Swiss Cheese and the Rebar Method


Last week the coupe arrived back from the glass blaster. We knew that we were going to discover hidden issues, so we weren’t surprised to find quite a few areas with poor metal work and plenty of filler covering things up. The car had been repainted 10 or so years ago, and one can hide a lot of sins under a fresh coat of paint.

Now that all is exposed, we have plenty of Swiss Cheese holes. Behind the sunroof (where the water drains had clogged decades ago). On fenders, behind rear wheels, doors and more.



The Rebar Method

What we were not prepared to see was rebar. Inside the driver’s front wheel well was plenty of fiberglass, reinforced with rebar and more fiberglass. Scott, our faithful blaster said that in his years of blasting restorations he has never discovered rebar as a structural component. I never thought that Home Depot would have many parts for auto restoration.

As bad as this is, we already knew of a lot of repairs in the strut supports, so we won’t let this beat us down too much. We will source new metal and get it cleaned up properly. It’s too early to get beat down yet.


Battery Module Placement

Now that things are finally clean and free of grease, we took an opportunity to dry-fit some foam models of our Tesla battery modules. Through our research we know that we can run these units vertically with very little gap between them - as little as 3/16” if we configure mounting rails just so and our wiring setup doesn’t push the bolts to the next module. In this photo, we have 9 units across the engine bay (but we may need to reduce this to 8 to allow a bit more room for reality). The far left and right unit are sitting on frame rails, but the center units are extremely low in the bay.

We then add 2 more where the radiator sat, and finally up to 4 more can stack flat on top of the main cluster of modules. This gets us 14+ all in the engine bay, and the bulk of the weight will be much lower than the engine weight which sat much higher in the compartment.

To keep the center of gravity the lowest, we would prefer not to stack that last 3-4 modules on top of the base cluster. One module does fit under the rear seats with some modification to the tunnel. We would have to perform a lot of modification to get one or two where the transmission sat. Finally we could easily get 2 or more in the trunk, but we prefer to not add the weight back there, as the drive unit is as much weight as we like back there.


Raspberry Pi for dessert

We picked up a Raspberry Pi with dual isolated CAN Buses and a 7” touchscreen to begin programming our control system. This system will control most of the basic functions of the car from blinking the turn signals, setting the interior to 70 degrees and more. It won’t perform critical motor and braking control, but it will push to the Tesla control unit what preset we are running (i.e. Standard, Sport or Valet modes) I will describe more of these details in a future post.

Well, that’s all there is to report this time around. Happy New Year!


Paul Dexter3 Comments