The first step in mounting the afterburner was creating a Bristol Board template that would match up to the curvature of the inside of the rear hatch. By making it the same shape, I’ll be able to seal the hatch with some rubber to keep the water out.
Next was cutting out some half inch plywood to match the shape. I also made this piece of plywood extra long and tall. It’s much easier to trim the wood later than trying to add more to it 🙂
I attached the plywood to the rear bumper beam by welding in some nuts using the same technique as I did for my seat mounts. This let me double check my fit against the hatch before going further. Then I propped up the afterburner to take a look and make sure I had enough to reach the bottom of where the afterburner meets the plywood.
Next was building a mounting plate. I started off with tracing the pattern of the afterburner onto some 1/2 inch plywood and then measuring in 1/2 inch to make sure it would fit inside the fins. Basically the afterburner’s mounting plate is recessed about a 1/2 an inch from where the fins reach. So the plywood allows me to get pretty flush for mounting.
I then drilled four holes in the mounting plate and transferred the holes to the plywood. The goal is to embed nuts into the plywood so that I can simply bolt the afterburner to the mounting plate.
First I needed to weld some nuts to the steel plates. I needed to make sure the plates were rectangular so that they wouldn’t twist once I had them embedded in the wood.
I then inserted the bolts through the afterburner mounting plate and plywood and screwed them into the plates/nuts that I created. This would let me trace the plates so that I could notch out the wood.
I numbered each of the plates and marked their sides so I knew which direction they were supposed to be inserted.
I then brought out the chisels and notched out the wood for each of the plates so that they would sit flush with the rest of the plywood.
I then needed a way to embed and seal the plates into the plywood so that they wouldn’t come free. For this I cut out the same shape using 1/4 inch plywood and drilled the holes a bit bigger so that they would fit over the welded nut.
To finish it off I used some wood glue and screws to hold this 1/4 inch plywood in place and ensure that the plates would be sandwiched and couldn’t come free.
Last part was propping the afterburner back up in place and screwing it to the rear bumper plate. The afterburner mounting plate will also be sealed to the bumper plate using fiberglass to give it more strength and to water seal it.
I’m still not quite sure if the afterburner sticks out enough. I’ll have to take a look at some more photos of the actual car to see if I need to make some more adjustments.
I’ll also need to trim the bottom of the bumper plate plywood. Right now it hangs down below the body so I’ll have to trim it. Again I’ll look at some more photos to see how it needs to be trimmed.