Are catch cans at all necessary on rotaries? I have a streetported 12a with a blow through setup....Advantages and disadvantages, please. The write-ups that I've seen, really only apply to boingers. I'm stealing a "kiwi" term, there. Boingers, refering to, piston engines.

 

Boingers?? never heard that before!!
Yep catchcans are worth it on rotaries. With the factory crankcase piping removed, as many people do, there is still a fair amount of oil vapour that condenses and needs somwhere to go. With a catchcan fitted the vapours condense and accumulate here and with the breather on top letting out steam/pressure, whatever, emilinating the risk of pressurising the crankcase. I emptied mine out a while ago, pretty amazing how much builds up!!

 

Catch cans are fairly easy to construct if you have the proper tools. Fabbing up things yourself is always a nice learning experience I've found.

 

I just installed the greddy unit on my single set up. I ran the top nipple of the oil filler neck to the "clean filtered " air of the turbo. I ran the lower nipple of the fill neck to the can. I have a filter on the other can fitting. I mounted the can to the side of the alternator bracket where the power steering pump was. Hopefully be turning the car over this weekend. ! G

 

Why would you want to burn the oil-water-fuel mixture in your engine and contaminate every system between the turbo and the rotor? That sludge will build up in your intake. Just look inside any factory intake and you will see brown oil film deposits from the emissions system.

Just run a hose from the filler neck to the ground...or you could be fancy and throw drop some of your paycheck on a soda bottle and zip tie it in place. My 16oz soda bottle would need to drained about every 5k miles. It would be 1/4 full of water and 1/4 full of oil.

Just because it's shiny doesn't mean it's better.

 

some of the sponsored drift cars drain into Red Stripe beer bottles. FANCY!

 

Yaaaaa mon hurray beer!

 

What's funny is they dont even empty the bottles. They send them back to redstripe to be carbonated, capped and sold.

You didn't think they had a brewery did you? Redstripe tastes like it might as well be crankcase filth.


Get a catch can. I believe they are a must on any forced induction setup.

 

[oops wrong thread]

 

Oh my god. I dont remember posting that.

My opinion still stands. That **** is disgusting. Redstripe, it's crap. Hooooraaaay crap!

 

I run mine to a bicycle water bottle, and have set the dump line with an internal hose, so it's lower than the outline to primary turbo. I doubt my turbo/intake is really seeing much oil (as it dumps into the can first, the vacuum just helps pull air pressure out of the oil pan.

Similar to Greddy or other catch can, but with less chance of oil suckage to turbo under normal conditions, and way easier to drain. The reason I don't just vent to atmosphere is that atmosphere doesn't "pull" pressure as well, and it's a potential external leak point. The way the aero works on the car, any engine bay oil leak gets pulled directly to the driver's rear tire. Not good.

 

Funny thing is that most people that have catch cans do not have them connected in a way that makes them functional. Then again, most catch cans readily available do not have an effective design.

As far as routing goes, the engine needs to have a source of filtered air on one end and the other end connected to the catch can. The catch can then needs to be connected to a source of vacuum. This way the vacuum sucks dirty crankcase air through the catch can. Without the vacuum, crankcase air flows whichever way it wants to.

On to the design of catch cans. If you've ever disassembled one, more than likely its just the two hoses connecting to the top and nothing inside. An effective design would have a large distance between the inlet and outlet to give time for the vapors to condense inside the catch can. Some sort of baffling, such as stainless steel wool, helps too.

 

Yeah. I've noticed that to. I have an hks catch can with both bungs at the top. It's semi baffled meaning it prevents slosh somewhat but the inlet and outlet are right next to eachother so vapors that dont condense and drop to the bottom still get sucked into the engine. Could be a 50/50 split on that. Half goes into the engine, half settles at the bottom of the can. SOOOOO, when i have time i'm making a dividing wall in mine that goes about halfway to the bottom of the can with wool on the bottom. Should be a good thing!


I refuse to run a filter on mine because i'm n/a. Even after i go turbo i think i'll run a closed loop system that does not vent into the engine bay.

Two ways to do that are to use the exhaust to pull crankcase vapors (yes, you can do that. fyi) or have your vac source between the turbo and the air intake filter.

 

I used a shiny eBay brand coolant overflow bottle. On the side of it there is a hose running up and down to see the coolant level. I cut that and put in a hose barb T between the cut hoses. Connected that other end of the T to a hose with a ONE WAY CHECK valve, then to a boost source. The other nipple on the coolant tank is just connected to the oil filler neck. I would think the ck valve is needed so you're not boosting your crankcase.

Also this helps me burn less oil. My turbo return line is at an awkward spot so this helps to "pull" my return oil coming from the line.

 

Sounds like a nice setup. Any pics?

 

yesss please post some pics of how u routed it... im not comprehending what sources u guys are using for vacuum... i assume the ones on the front of the UIM by the throttle body?

 

FD routing is different than FC, so you need to specify what you have. On the FC there is already a ventilation port on the middle iron as well as a port on the oil fillter tube. On a single turbo FD you may want to tap the rear oil drain blockoff plate as an extra ventilation port in addition to the factory ventilation from the oil filler.

Also, some run open vented and some don't. That affects the routing.

 

I have a 13b-re, should be the same on all 13b's though. There must be a nipple on or near the base of the oil filler neck. I will get some pics in a little bit, it's a pretty ghetto setup though.

 

I have a S4 Turbo II so all i have to run is one line from the bottom of the oil fill tube to the catch tank and vent the tank with a filter?

Correct?

 

I've always just vented with a hose to the ground, never really thought about oil getting on the tires. I guess I'd better get a tank.

 

That's not a good idea because oily roads are dangerous.

 

I blocked all nipples off and drilled a hole in the oil cap put a -8an 90degree pass thru fitting in and sealed it ran a line to and empty bottle and like previously said it needs to be emptied often alot of water and oil accumulate, very simple. I believe I picked this up a while ago from Mr. Hanover...

 

On my FD I use a small Jazz catch can with a filter... one side goes to the oil filler neck and the other goes to the unused turbo oil drain on the rear iron. After 5 track sessions I've accumulated a few drops of oil. Looks like venting both sides of the engine is key...