since I believe they're all stouter. Then slap the 2-pot FHI calipers and ventilated rally brakes (P/N RST-2632 here: http://www.rallispec.com/prod_brake.htm). Those are the rear brakes I'm running on my WRX.

But those 5x114.3 rotors are for the larger hubs that mate to the R180... which means the larger e-brake. So, perhaps an option is using everything from the STi (knuckle, bearing, e-brake drum, rotors, backing plate, calipers) except use the OEM SVX hub that mates to the R160 axles, and use a machined adapter that presses over the SVX hub to make it fit inside the STi bearings.

But once again the ABS becomes an issue, since I'm assuming the rear SVX hubs have the tone wheel on them instead of the axles.

So then it looks like you can do the above, but ditch the tone wheel on the hub and switch to WRX (non-STi) rear axles... but who knows if they'll mate to the back of the STi knuckles and line up with the ABS sensors. (Which could be a problem w/ the SVX axles as well, BTW.)

So now we're back to full STi rear knuckles/bearings/hubs/e-brake/rotors/calipers, etc. and building hybrid rear axles with the R180 style outter splines and the R160 style inner splines to mate to the OEM R160 diff. Ugh.

I think in this situation, the path of least resistance is just pressing the STi backing plates on there and using the SVX knuckles/hubs/bearings/rotors under the 2-pot calipers. But that means no ventilated rotors (unless you can get the R160 sized rotors in 5x114.3 which have no reason to exist), and no upgraded wheel bearings, which makes this a mostly cosmetic upgrade since it's not like the sliding calipers are that terrible... it's really just getting some beefier rotors and bearings back there that will really improve performance.

Any progress with this dilemma??

[sperry]

Well, the car picked up a clunk in the front-end today. I thought for sure after having to swerve around some douche that decided to intentionally brake check me I must have knocked one of the ball joint adapters loose, which would bode poorly for the design of these if that's all it takes for them to loosen up. So I limped it home and took off the wheels and brakes.

Low and behold, everything is torqued down tight. No loose BJ adapters, no broken parts, no play anywhere that I can see. I thought then maybe it was the extended end-links... but those were fine too.

So, no longer fearing a control-arm failure or a wheel coming off, I buttoned things back up, and drove around the block zig-zagging back and forth. There's definately a new clunk that occurs whenever the car changes direction, plus I noticed that the steering wheel angle appears to lag off-center after a jerk to one direction or the other... so I'm thinking perhaps my steering rack has come loose? Has anyone here had that happen?

The bummer is that I was planning on taking the car to the track to instruct on Saturday. I thought I'd finally be able to check out the handling and braking of the car at speed with the new front suspension and brakes. But if I can't positively identify and repair this clunk before then... no way I'm taking it out on track.