Next he dummy-fitted the mount boxes and enlarged the holes to fit with them.
Once the boxes were fitted and the holes in the floor were enlarged to the proper dimensions, Zach used some all thread and nuts to hold everything inline as a jig.
Next, Zach enlarged the pilot holes to the full size and bent all the tabs on the box to serve as weld points to the floor.
Since the gaps that the welding had to fill were somewhat large due to the nature of the part, Zach used a mig welder instead of a tig welder. He skipped welded the parts to avoid overheating and weakening the thin metal.
With the welding complete, we now have some sturdy upper trailing arm mounts. Unlike the TRD parts the T3 parts solidly connect the two crosmembers of the frame in the back part of the unibody. This stiffens the weak AE86 chassis and every bit of additional stiffness will help the handling.
6 comments
Well, that’ll do it! It’s actually interesting to me how many pretty well regarded cars moved to equal length 4-link rear suspension instead of… well, many other things. Not messing with setting anything up in CAD and going through the motions right now, but are there any issues with the upper links and lower links not being in the same plane, or “maybe in theory but not really”?
They have to be out of plane if you are going to have anti-squat which any 4 link needs at least a little of.
I meant in terms of the upper links being further inboard on the axle, to be clear; a lot of the implementation I’ve seen of, for example, 4-links under rally cars the box that was added here would contain top and bottom links instead of just top.
I suspect that some of this upper link stuff was done for interior packaging like it was on the FB RX-7 but ugh dealing with the consequences of that decision.
In this case, they are in the same location as stock. The factory doesn’t do this because they want to have a rear seat.
Mike, any thoughts as to whether it’d be worth using those boxes to add chassis rigidity if you’re converting to 3 link, or is it sort of moot at that point, since you’d be permanently tying the cage to the chassis at that point to provide positive location for the middle upper link anyway?
One of these days I’ll get started on my rotary 86, I swear!
You would have to do one in a three-link conversion. Don’t do a short upper link,