Hold excess coolant, bleed air out of the system, and act as the overflow point to the catch can.
Uses centrifugal force from an angled, tangential fluid entry to separate air and vapour from the coolant. It sits at the highest point in the system, and because it carries the radiator cap it is also the pressure reference and the fill point.
Placement is the design: highest point in the system, with the inlet offset so the tangential entry can develop swirl.
Must be the highest point in the coolant circuit, which constrains where it can be packaged. Must accept the cap and the connections to the engine and to the expansion/catch can. From the design reports and one-pagers: Must be the highest point of the cooling system, which is the binding constraint on where it can go. Integration is needed with everything behind the rear roll hoop, and the fuel system and shifting system are the big competitors for that space.
The swirl pot does two thermal jobs, not one. It is the highest point in the system so the cooling system can be filled from it with no air left in the lines, which matters because air will cavitate and destroy pumps and creates heat pockets. It also creates turbulent flow: an offset inlet hole forces the water to swirl, which mixes the water and thins the thermal boundary layer, and a high Reynolds number is what makes the heat transfer work.
Get a tube for coolant. Weld the connection to the engine and the fitting. Weld on the coolant cap and the expansion/catch can connection. Connect to the car. From the design reports and one-pagers: CR22 build sequence with logged times: 1. Fit and weld the radiator cap assembly to one end of the 1.5 in aluminium tube (20 min). 2. Weld a rubber fitting under the cap assembly (30 min). 3. Drill out the centre of the hole to connect to the main 1.5 in pipe (10 min). 4. Drill an offset hole in one side of the larger pipe (20 min). 5. Weld the two pipes together (20 min). 6. Weld the connecting pipes to route the swirl pot back to the engine cooling outlet (1 hr). 7. Weld the outlet pipe from the stock engine (20 min). 8. Weld all seams to seal (30 min). 9. Cut the pipe to length and fit an AN-16 male fitting (10 min). 10. Weld the AN-16 fitting to the pipe (20 min).
Aluminium tube and fittings, radiator/pressure cap. From the design reports and one-pagers: 1.5 in 6061 aluminium tube, 1 in aluminium tube, AN-16 male fitting, radiator cap assembly. From the cost report drawings and CAD: From the cost report drawings: BMRS Convulated Tube (Swirl Pot Line Drawing); Aluminum (Swirl Pot); 6061 Aluminum (WSP003- Swirl Pot STL).
No Fault Vault entry against the swirl pot itself. The system it serves does have one: Fault Vault 2026-06-07, CR26I, air trapped in the cooling system from improper bleeding, with the pump duty cycle too high for air to release and PWM control not enabling until the engine was running.
Mass 311 g. From the cost report drawings and CAD: Weighed mass: 350.0 g (0.772 lb). Dimensions called out on the cost report drawings. These are the figures printed on the drawing, not a labelled specification; open the drawing itself for what each one refers to. Swirl Pot Line Drawing (as drawn): 166.56, 16.66, 128.23, 12.82, 33.02, 3.30 Swirl Pot (as drawn): 26.00, 2.60, 66.00, 6.60, 32.00, 3.20, 191.00, 19.10, 285.00, 28.50 WSP003- Swirl Pot STL (as drawn): 32.00, 3.20, 65.00, 6.50, 7.00, 0.70, 285.00, 28.50, 67.00, 6.70 Source: Subteam weight books: CR25/Powertrain/Design/Cooling/3 ~ Documentation/Cr25 Cooling Weights.xlsx | Cost report drawings: CR25/Powertrain/Design/Y - Cost Report Drawings/Cooling/Swirl Pot Line Drawing.pdf; CR25/Powertrain/Design/Y - Cost Report Drawings/Cooling/Swirl Pot.pdf; CR26i/Powertrain - IC/Design/Y - Cost Report Drawings/Cooling/Swirl Pot Line Drawing.pdf; CR26i/Powertrain - IC/Design/Y - Cost Report Drawings/Cooling/Swirl Pot.pdf and 4 more Quantity per car, as costed: 1
Nothing in CrimsonStorage covers these yet.