I have a Bob's catch can too. I really like it.My car seems to collect a lot of oil in my can. I HAD a JLT and it was still letting oil by which was causing it to get in the intake. It caused the octane to drop and it would cause knock. My car would pull as much as 8 degrees of timing due to this. I picked up the Bob's catch can which is really nice and my problem is solved.