I havent read info saying a chambered muffler system cant be used. In fact most of the old school v-8 guys were the originators for testing exhaust back pressure to properly design a system so that you could.

you right that our mufflers do make it easier due to the fact that we use a straight through design.

If your looking for a evac setup where you use vacuum from the exhaust there are a lot of designs on the internet. Its a very old concept just most people either dont trust it, arent aware of it, or dont want to go through the hassel of it. Its easy to plumb it into your intake!

http://www.sdparts.com/product/MOR25900/MorosoCrankcaseEvacuationSystem.aspx

Thats the type of setup your looking at, now granted you dont need all that equipment since we dont have a v-8. If you read more about it, you need to be careful (mostly when using vac pumps) because too much vacuum is more harmful than good.


Personally i would measure the vacuum created at different rpm and load points. Place a dimple into the pipe right upstream from the point you want to tap into to create a venturi effect. Measure your vacuum and note it. Next thing is you will need to build a catch can setup and install it in the conventional manner except the vac source will be the exhaust. You will need check valves so that the exhaust doesnt push back into the catch can. After that your going to need to tap into the motor in some way to monitor crankcase pressure to see how well you evac system is working. There is no basic design that works on all 4 cylinders or all motors. Each system needs tobe taylored to each setup.