Crankcase evac question

[MaineShark]

Here's an odd question about the exhaust-powered crankcase evac systems: do the connections have to be mounted after the collector, or can they be mounted in the individual tubes? On setups with very long primaries (like sidemount headers, for instance), mounting in or after the collector could be difficult.

Joe

 

[JohnZ]

They should be mounted after the collectors in order to get the maximum continuous extraction effect; if they're mounted ahead of the collector, they'll only see one cylinder's exhaust pulse. Unless you have pretty close to a zero-backpressure exhaust system after the collectors, they won't be very effective.

 

[MaineShark]

Hmm... I wonder what would happen if you mounted a nozzle in each of the four tubes?

Probably best to use something else (electric or belt-driven), though, with sidepipes.

Joe

 

[JohnZ]

The system is only effective under wide-open throttle, full load, high rpm, low backpressure conditions; any other time, a properly-configured PCV system will work just fine. This stuff is "race-only", and is worthless on a street-driven car (except for looks).