QUOTE(yeahmag @ Jan 26 2023, 05:59 PM)
QUOTE(slivel @ Jan 26 2023, 03:47 PM)
QUOTE(yeahmag @ Jan 26 2023, 02:23 PM)
QUOTE(slivel @ Jan 26 2023, 01:59 PM)
We couldn't get the camber that we needed on my car and solved the problem by welding up the hole on the inner suspension mounting ear and redrilling for more camber. I think my tub was slightly tweaked.
I've considered that, but was scared of putting the stress further out "on the lever" of an already stressed part. Seems to me like taking the same approach Chris has with a bulkhead and rotating the section to increase the static camber is pretty safe...
When you change the shim stack, you are departing from the plane of the surface of the inner mounting ear are you not? In my case the tub was tweaked enough that the toe was also difficult to get set so when we welded up the hole we applied some extra metal on the one side to compensate for that as well. In a perfect world, the horizonal and vertical component of the face of the inner mounting ear would describe the factory toe and camber of the rear wheel as the pivot shaft runs perpendicular to it. Any change to the angle will necessarily put some stress on the movement. With rubber bushings it is well within the ability to handle it but when you go to something less compliant there will be stress.
While I'm not sure I completely follow all of this, I do have the inner ear scabbed and I run the Rebel Racing Teflon rear bushing kit. One option I can do without much negative consequence is to relocate the hole on the outer adjuster up and forward. It wouldn't be much of a gain, but it would be some. I'm guessing I can use the shims as a mm-to-degree reference for the estimated gains.
If you are setting this up for track work, I recommend removing the rear spring and letting the trailing arm run through the normal travel. While doing this look at the outer camber /toe adjuster which should not be tightened down. Also look at the inner ear and see where the neutral position is for least tension. Then try to set the alignment settings that you want to end up with and it will become obvious where you need adjustment. You may be able to get everything you need on the outside, but I was not able to on my car necessitating some modification of the inner point. The precision of 70's vintage car building in the 914 left a lot to be desired. Tubs were not built to today's standards, and they do flex and rust /corrosion plays a factor.
I use and am a big fan of Tangerine Racing reinforced trailing arms. With my full cage , my car is very torsionally strong. This needs to be done on a track car running 2 to 3 times the stock hp, big brakes and wide sticky tires put huge stress an everything. Good luck with your project.