Long overdue update. Turns out stuff takes way longer with a kid, but no complaints, totally worth it.
I have been making slow progress on front suspension over the last few months and am now getting some real momentum going. The overall plan here is similar to what I did on the B3 with lifting subframes, longer control arms, custom axles, fancy CV joints, and lengthening the shocks.. only more complicated because the B8 has a much more advanced multilink suspension design.
Goal: +5" suspension lift, +8" track width
First was fabricating a drop subframe. I waterjetted, formed, and welded some 4-3/8" drop brackets from the stock lower suspension mounting points then connected them with tubes to make a subframe:
Then got to work on extended lower control arms. All the stock pieces are cast aluminum which is well outside my capabilities so all the new stuff is steel. And BEEFY. Lower arms are 1" x .120" wall mild steel tube. I formed the tubes on a tube bender, seam welded them together, and welded on appropriate bushings I machined on the lathe.
New vs. Old:
One of the issues I ran into here was that lower rearward factor arm has a non-removable ball joint swaged into it from the factory. I cut one apart to try and adapt it to my fabricated arms but that wasn't possible. That ball joint also uses a unique taper which I could not find in any other off the shelf rod-end type joint. Instead I had to take another forward ball joint which mounts in the knuckle, and make it attach to the end of my rearward control arm. To do that I machined down the mounting area and cut a groove for a circlip. This is then press-fit into a receiving end I welded to the end of the control arm and held with an 1/8" thick stainless circlip.
For the upper control arms I was able to take and modify a combination of off-the-shelf MOOG parts made as adjustable upper arm for the B5 + a piece of threaded bar + a MOOG tie rod adjuster from a Kia, modify them slightly, and get these sweet fully adjustable upper arms. Mint! Alex used these same bits on his S8 and showed them to me at just the right time so he deserves all the credit for these.
Similar to the lower drop subframe, the upper arms need their own cute little drop frames. Just like the lowers, I made some drop brackets and connected them with tubes to triangulate them. For the chassis anchor on these I used an oddly shaped access hole that from the factory has this funky grommet in it; one on each side, perfectly symetrical:
I traced out the hole, then waterjetted (2) 1/4" steel plate "clamps" that are 20 mm larger than the profiled, (2) matching 1/16" HDPE gaskets, and (1) 1/16" HDPE middle gasket that perfectly fits inside the hole. These all bolt together with (9) 6mm bolts to sandwhich the chassis and give me nicest structural anchor I could dream of for this.
Next up is the shock. Originally I was planning on using some big boy shocks like King or Fox, but after a bunch or research and design work I decided that was too much of a hassle to deal with right now and abandoned that idea for the sake of expediency. I want to drive this thing! So I'm keeping the stock shocks and just cut and extended the cast lower shock mount by 4-5/8". So much easier.
I've never TIG welded to cast steel before (which I think this is). The cast material melted way lower that the plate steel so it took a good bit of heat control, but overall came out well.
Next up CV joints.
Learning from my CV joint adventures on the B3 I skipped right to the chase and used the same setup: machined aluminum adapter on the trans with an RCV Ultimate 930 plunging joint. Here are the adapters I machined:
I bolted these up, then chopped up my stock axles and some 930 axles to make some prototypes.
PROBLEM: In cycling the suspension I measured that I need a massive 2-3/8" plunge on the inner CV. The RCV joints only give me 1.1", and there is only 1" of space behind them for extra slip spline on the shaft to cheat it. Back to the drawing board.
In measuring OEM inner joint I discovered it will do 25* angle, has 2-1/4" of plunge, and enough room for 1/2" extra slip spline. Perfect! .. almost. These inner joints are non-serviceable "tripod" style CV joint where the bearing is put on the shaft with a circlip then inserted into a cup which is swaged on. To get them off I had to machine the back of the cup off so I could access the circlip to remove it and pull the shaft out.
This gets me to my end goal but there are a few definite down-sides:
1. I'm going to have to put the shaft in then weld the rear of the cut closed again
2. You can't buy just this joint if it fails; I'll have to get a whole new axle and rob the joint from it
Axles:
I welded up a pair of prototypes to test and make sure I have the lengths correct. Unfortunately I destroyed one of my stock outer CV joints in my experimenting so I'm waiting on a pair of two new ones to arrive before I can throw these in and take it for a test drive.
Tie Rods:
MOOG to the rescue again. The have a Problem Solver line which is exactly that: you can look up tie rods by length and inner/outer thread pitch which is amazing. Found a perfect set and just had to cut an inch or so of thread off the outboard ends to make them work. To correct steering geometry with the lift I pressed the steel bushing for the tie rod end out of the aluminum knuckle, flipped it, 180* and pressed it back in. The asymmetrical tie-rod ends were then swapped left-to-right as they now attach from the top rather than the bottom. This almost perfectly compensated for the change in geometry from the lift.
All assembled: (less axles)
Due to some geometry compromises we only picked up 1" of flex with the front mods:
With flares!!
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