I created this velocity stack based on pictures I found online. It mates with a K&N air filter (model RU-4410 or RU-2990)
There are left and right variations of the velocity stacks. I also added a flange at the end of the stack to the neck of the filter sit perfectly.
Back of the stacks are hollowed to save filament material
I printed mine in Polycarbonate (PC) which should withstand the gasoline and engine temperatures.
Bolts are based on the stock air filter bolts.
Printed at:
0.20mm with supports for the stacks
0.16mm without supports (with brim) for the bolts
Hope this helps someone!