STi brakes, the brute force way! - Page 2

Crazy_pilot · #16 03-29-2010, 09:35 PM

There was talk a while back of a Willwood BBK group buy for the SVX. As is typical of most such ventures, it didn't get very far. Group buys have a history of not going well when it comes to performance mods.

TurnInConcepts · #17 03-29-2010, 09:55 PM

edit: never mind. just answered my question by reading more closely. let me do some digging...

sperry · #18 03-29-2010, 11:36 PM

Quote:

Originally Posted by Johnybeas

interested, but what are the size differences as to trying to fit brembos or other STI brakes underneath some 17's???

sounds like a lot of work and hacking involved to make it work, we aught to see if we can't somehow get enough people together to get brembo or stoptech or another company to do a full big brake setup for the SVX. I think there are more and more of us every day who are modding for big power on the SVX

Certainly getting some StopTechs to fit on the SVX knuckles is doable. You just need to have the propper bracket fabricated, the rest of the kit would be the same as the WRX/STi kits.

But what you won't get are the fantasticly better STi unit wheel bearings. Which for most people makes no difference. But I'd like to be able to hit the track on occasion w/o baking the bearings.

As far as wheel size... I don't understand your comment. Virtually all large brakes are going to need 17" wheels or bigger. The stock STi Brembos need 17" wheels... in fact they need rather large 17" wheels, as far as spoke design goes. StopTechs come in 3 flavors for the WRX/STi... the WRX BBK uses a 328x28mm rotor (that's the version I'm putting on my SVX) and there are 332x32mm and 355x32mm versions for the STi. The 335's require 18" wheels IIRC, the other two fit under 17's.

sicksubie · #19 03-30-2010, 08:42 AM

Quote:

Originally Posted by sperry

Certainly getting some StopTechs to fit on the SVX knuckles is doable. You just need to have the propper bracket fabricated, the rest of the kit would be the same as the WRX/STi kits.

But what you won't get are the fantasticly better STi unit wheel bearings. Which for most people makes no difference. But I'd like to be able to hit the track on occasion w/o baking the bearings.

As far as wheel size... I don't understand your comment. Virtually all large brakes are going to need 17" wheels or bigger. The stock STi Brembos need 17" wheels... in fact they need rather large 17" wheels, as far as spoke design goes. StopTechs come in 3 flavors for the WRX/STi... the WRX BBK uses a 328x28mm rotor (that's the version I'm putting on my SVX) and there are 332x32mm and 355x32mm versions for the STi. The 335's require 18" wheels IIRC, the other two fit under 17's.

I could have a BBK of my choice tomorrow if I wanted, but as is mentioned above I want the STi wheel bearings....

sicksubie · #20 03-30-2010, 12:53 PM

Please keep pushing this project forward...

sperry · #21 03-30-2010, 01:09 PM

Quote:

Originally Posted by sicksubie

Please keep pushing this project forward...

I am!

In fact, I attempted to drill the slots for the knuckles to get them to fit the SVX struts. Unfortuantely, my drill press is not beefy enough and flexes too much to get a clean cut. I'd be fine if it were a straight hole... but trying to cut a little crescent-moon shape out of the side of the exiting hole just allows the bit to wander too much. I'm actually going to grab the parts and head over to the machine shop today at lunch and see what they think about making the cut.

I also ordered the reamer bit for the ball-joint, I'll probably have that next week some time. And this morning I ordered those axles from Pegdrgr, so I'll have those in however long it takes ground shipping from Portland to Reno... probably next Monday, but maybe by Friday this week.

In the meantime, I'm going to do some mock-up ball-joint adapters in poplar wood and see if I can figure out the proper location/clearance for the ball-joint to make sure I don't end up with a ton of unwanted negative camber. Much easier to cut/drill a bunch of wood mock-ups than to wear out my drill bits on steel.

sicksubie · #22 03-30-2010, 02:03 PM

Awesome...

sperry · #23 03-30-2010, 04:55 PM

Welp... knuckles are at the machine shop. They should be slotted for the SVX struts sometime tomorrow. I really wished I could have done them on my press, but it's gonna take a mill to take that bite out of the 1"+ thick flange.

Cam · #24 03-30-2010, 06:36 PM

When I slot holes at work, I use a bushing that is the same ID as the OD of the drill bit I use (+.001 for clearance on the bushing) and use a "steamboat" to clamp it to the part with the hole that needs slotted. The steamboat is nothing more than a mount for the bushing, a surface just big enough to get a c-clamp on. It has a hole for the bushing to slide into. You can line them up with a nylon "bombsight" (clear bushing with cross-hairs) or do a hand layout. The bombsight is obviously more accurate.

The bushing holds your drill bit straight and adds rigidity while drilling the second hole to create the "slot". Even on 1" thick material it is usually enough to keep the bit from bending.

