120mm Fan Duct

Lenovo Legion T5 – Top Exhaust Fan Air Duct with RAM Clearance

This air duct was designed for the top exhaust fan in the Lenovo Legion T5 to improve internal airflow control without relocating the original fan position.

The purpose of the duct is to guide warmer air from inside the case more efficiently toward the exhaust fan, while preventing the exhaust from pulling fresh intake air directly from the front intake fan.
The angled internal wall also helps redirect incoming airflow downward toward the CPU cooler area, improving separation between intake and exhaust air paths.

RAM clearance was a key design constraint.
The model therefore includes a cut-out section to avoid interference with installed memory modules.
Both the standard version and a mirrored variant are included to support different mounting orientations and hardware layouts.

I had difficulty finding an existing duct that matched these specific airflow and clearance requirements, so the remaining geometry was designed from scratch.
The model is shared in case it can be useful for others working with similar case airflow challenges.

Printing considerations

• Use a filament suitable for elevated temperatures inside a PC enclosure

• I printed the part in PETG, mainly because of its better heat resistance compared to PLA

• PETG may not be the optimal long-term material choice, but PLA is strongly discouraged due to the risk of softening or deformation

• Material choice should be evaluated based on your system temperatures and airflow conditions

Included files

• Full duct model

• RAM-clearance version

• Mirrored version

This design is intended for users who want to improve airflow separation and exhaust efficiency without modifying case structure or fan placement.