1991-1993 Toyota Eagle MkIII

Images copyright Michael J. Fuller and John Machaqueiro
Text copyright Michael J. Fuller

The rear suspension picks up on a combination of the oil tank/bellhousing and the gearbox.   
The oil tank is cast from magnesium and is a load bearing structure with the loads from the rear suspension, in addition to the chassis A-fames, all converging.  

The MkIII’s engine was an evolution of the HF 89 power plant and mated to a March-derived 5-speed transmission via the cast magnesium bellhousing.  As common practice, the oil reservoir was integral to the bellhousing.  Steel A-frames (missing in the photo) ran from the monocoque rear bulkhead and either side of the engine to the red anodized shear plate which then attached to the bellhousing.
The Toyota 503E 2.1 liter single turbo engine wasn't installed fully stressed, instead relying on a structural cam cover (shown here) and oil pan to increase the beam strength.
For the 1992 season  (starting at New Orleans) the turbo intercooler was swapped with the water and oil coolers, moving into the left hand sidepod.  This helped drastically reduce pipe lengths leading to better throttle response.  In addition to those changes, the turbo inlet periscope was eliminated.  Instead, turbo induction came via an airbox that was fed from the left hand side intercooler ducting.

ęCopyright 2008, Michael J. Fuller