If you do not use a catch can you should be using
FULL SYNTHETIC MOTOR OIL
It will not sludge/gum up inside of the motor as fast or as much. But not completely
Putting on a catch can is still the very best to keep your engine's innards clean. If you go to the Mini Cooper Forums you can read about a lot of Mini's that had serious problems with gumming up the engine due to the design of the Mini Turbo engines.
Putting cleaners in the gas tank will not solve the problem at all. They do clean the injectors and top of pistons,etc but they do not stop the oil mist that causes all of the problems. Only a catch can will solve the problem completely.
In the good old days they just stuck a tube as a vent and pointed it to the ground. Any oil mist just went out that tube and polluted the earth. All new engines have a closed system and allows the mist to hopefully be burned along with the fuel. Of course that still allows some sludge buildup.
The big reason that "all" car company's do not use catch cans is because they know most of the oil caught in the cans would end up down drains or in landfills. They all got together and use a world standard of the PCV valve but did find another better system in the last few years.
Read this> http://autos.yahoo.com/maintain/repa...ques079_1.html
2012-candy red- V-6 MCA, Automatic Trans. CFM Valve cover breather. MMD blackTail light trim.Magnaflow axle back street mufflers, JLT oil catch can.MMD hood struts.
Airaid Cold Air intake. red caliper covers, 3.7L performance engine cover, Flat black hood spears.Boss 302 strut brace, CDC rear panel, Trunk Cargo net,--Dash carpet cover,
Viser stickers to cover ugly yellow warning crap,Aluminum driveshafft and Swarr Bar.