Assembly line covering the complete intake system.
Groups the air filter, throttle body, restrictor, Wiggins clamp, plenum, tray, runners and bungs. Design Philosophies and Processes: Inherited from the Manifolds subsystem design process: 1. Build the engine model in GT Suite from measured geometry: silicone-cast and 3D-scanned intake ports, dial-indicator-measured cam lobe profiles, MTS-measured valve spring curves. 2. Use GEM3D to convert manifold CAD into GT Suite flow geometry, which cut manifold setup from several hours to about 30 minutes and let subassemblies be swapped for fast comparison. 3. Sweep plenum volume, runner length and primary length in the model against volumetric efficiency. 4. Confirm on the flow bench. CR26I plenum flowed 2.34% more than CR25 and 11.15% more than CR22 on average across 10-50 in-H2O, with testing extended to 70 in-H2O (17.4 kPa) to reach WOT conditions. 5. Prototype-test the muffler on the previous car before finalising, sweeping length (14 in and 16 in), packing density, tailpipe diameter (2 in and 1.5 in) and a diffuser-style tip against the sound limits.
The subsystem process above covers the GT Suite modelling. The older Sphinx wiki intake page adds the component-level sequence. It carries no car generation, and its stated target is a 12,000 rpm peak. 1. Choose the filter on flow bench data. Three K&N filters flowed almost identically, so the lightest was taken: the RC 2500 at 0.2 lb against 0.4 lb. 2. Package the Bosch 40 mm electronic throttle body and the mechanical throttle body, with a Wiggins clamp at the base of the restrictor so the joint can be broken for service. 3. Size the restrictor and its diffuser. Sweep diffuser length for pressure recovery, vary throat geometry and its position along the duct, and show hand calculation, CFD and flow bench results side by side. 4. Make the plenum from carbon fibre to cut weight and lower powertrain CG. 3D printing is named as the alternative. 5. Set runner length with the MATLAB wave tuning script, L = (EffectiveCamDuration * C) / (RPM * RV * 2 * 6), targeting 12,000 rpm, with fluid properties pulled from drive data.
From the Sphinx wiki intake page: - The restrictor. Everything downstream is designed around choked flow through it; the theoretical choked mass flow is 0.0769 kg/s. - Two rpm targets pull against each other. The intake is tuned for a 12,000 rpm peak, while the stated powerplant objective is more output in the 8,000 to 11,000 rpm band the gearing and the drivers actually use. - Serviceability has to be maintained or improved. The Wiggins clamp at the base of the restrictor is what that requirement bought. - Manufacturability and tolerances are stated constraints on the design rather than consequences of it.
From the Sphinx wiki intake page: - Choked mass flow through the restrictor, hand calculated at 0.0769 kg/s from mdot = (P0 * a*) / sqrt(T0) * sqrt(gamma / R * (2 / (gamma + 1))^((gamma + 1) / (gamma - 1))), where P0 is inlet pressure, a* is throat area and T0 is inlet temperature. - Restrictor CFD: energy equation on, k-epsilon turbulence, density based, axisymmetric, ideal gas. Pressure inlet at 101,300 and 300 K, pressure outlet at 12.5 kPa gauge and 300 K, with wall, axis, inlet and outlet boundaries. The page writes the inlet as 101,300 KPa; the unit on the page is wrong, the value is standard atmospheric pressure in Pa. - Runner length from the MATLAB wave tuning script, with a speed of sound calculation using fluid properties taken from drive data. - Flow bench, used both to choose the air filter and as the physical check on restrictor and bellmouth work.
From the cost report drawings: Carbon Fiber (CR25 Plenum).
None recorded. This part has no entry in Knowledge_Transfer/Issue Logging/Fault Vault.xlsx, in either Issue Log.xlsx, in CR22/Issue Tracking/Shakedown 7-15-23.xlsx, or in any design review issue list found in CrimsonStorage or Box.
Asked for on the Sphinx wiki intake page and not closed there: - Re-evaluate the bellmouth design and confirm it with both CFD and physical flow bench testing. - Evaluate the runner taper from a performance and a manufacturing standpoint, and test it on the flow bench. - Show restrictor analysis as hand calculation, CFD and flow bench results together rather than any one of them alone. - Move the plenum to carbon fibre for weight and powertrain CG, with 3D printing as the fallback.
CR26I total 1260.73 g against CR25's 1372.58 g and CR22's 1185.04 g. From the cost report drawings and CAD: 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. Intake_Assembly (as drawn): 62.47, 35.95 CR25 Plenum (as drawn): 25.40, R2.54, 313.80, 31.38, 189.28, 18.93, 90.49, 9.05 Plenum (as drawn): 26.99, R2.70, 161.92, 16.19, 313.84, 31.38, 159.21, 15.92, 92.08, 9.21 CR26 Plenum rev1 (as drawn): 317.22, 31.72, 53.985.40, 157.68, 15.77, 130.18, 13.02 Quantity on the drawing: 1. Source: Cost report drawings: CR22/Powertrain/Design/X - Cost Report Drawings/Manifolds/Intake/Intake_Assembly.pdf; CR25/Powertrain/Design/Y - Cost Report Drawings/Manifolds/Intake/CR25 Plenum.pdf; CR25/Powertrain/Design/Y - Cost Report Drawings/Manifolds/Intake/Plenum.pdf; CR26i/Powertrain - IC/Design/Y - Cost Report Drawings/Manifolds/Intake/CR25 Plenum.pdf and 5 more
Nothing in CrimsonStorage covers these yet.