In a previous post the muffler assemblies were tacked together. The next step was to extend the tail subframe to support the muffler assemblies, bumper and diffuser (the latter two are still in the conceptual phase). The main subframe is fabricated from 1” OD 4130 and the new extensions are made from 1/2” OD 4130 which is difficult to bend with a manual tube bender. To facilitate prototyping, I purchased a coil of 1/2” aluminum tubing. It’s inexpensive, easy to straighten with the right tool, easy to cut, easy to bend and simple to recycle when done. Once the subframe extension was prototyped in aluminum it was replicated in 1/2” 4130 and welded to the 1” subframe.
Muffler assembly resting on 3D-printed supports sitting on top of a motorcycle jack
The next step was to figure out exactly where the mufflers would be positioned. I 3D printed two brackets to support the bottom of the muffler assembly and placed them on top of a motorcycle lift sitting on a cart with lockable wheels. Which, combined with the car lift, made it easy to position the muffler assembly exactly where we wanted it and quickly move it to tack something without worrying about dropping the assembly on the floor.
Vibration isolator (top left), 0.187” titanium tab (top middle), 1/8” 4130 tabs (bottom left), 3D-printed muffler supports (right)
I opted to hang each muffler assembly via three vibration isolators. To accomplish that, I designed and laser cut three different 4130 tabs to weld to the 1/2” sub frame and three copies of a titanium tab for the muffler assembly. Note that in the pictures below many areas were just tack welded when the pictures were taken.
The next step is to replicate everything on the right side and finish weld all of the seams.