Crankcase Vacuum from exhaust?

ratpick63

detroit iron defector
May 4, 2006
62
0
0
Glendale, CA
Ok this is may be a little out there, but I'm having trouble finding anything about this-
I remember seeing a cheap little kit in Jegs or somewhere for a little tube to weld into your header(s) that would be connected to the crankcase. The exhaust gas flowing by supposed to create vacuum effect on tube and thus vacuum in engine/ crankcase area. Sounds like it'd work. But is this only a drag race kind of thing? I mean, would it only be effective at WOT? Possibly pushing exhaust into engine at part throttle or decelleration?

I can't find anything about this online. I don't even know what this setup is called. I know it'd be all kinds of emissions illegal (I'm in Cali) but I'm thinking it may be good for my Yamaha-chopper. It's old and wouldn't matter if I suck oil vapor straight into exhaust! Help me out.