I'm converting a former SCCA racer back to a street car. This canister is attached to the oil filler. Is it a race thing or do I still need it? Thanks.

Crankcase vapor can.
In a stock 914 6 it would vent into the oil tank and the air filter

And from the oil film all over the rear trunk, it would look like the engine was in desperate need of a vapor catch too.


PS: My solution is a bit more ghetto. Straight into a Gatorade bottle.
FYI, the bottle has a few holes drilled into the top portion that sits right next to the air filter to allow vapors to be sucked into the intake and be burned.
Any liquid oil that makes it through (usually if you overfill the oil) will settle on the bottom of the bottle.

PPS: The system *needs* a way to relieve pressure (in my case the holes in the top of the bottle).
Catch cans like the one pictured above will usually vent to the outside through a foam filter.