is it true that the rotary uses up alot of fuel? if so, does an oil catch tank help?

 

Yes, rotaries are relatively ineffecient and run rich.
No, an oil catch can won't do anything useful since the oil doesn't leak, it gets purposefully injected into the engine, burning with the fuel.

Your question seems to be uninformed, where did you get the idea?

 

Seriously, how would an oil catch tank help fuel economy? I've heard some crazy questions before, and this is right up there with my mom trying to rewind the DVD before she returned it to the video store.
Edit: Sorry, I usually try to be nice to newbs, but this questions caught even me off gaurd.

 

lol^ your mom too huh

 

There is no relationship to an oil catch can and the amount of fuel being burned.

Anyone can use an oil catch can. The purpose is to prevent the crankcase blowby oil and moisture from entering your intake or turbo, and to collect it into a tank that you drain occasionally. The is an issue on piston vehicles because of typical improper PCV location. Moisture and oil are the the ingredients of sludge, and there are certain engines that can clog the intakes. Other engines end up oil burners because they can suck motor oil right through the PCV. It is also an issue on turbo engines that vent to the suction side of the turbo. The catch can will help keep that oil, moisture, and sludge from crudding your turbo.

 

My did it as well. I guess it runs in families. I had to explain to her that it worked like a CD player, which kinda worked.