Keep in mind that when drilling steel, excessively slow RPM on your drill press is much better. In the ballpark of 400-500 RPM is where you want to be. Steady, consistent pressure should be applied to the lever as you begin to drill the hole. If you can rig a "steamboat" (a piece of 2x4 with a hole in it) and get a bushing (a piece of that steel with a pre-drilled hole in it perhaps? inlaid into the 2x4, of course) you could probably slot them yourself.

This could come in handy (and cost-effective) if these particular pieces do not work out for you when they return from the shop.

sperry · #25 03-30-2010, 07:00 PM

Quote:

Originally Posted by Cam

When I slot holes at work, I use a bushing that is the same ID as the OD of the drill bit I use (+.001 for clearance on the bushing) and use a "steamboat" to clamp it to the part with the hole that needs slotted. The steamboat is nothing more than a mount for the bushing, a surface just big enough to get a c-clamp on. It has a hole for the bushing to slide into. You can line them up with a nylon "bombsight" (clear bushing with cross-hairs) or do a hand layout. The bombsight is obviously more accurate.

The bushing holds your drill bit straight and adds rigidity while drilling the second hole to create the "slot". Even on 1" thick material it is usually enough to keep the bit from bending.

Keep in mind that when drilling steel, excessively slow RPM on your drill press is much better. In the ballpark of 400-500 RPM is where you want to be. Steady, consistent pressure should be applied to the lever as you begin to drill the hole. If you can rig a "steamboat" (a piece of 2x4 with a hole in it) and get a bushing (a piece of that steel with a pre-drilled hole in it perhaps? inlaid into the 2x4, of course) you could probably slot them yourself.

This could come in handy (and cost-effective) if these particular pieces do not work out for you when they return from the shop.

That's a pretty slick idea.

But the machine shop just called me like an hour ago to let me know the knuckles are already done, I just got back from picking them up.

So I'm gonna test fit them to the struts tonight when I get back home. They look pretty good... certainly better than they were going to be had I taken the dremel to 'em.

Cam · #26 03-30-2010, 07:04 PM

dremel eh?

I love hacking stuff up with my dremel

sicksubie · #27 03-30-2010, 08:23 PM

looking forward to this... Question though.. If there is an issue with camber, why not create the adaptor to have a bend or angle in it from the point where it mounts to the control arm to where the ball joint goes in.

sperry · #28 03-31-2010, 12:18 AM

Quote:

Originally Posted by sicksubie

looking forward to this... Question though.. If there is an issue with camber, why not create the adaptor to have a bend or angle in it from the point where it mounts to the control arm to where the ball joint goes in.

Actually, due to the angle of the ball joint in the STi knuckle itself, I think the correct angle should be zero. The SVX knuckle actually does have an angle like you mentioned, but the adapter will need to be flat due to the difference between the two knuckles... which actually greatly reduces the fabrication cost/difficulty.

Note in this picture, the angle of the SVX ball-joint (left) is compensated for by the angle in the ball-joint mount. While the STi mount will be just flat because there's not angle in the ball-joint.

Besides, an angle wouldn't significantly change the camber of the knuckle. The effective length of the lower control arm does, which will be determined by the length of the adapter itself.

I just got done test fitting the machined knuckles a second ago. The struts mount up great, and there doesn't seem to be a negative camber issue the way I was worried. If anything I've got a little positive camber and some narrowed track-width. But I think once I've got a ball-joint in there, it should be pretty close to the factory position. The new concern is whether or not the strut top mount is going to max-out as I pull the knuckle out towards the end of the LCA.

Anyway, here are some pics of the test fitting. I forgot to take a picture of the slotted flanges before I bolted them up... but I'll get some when I take it all apart again later. I'll need some good pictures if I'm going to draw some templates up describing how to get the slots correct.

Here's the bare knuckle just hanging from the strut.

Here's the other side with the hub tossed on there as well.

Finally, I tossed a rotor and a StopTech caliper on there just for fun.

sicksubie · #29 03-31-2010, 10:59 AM

Like what I see so far... I am going to have to start scouring NASIOC for spindles now...

Johnybeas · #30 03-31-2010, 12:17 PM

Wow. I'm pleasantly surprised. This looks really nice. You answered all my other questions, I'm currently running American Racing Casino's in a 17 so based on my understanding from your answer I think I'll be fine.

My next question is, based on what you said the difference between the STi axles and the SVX axles does the same apply between STi and WRX?? I didn't have to use WRX axles with my 5spd conversion I just took the little splines out of the end of the axle and plugged into the ones on the transaxle. Will I need STi axles for this mod? or will mine suffice?

Also if you were to offer the modified knuckle how much would you charge a member for a kit or something???