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REAR DIFFUSER CONSTRUCTION
The rear diffuser work needed to happen with the car loaded onto the 4-post lift, which was a little tricky since the under-panels were still held on temporarily with dozens of Cleco fasteners.
With the car on the lift the diffuser plane was laid out with string.
Jason gave Ryan the angle of the plane he wanted to see and that was laid out to fit the constraints of the chassis, solid axle, and rear fuel cell. A "test piece" was secured in place to check for length and vertical strake placement was planned.
Due to space constraints of the fuel cell mounting, and styling concerns from the owner, we didn't do a ridiculous rear diffuser box like we have done on other cars. What we had planned was subtle, appropriate for the rest of the aero on the car, and still effective. Ryan built these sheet steel angled mounts onto the bottom of the fuel cell mounting cage (above right).
Ryan built this in a relatively short amount of time, using some flat plate and bent aluminum sheet. It rivets and bolts together, which makes repairs easier if anything ever gets damaged.
This is by far the most subtle rear diffuser we have ever built. But it merges with the flat bottom under-panels and leaves very little opening under the car (just for the tires). The full flat bottom undertray forward will make this diffuser much more effective than just sticking a diffuser under a car with a "wide open" underside.
The final portion of the exhaust system was modified after the diffuser was in place, to better locate the exit for the volume of exhaust flow from the engine. The "tips" were flush cut at an angle that matched the diffuser plane - all we have left now is to mark that on the diffuser plane and cut the holes.
CUSTOM TRUNK HINGES
With most of the unibody "skeletonized and skinned", there wasn't any of the original mounting structure left in the rear to mount stock trunk hinges. It was time to come up with a lighter, more elegant solution.
Ryan built these flanges that mount to a piece of formed aluminum sheet, which will attach to the outer sheet metal skin inside the hidden flanges. The hardware that will attach these hinge assemblies to the outer steel skin will be hidden under the trunk lid and rear window Lexan.
With the flanges and mount built, a piece of aluminum bar was machined to fit between them, then drilled for a pin. Next up he began welding up the swing arm that will mount to the trunk lid. He used a section of aluminum bar and bent it to shape, then welded it to the piece of bar shown above that fit between the flanges. And he added a mounting flange for the underside of the aluminum trunk lid.
This is the swing arm assembly and mounting flange, which will be mounted to the bottom side of the aluminum replica 69 Camaro trunk lid.
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