All great points gentlemen.Thank you. I'll try to answer the questions and give a good picture of the front end design.
GS guy wrote: ↑Sun Sep 24, 2017 6:00 am
Are you staying with the VW torsion bar design with AWD front knuckles?
No, due to the mounting of the torsion bar and differential it seemed a conflict not worth solving. Really wanted the performance of a double A arm
GS guy wrote: ↑Sun Sep 24, 2017 6:00 am
For growing your own unequal length a-arm suspension - I highly recommend getting a suspension design software package.
I am using this
Virtual Suspension Calculator to get the basics down. I have another one that includes the steering rack and drive axles. You are right, it has helped out a lot working with the variable dimensions once the physical limitations are known.
GS guy wrote: ↑Sun Sep 24, 2017 6:00 am
If you're thinking about going with an entirely new front suspension design, have a look at adapting the Subaru front uprights as a knuckle for an a-arm style suspension
I am using the Subaru knuckles, but due to their proximity the inside of the rim and to maintain a decent (SAI/KPI) I am going to mill them down (3 sides). I am going to drill anther mount hole and manufacture a bracket to hold a stud for the Del Sphere joint. This was one of my previous pictures of the knuckle to be cut down.
Knuckle.jpg
One of these will go on top with a cone spacer. Went this route because trying to fit a ball joint setup with a tapered cup would be more difficult. They are adjustable tension wise, allow 28 degrees movement and can be rebuilt.
Del-Sphere-Pivot-Joint-34-16-Left-Hand-Threads-Narrow-Mount-Style-1.jpg
Del-Sphere-Pivot-Joint-Weld-On-Roto-Joint-25-OD-1.jpg
GS guy wrote: ↑Sun Sep 24, 2017 6:00 am
Unless you're building your own spindles, you'll have to use whatever SAI is designed into the knuckles you're using. Typical I've seen for a MII style and many other spindles is about 9-10 degrees.
When I make the bracket for the upper joint I can set it to pretty much any SAI and caster. Figure if I don't like it, all I have to do i make another bracket and position the stud where I want. It looks like I will be around 7-9 degrees which based on my hub,tire and wheel selection puts me under a 2" scrub radius which is ideal for AWD cars.
Piledriver wrote: ↑Sun Sep 24, 2017 10:55 am
Cutting a strut down and installing an upper ball joint also allows you to set the SAI ~as you wish.
tireclearance2.JPG
The Suby knuckle is tall, The original strut reaches in to bolt up to the knuckle so there is very little vertical clearance to the wheel, can't mount the ball joint to the top of the strut due to the excessive length and angle of the upper A arm. It would also put the SAI / KPI too far out. It's why I am looking to trim down the upper part of the knuckle. Before I machine the knuckle I'll put all my dimensions on here to see if I am on the right path.
GS guy wrote: ↑Sun Sep 24, 2017 12:24 pm
The terminology SAI - Steering Axis Inclination is a bit confusing
They are one in the same, since kingpins aren't used on modern cars I guess they had to come up with a new term.
I was doing the same thing trying to figure out the difference, I guess if a car doesn't have a kingpin it can't have a kingpin angle. But if a car has a kingpin it can still have a steering inclination angle
I can visualize Pile's point of locating the upper BJ pivot where you want it at the top of the upright if you're custom making your own setup - could be a nice advantage being able to do that! The other "SAI" I can visualize would be caster, which is typically adjustable (front to rear) to where-ever you want it to be.
I was trying to think of a stable way to be able to move and lock the upper ball joint in different positions relative to the knuckle. It would allow caster or SAI to be adjusted before moving to the inner pivot A arm adjustments. With vertical space at a premium I figure I can slot the bracket I will make that will allow me a few degrees of camber / SAI to dial it in. Since I want caster to be adjustable without moving the inner control arm pivot points I am going to design the upper arm after the SPC style.
Adj Upper Control Arm.jpg
Every design I come up with has to remain clear of the axle and shock or push/pull rod for the shock. It has been a challenge, especially when I look at how simple the Mendeola is on my other car. The ball joints are only separated by a few inches vertically. Appreciate all the input and keep it coming, looks like I will shoot for 7-9 degrees on the SAI. My icluded angle (SAI + static camber) should be spot on. The last geometry question is the rising rate of the camber. What's considered ideal? For every inch of travel up, how much negative camber should be added. This will lock in the A arm dimensions and determine my mounting points for them. I have read some articles but many do not go into detail what good values are.
20170924_181327.jpg
Finished out the weekend clearing the body for the chassis bulkhead. Want to set it into position before welding it to the chassis. Then the front suspension that will get built on it is a go! Thanks again gentlemen for the valuable input and ideas.