One of the challenges building a mid-engine car is running all of the lines for the cooling, heating and intercooling systems from the heat-soaked engine compartment to the front of the car where there is copious cool air. The path runs alongside the cockpit so you must properly space and insulate the lines so as to not cook the driver.
The first step was to weld the 1-1/2” cooling lines that run between the engine and radiator. To mount them, I used the same billet clamps that Stephen used expect that they no longer sell them with the rubber installed — 1/8” self-adhesive rubber from McMaster solved that. To get the tubes low enough to clear the control arms, the clamps had to be machined to accommodate the weld bead and floor plate. The lower mounting holes on the backside were also moved up to clear the weld bead. P-clips would have been a lot less work!
One of the brackets
Once the body is painted, the windshield is installed and everything is sealed tight, I never want to take the body off. The only way to achieve that is to ensure that nothing in the side pods will need to be serviced. That’s why I tossed the super-trick heater control valve plate I designed and I had Abe weld shut all of the bulkhead holes that I had drilled in the monocoque. So, how do you plumb everything with no connections and no bulkheads? Continuous hard lines, of course.
All of the lines that are exposed in the wheel wells are stainless steel and the ones that run inside the body are aluminum. Since it’s impossible to get coiled tube perfectly straight, that 5/8” stainless doesn’t come coiled and that some of the tube lengths were over 8’ long, I ordered 20’ straight pieces which had to be delivered via freight. That said, the coiled stuff is less expensive and is perfect for making templates. For example, the bends over the top of foot box are tricky to get to clear the body and if you mess up that last bend the entire piece is junk. I added three tube benders to my tool collection o handle the different tube diameters. Vintage Air sells stainless A/C weld fittings which were welded to the tubes after their IDs were machined on a lathe to fit.
To hold everything in place I designed seven different brackets and printed 3D-printed 14. The orange sleeves are pieces of insulation which are being used to properly locate the tubes in the brackets.
The tubes from top to bottom:
A/C Suction (evaporator to compressor, -10, aluminum)
Radiator Bleed (radiator to expansion tank, -4, stainless steel)
A/C Discharge (compressor to condenser, -8, stainless steel)
Intercooler (pump to heat exchangers, -10, stainless steel)
Intercooler (heat exchangers to intercooler, -10; stainless steel)
Cooling (engine to radiator, 1-1/2”, stainless steel)
The front of the foot box is crowded, but everything is serviceable. The Y-blocks are to plumb the intercooler’s heat exchangers in parallel.
The next step is to have the tubes coated in Cerakote to reduce heat transfer, slide full length insulation on and weld the ends on in the engine compartment. The 1-1/2” cooling lines get two five mm wraps of aerogel blanket. Aerogel is space-tech and I’ll talk about it in a future post.