[dreksnot]

To expand on what my issues was and most certainly sounds similar to yours, but mine's a lengthy story.

Since I was pushing x,xxx hp, I needed more crankcase venting. So, I went bigger, and dual MM catch cans (cc) (-12AN and -10AN tubing). The "larger" one was a vented setup PCV off the passenger side valve cover off the oil-fill cap location, check-valve line behind the throttle body on the intake, while the "smaller" was venting on the driver's side valve cover rear OEM location.

OEM valve covers: First indication of trouble. Autocrossing and the hard turns and braking. Right after a hard (boosted) acceleration and releasing the throttle, positive crankcase pressure would vent into the cans AND the check-valve would go from closed to open allowing the unmetered air from the PS cc to pull air from that can/vent into the intake. But, since the oil-fill location was on the front of the valve cover, guess what oil in the valve covers does while turning hard and braking? A combination of the crankcase venting behind the oil and the vacuum from the intake pulled oil into the can, filling it quickly and thus sucking into the motor to make for the nice smoke screen at autocross, and misting the engine bay, windshield and the whole rear of the back bumper. Nasty cleanup, nonetheless. (a thought was to weld bungs in the middle-top of the OEM valve covers where oil doesn't get slammed (front or back))

So, attempt Number Two was to swap out the OEM valve covers because I thought I needed way move venting capacity. So, here goes with BTR "baffled" valve covers on. Those had hefty -12AN fittings on the front and rear of the valve covers. So, I thought trying the rear location on the PS might just work since the front on the OEM's didn't. Heck, I would have to accelerate mighty hard and the oil would have to run a longer distance from the rear valve cover against the forces of acceleration, right? So, I was at the TX Mile for this sortie. Let me say the BTR baffles were a joke. I filled up the cc's midway through the run, misting the windshield, oil-washing the whole rear of the bumper, engine bay looked like a spattered mess. (BTW, oil injection is a frowned upon octane reduction method)

I contacted Dave at MM seeking input but nothing really came about. Also, my engine builder suggested a puke can. I didn't want a band-aid.

Attempt Number Three. I searched and searched and found Motion Raceworks baffled valve covers. The baffling looked OEM-like but much more venting capacity. Calls to them only yielded a pitch of how well they would work for me with the x,xxx hp and required venting. So, WTH and let's give it a try. The VERDICT was they were head and shoulders better with their method of baffling and along with my setup reduced oil "transfer" remarkably, like getting 2-4 ounces in the PCV can on PS (almost nothing in the draft can on DS) versus overflowing the PCV side after a race day or a few months of daily. So, Motion Racework valve covers provided a HUGE improvement!

One more thing I did (and perhaps the only thing I would have needed to do in the first place) was to insert a manual ball-valve between the PCV check-valve and the cc. This, I thought, I could shut during extreme driving so my cc setups would be draft (no PCV to be able to pull oil into the intake). I never got around to trying it but I thought in principle, it would work. Keep the valve open for daily driving and less cockpit smell, close for racing. Hell, this $15 item and 1-minute installation could have been the simple fix the whole time..... and the more I think about it, the less I want to think about it