Frame Strengthening

Last week, Neil Fraser CERTZ came and had a look at my engine mounting arrangement. I want to rubber mount the motor while hard mounting some cells in front and the inverter on top. He recommended diagonal 38.1x2.5mm roll cage tube between the suspension towers and the front corners to provide a location for the motor mounts. A structure to hold the inverter and cells will be attached to these new members too. The cells will need to be mounted such that they can break away in a crash.

The tube is extremely strong, it comes in 5.5m lengths and has a bit of flex when it's that long, but boy, when you cut off an arm sized piece, there is no give to it at all. He also recommended 3mm steel plate to reinforce the subframe where the tube joins. As conic sections are somewhat new to me, I've made up a dummy tube -- the threaded rod lets me adjust the length while I get the end profiles correct. When it's time to make the real thing, getting things right first time will be more critical. The taped on cardboard shows the shape of the spreader plates.

We also discussed putting another layer of cells in the boot and this won't be a significant problem. The cell frame will be made with 50x25x3mm angle iron and hung off 3mm C sections welded to into the boot floor/wheel arch corner. I'll probably connect it to the firewall too. I was only able to get 50x50x3 angle iron, so I may well be ripping it down with the grinder.