The structure behind the roll hoop plays many rolls. It supports the engine, motor, differential, and intermediate shaft as well as the rear suspension. Getting this area accurate was important, so many waterjetted pieces were used to help line tubes up.
This small section, to be located at the far rear of the vehicle, was constructed first. The tubes were measured, cut, and coped with the saw and tube coping rig. Using the 2D jigging method from before, the tubes were lined up and welded.
Since the differential is bottom-loaded into the vehicle, no permanent tubes can exist on the bottom of the rear subframe. To avoid compromising strength against buckling, a subrame brace was added to the design. After waterjetting the two parallel plates, two tubes were cut and welded into place. Corresponding brackets were also cut to allow the subframe brace to interface with the frame.
Brackets that mount the motor, engine, differential, and intermediate shaft were also cut. These were designed to help align tubes while welding. These plates were tacked in place, but will not be welded until the components can be fit checked into their mounts. After bolting the subframe brace into position, the remaining tubes were tacked into place.
After a few measurement checks, the rear subframe welds were completed. The main structure of the car is now complete, save for a few gussets and mounting brackets.
PH-571 