CNC control arms

[Kershaw]

So SAS parts posted this thread and I contacted him about it. He said he can make the control arms for IXs. That's great news to me. CNC should be lighter and I'm a fan of making anything lighter on the front of the IX.

So my question is, is there any dimension we can change on the control arm that might help performance? This is pretty much way beyond me, so I'm be looking at you Nando or Nisse or other equally knowledgeable IX gurus.

[2002tiiguy]

I think the best improvement you can really get out of the ix is the lightness, you can add caster with m3 front cabs and you can add camber with the adjustable strut mounts (dont recall who makes ones for the ix, i think ground control) unfortunately, having the axle in there limits the geometry change, not sure how far you can push the wheels out before you run into problems with the cv joints coming out. Like you said, nando and nisse might have more insight into this. Personally, I would leave the geometry alone, if the axles are completely straight while you arent turning, you reduce the wear on the cv joints to practically nothing. (would still be cool to have cnc arms) lol

[The Dark Side of Will]

iX control arms aren't flat. I'm not sure about the RWD arms. I'd be *VERY* careful with that design, as using it in an iX would put the ball joints at an angle when the car is sitting still. They might not have enough angular range of motion left over to take a large bump. If the edge of the ball joint cup makes hard contact with the side of the ball joint shank, the shank could eventually break off... that's a bad day.

[nando]

That's a good point. I'm not sure even RWD arms are "flat" - I'd imagine they all have some angle to them at the balljoints. It wouldn't be too hard to make them that way, but it looks like he's taking a piece of plate and using a waterjet or something. Hard to tell from the pictures if they are flat or angled though.

A plate is really strong along the direction it's rolled, but in the through-thickness direction, it can delaminate. The loading on a control arm is pretty dynamic and I question wether they've done any engineering on these things, so I'd be a bit wary. Maybe they have - probably worth asking about that before spending a bunch of money. FEA analysis is a must on something like this.

It would be really cool though. The stock control arms are very heavy - but that's because they are also very strong. Another place to save a lot of weight would be the CV shafts and strut tubes. Carbon Fiber shafts and maybe billet aluminum strut housings/knuckles, that would save a good deal of weight.

[stonea]

Another place to save a lot of weight would be the CV shafts and strut tubes. Carbon Fiber shafts and maybe billet aluminum strut housings/knuckles, that would save a good deal of weight.

Ugh, that would be so nice, but also sooooo expensive.

[Kershaw]

He said these control arms would weigh between 4-6lbs. Quite the reduction over stock 25lbs. That's 40lbs off the front end. He also said this

"Car have original ride heght or is dropped down. If it's original LCA must have welded joint places in original angle if car have sport suspension LCA should be flat."

So I take that to mean if it's lowered everything will be fine geometry wise. He also gave me directions to measure everything which I'll do tomorrow.

[2002tiiguy]

cool, in for pics

[M-technik-3]

My concern would be public roads, and their ability to absorb impacts with out deforming. Any thought of using E30 Aluminium M3 control arms?

[nando]

Too short for the ix, also the RWD balljoints are smaller.

[Kershaw]

Dimension what I need:

http://i.imgur.com/wrisSoF.jpg

GREEN - from center to center of joint's
RED - From END of pin to center of inner joint
YELLOW - from end of pin to center outer of joint
Purple - dimension of pin and diameter
BLUE - Dimension from center of inner joint to pin line and it must be done on 90degrees angle to this line (because on photo it look's like this pin isn't in line with inner ball joint so i must know angle of this pin to correct clearance of pin in lolipop, in other wise there will be not fit corectly and do some stress and rubber would have low mileage)

Anyone want to measure this with me? We can double check our measurements against each other. I almost feel like it would be better to send him my spare control arm. He mentioned that after he draws it up in CAD, he'll send it out for MEA analysis. I don't know what that is though, I assume some sort of structural analysis.

[4x4_e30]

Awesome timing on this thread, I'll be taking one of my arms into work on Monday to reverse engineer. We have two Faro Arms and a laser tracker. I can measure the exact pivot point of the balljoint by taking multiple readings with the ball joint at different angles and finding where the centerlines meet. That's kinda hard to do with a tape measure.lol I'll be making mine out of a 4130 tubing with welded on billet sections where the spherical bearings mount.

[The Dark Side of Will]

Awesome timing on this thread, I'll be taking one of my arms into work on Monday to reverse engineer. We have two Faro Arms and a laser tracker. I can measure the exact pivot point of the balljoint by taking multiple readings with the ball joint at different angles and finding where the centerlines meet. That's kinda hard to do with a tape measure.lol I'll be making mine out of a 4130 tubing with welded on billet sections where the spherical bearings mount.

Willing to share the info? What's your output file format?
I worked with Faro trackers a couple jobs back.

[4x4_e30]

All the dimensions are taken using Mastercam/Verisurf, then I export all the lines, points, and surfaces into an iges file then the rest is built in Solidworks. Once it's in Solidworks I can save it as whatever.

After looking at the control arm design a little closer, the only reason the whole thing can't be flat is the ball joints don't have enough travel. It looks like the "ears" that the ball joints press into are offset so the ball joint is close to perpendicular to the mounting surface while in the middle of the suspensions travel, that way it doesn't max out in one direction and not in the other. Since I'm running sphericals with high misalignments it doesn't matter, my design can be on one flat plane.

I took some rough measurements with a tape measure and designed the basic concept of what I'll be building. Might add some pockets then strap the center billet section around the tube so it's fully encapsulated:

[The Dark Side of Will]

All the dimensions are taken using Mastercam/Verisurf, then I export all the lines, points, and surfaces into an iges file then the rest is built in Solidworks. Once it's in Solidworks I can save it as whatever.

After looking at the control arm design a little closer, the only reason the whole thing can't be flat is the ball joints don't have enough travel. It looks like the "ears" that the ball joints press into are offset so the ball joint is close to perpendicular to the mounting surface while in the middle of the suspensions travel, that way it doesn't max out in one direction and not in the other. Since I'm running sphericals with high misalignments it doesn't matter, my design can be on one flat plane.

I took some rough measurements with a tape measure and designed the basic concept of what I'll be building. Might add some pockets then strap the center billet section around the tube so it's fully encapsulated:

Well... since I have CMM data for the iX crossmember in order to build a crossmember to clear the E53 oil pan, we could work something out ;)

[95BMWIC]

Any update on this?