I cannot comment on this assembly's performance compared to larger, more expensive options. I collect less than 1/2 cup of oil per year (4000 miles). My gut tells me these are not really needed, but they surely do no harm.
Howard
You've nailed it. There has been many a heated discussion on the benefit of these in other forums. Rarely are they needed. The cases would be when the car is subject to long term high RPM WOT conditions. Not for street driving. Even a 1/2 cup measured over the hours of operation results in only a few drops of oil entering the air intake system at a time. It's not like it's running in there (if it is doing more than that you have aBIG problem and should FIX IT instead of collecting it in a cup). Statements that "you're losing 10s of horsepower without this" are unfounded.
By the way, your observation is consistent with my Shelby GT/SC mustang. The Kenne Bell kit that SAI installed came with the oil separator. In nearly 8000 miles of normal driving and a few offical drag runs, and some "spirited" driving (but no serious track time) I think I had collected maybe 3-4 ounces. (It was clear jar type.)
When I pulled my supercharger on the GT to get the bearings repaired I also saw a little oil around the gasket, but none on the intercooler. That was at about 1500 miles.
Second, you only need it on one side (assuming you need it at all). The side where the PCV valve goes TO the supercharger intake (I think that is drivers side on our cars). If you have oil on that side you've got a bigger problem.
Both of these were explained in the forum, but I can't think of the search that might bring it up.
Maybe the oil collectors with clear jars provide information that is not available other ways, but you're generally right in that they don't do harm. They're kind of like copper bracelets.
