30 Sep 2008

A little surprising, of the comments received regarding round-versus-square tubing, all the replies were pro-round. So that answers that; the only square tubing will be where it makes sense, for attaching paneling or suspension brackets.

CAD work continues; the latest puzzle is determining how to most effectively get coolant from the front of the car to the back. My fabricator buddy, Alan, says to put the radiator in back; I’d love to but don’t trust that there’ll be decent airflow through the side radiators. There’s already some risk with the intercooler being back there but it’s a calculated risk. I’m much less willing to experiment with the main radiator, though.

For routing the coolant, the various ideas are to: run coolant through chassis tubes; run coolant pipes down the center then up and over the fuel tank; run them along the floor and under the tank; or something I haven’t thought of yet. I’m not too excited about running coolant through chassis tubes, not so much for corrosion but fear of spraying boiling coolant on someone in even a minor accident (never mind burning someone if they touch the tube.) A compromise is to run a tube-within-a-tube to both protect the occupants and isolate the heat somewhat. However, if the outer tube is on the floor, it’s only natural to want to use it structurally and to rivet the floor to it. Having an aluminum pipe inside it means the inner tube will be sitting on the top of the rivets – possibly wearing through – though I doubt that’s much of a problem. A good solution is to use stainless coolant pipe because it’s much tougher than aluminum, has much better heat-insulating properties, and it obviously doesn’t corrode.

Then there’s how to balance that requirement against mounting the emergency brake lever and shifter. The shifter is going to be extra challenging because someone (me) designed things so that there’s only about 3″ between the seats. Either the shifter has to go ahead of the seats, above them, or be made really narrow. I have an OEM Honda shifter assembly and it’s, well, huge, about 6″ x 10″. I might do a subproject and construct one from aluminum and rod-ends, which would look very appropriate in a car like this rather than a huge ugly plastic OEM assembly. We’ll see.

Like pushing toothpaste out of its tube, the problems are slowly being pushed out and dispensed with. My brother keeps nagging me about when it’s “going to metal” – when the CAD work is done. I’m going to use the plans myself to insure they make sense, dimensions aren’t missing, and that whatever I build first will be just like the one that you’re going to build 😉