Last weekend I decided to dive in and get cracking on the new suspension. It was some time ago since I bought the second IRS subframe, and at some point I think I had decided to leave the current setup in there. Discussions with one of my colleagues at work had led to a very new idea - one that really need to be tried out. The basic premise of the idea is that as the torsion bar setup is being replaced with coil overs ther is a lot less torsional stress in the whole suspension, this means that the oversize side plates and general beefed-upness of the subframe was overkill.
The new idea is similar to my old idea based on the MBT Unibal set up with a ball / rose / heim jointed adjustable 'spring plate' but this time does not require the complex mounting to get the ball joint to fit into the pressing where the spring plate cover would normally sit - this is cut off leaving the end of the torsion bar. Instead of the afforementioned mount a large 'plug' is welded into the end of the torsion bar - this is bored and threaded to the correct size to accept the ball joint being bolted to it.
The ball joint has a left handed thread and is joined to an adaptor that bolts to the A-Arm which has a right handed thread via a 'turn buckle'. This gives toe adjustment to the rear wheels.
With the sideplates cut off there are two problems to address - the first one - where to mount the Coil-over - it is easily addressed by utilising the existing mounting at the rear of the car that the side plate originally bolted up to - the same place that the shock absorber would have been bolted to. The second problem (one of strength) is addressed by tying the mounting to the torsion bar with a tubular cross brace - similar to the old side plate but a lot less heavy.
So with the idea firm in my mind I set about prepping the rear subframe and getting it ready. The first thing I did was to remove the side plates - this was a fairly easy task utilising an angle grinder. Next the A-Arm pivot housings were removed - again the angle grinder was used - this time to to grind away most of the weld before finishing it off with a cold chisel - this way the minimum amount of metal is lost from the pivot housings allowing them to be reused.
The pivot housings were removed in this manner to allow them to be welded back on further inwards - thus reducing the track (width) of the rear suspension. This is necessary as the 944 A-Arms are too wide with the type of wheels that I'm using.
I'll get around to finishing the rear suspension off in a few weeks time as I have a feww more important projects to take care of first. My only issue now is that ideally I would like a narrowed front beam - anyone done this on a type 3 yet?
As usual more pictures can be found in the media gallery.
