Locate and retain the engine in the frame, and provide the mounting datum the differential carriers use.
Pins passing through the engine mounting bosses and the frame. On CR26I the differential carriers mount off these same pins, which removed the need for weld-on carrier mounts on the frame and reduced manufacturing effort.
No part-specific design process is documented. The Engine subsystem design process applies: 1. Characterise the engine experimentally rather than from published data. Intake port geometry captured by pouring 2-part casting silicone into the ports, then 3D scanning and post-processing the molds. Port flow measured on a flow bench with valve lift controlled by fine-pitch fasteners threaded into a plate bolted to the head, read on dial indicators, with an individually characterised bell mouth adapted to the port inlet. 2. Measure camshaft geometry with a dial indicator rigidly mounted to the head probing the lobe surface, combined with lifter geometry to get the effective lift profile. CR26I: exhaust 180 deg ECD at 0.050 in lift, 7.95 mm max lift at 245 deg ATDC; intake 200 deg ECD, 8.67 mm max lift at 475 deg ATDC; 115 deg LSA, 150 deg overlap. 3. Measure valve spring force-displacement on an MTS Exceed, averaging multiple springs. Maximum displacement limited by coil bind at 0.9270 in. 4. Build the GT Suite model from those measurements and validate against dyno data. 5. Develop calibration on the engine test stand, then validate on track.
Turned and ground, or purchased to a standard.
Steel. From the cost report drawings and CAD: From the cost report drawings: CP2 Titanium (Engine Pin).
Fault Vault, CR26I, Design, Complete Failure. The 2026 rule change outlawing engine mounting connected to the span of the main hoop brace was missed in the frame edits and the SES, and the car failed SES tech at competition. Support tubes had to be cut and rewelded to the main hoop node at competition.
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. Engine Pin (as drawn): 19.05, 1.91, 12.98, 1.30, 62.74, 6.27, 6.35, 0.64 Source: Cost report drawings: CR25/Powertrain/Design/Y - Cost Report Drawings/Engine/Engine Pin.pdf; CR26i/Powertrain - IC/Design/Y - Cost Report Drawings/Engine/Engine Pin.pdf; CR27i/.Powertrain/Design/Y - Cost Report Drawings/Engine/Engine Pin.pdf Quantity per car, as costed: 4
Nothing in CrimsonStorage covers these yet.