What about an oil catch can? (oil separator)

[exmowner]

After 4000 supercharged kms my air filter looked like it needed a clean/re-oil.

Taking J2m's advice I decided to buy a spare filter to have on hand and went ahead and replaced it.

I also added a K&N pre charger (RE-0810PK Filter Wraps)

This should help keep some dirt and blow by water from getting onto the filter!

Anyways while I had the liner off i decided to inspect the car to make sure nothing looked out of place. I swiped the inside of the supercharger inlet tube with a rag and to my surprise it was coated with engine oil....

This got me thinking and I realized that with the added crank pressure, oil was actually getting syphoned out of the engine threw the PCV valve and getting into the supercharger inlet pipe.

I'm not exactly happy about this extra oil finding its was into the engine. Ive read that oil sucked in threw the intake (blow by) actually reduces octane.

After some searching I came up with an oil catch can or oil separator to help keep oil off my intercooler and out of my intake.

radiumauto(dote)com sell a kit for an e46 m3 but it looks like it would also work great for the e92 m3.

I'll contact them in the morning and if it checks out i'll report back with my findings. I think it's something supercharged m owners should invest in.

Alex

[WarrantyTracker]

The problem you have is common (more with turbos than SCs because turbos are more common than SCs) and a catch-can is the generally-accepted solution. You do NOT want oil vapor making its way back into your intake; that stuff is nasty and will get things dirty, and decrease octane as you mention.

Also, if you blow your engine at the track, the catch can will catch the oil instead of dumping it all over the track. So the car behind you won't crash, and the driver will be appreciative.

Just make sure you set it up so you have easy access to the drain valve.

[Roundown]

Burger (BMS) makes one for the N55/54 that seems to work well.