I’ve been through a bunch of iterations on the cooling system. At this point, I not using any of the heating or cooling parts supplied by Superlite nor the LS7 mechanical pump. During the process the following diagram has been through multiple iterations and hopefully this is the final, final, final version — LOL.
As I’ve previously mentioned, the single best resource that I’ve found on automotive cooling systems is this article on 4x4 Pirates. While it doesn’t mention remote electric pumps or mid-engine cars, its content is directly applicable.
My current plan is to not run a thermostat, but I have ensured that there is space to add one if needed. The LS7’s mechanical pump places the thermostat on the inlet side of the engine for reasons covered in the aforementioned article. While placing it on either side would work, fitment works better for me on the inlet side.
The one feature that I’m going add that isn’t covered in the article is a coolant swirl pot. Apparently these are very common in race cars to separate air bubbles. The Raver SL-C has one and the following excerpt is from Engineer to Win:
I still consider the water system de-aerating swirl pot (as described in PREPARE TO WIN) to an absolute necessity on any racing car... I strongly prefer to make the header tank non-circulating as shown in FIGURE [184']. In this case I run a good sized hose (say, dash 10 or dash 12) to the inlet of the pump simply to facilitate the filling of the system. If, for whatever reason, the header tank is part of the coolant circulating system then the size of this line must be severely restricted (say 1/4" ID) in order to prevent any sizable portion of the coolant from following the path of least resistance from the header tank to the water pump, bypassing the radiator(s) entirely.
—Carroll Smith
Do I need one? No, but I needed to merge the two -12 lines from the engine into the the 1-1/2” tube that runs sown the left side pod and the swirl pot serves that purpose. In addition, continual de-aeration can only help things considering that 2% air in the system results in 8% less heat transfer, but 4% air results in 38% less!
The swirl pot is made from 2-3/4” aluminum tube and I decided to dome the top to promote air bubbles escaping… plus it looks cool;-) I purchased a 4” half sphere and while I was pondering how in hell I was going to clamp it so that I could cut the tip off, Abe tack welded it to a scrap 4” tube which made it easy to cut on a horizontal band saw. Once the cut was cleaned up, I needed to mark the exact center. To accomplish this, I put some layout dye on the middle, stood it on end against a vertical surface, measured the OD on a digital height gauge, divided that number by two, reset the gauge to that number, and rotated the cap while marking it with the foot. Given that all of the lines intersected, I knew that I had the center — or as close as possible given that the OD wasn’t perfect.
I used a hole saw to cut the bottom and the arbor created a hole in the middle. Rather than fill the hole, I decided to enlarge it and add a bung for a drain. I ground the back side of the weld bungs until they were flush with the inside surface. I’m still waiting for a couple of parts, but it’s almost ready for Abe to weld together.
