Installed my BT catch can from Moe's today

[Hemi Joe]

Really? My TB needed a good wipe, and STUNK when I opened the throttle plate. I'm chomping at the bit to get my Moroso installed, knowing the crap the engine is feeding back into itself.

Yeah, it was clean, I was prepared to clean it up, that's why I took it off.

 

[WVUguy]

What exactly is the purpose for a "catch can"? I gather it collects oil but where does it come from and what is the benefit?

 

[Synolimit]

What exactly is the purpose for a "catch can"? I gather it collects oil but where does it come from and what is the benefit?

to catch oil that is blown out the crank vent. your piston rings are not 100% air tight. when combustion happens some burnt up gas/air is "blown by" the piston rings and enters the oil pan, which is why oil turns black over time. the pressure "would" build up till the pan blew up if you didnt have a vent on the block somewhere. the PCV system helps this built up pressure by running a hose from the intake manifold to the PCV which is attached to the crank vent. so under normal throttle or idle the intake manifold is sucking air out of the oil pan/block. during this sucking action some oil comes out with it. without a catch can that oil gets sucking into the intake manifold and gets mixed in with the gas and air. this is bad for horse power since your motor doesnt want gas, air and oil. the blow by oil is also sticky like tar and after time that build up in your hoses, intake manifold, throttle body, etc just gets nasty and it totally preventable. under full throttle though you PCV system closes and no air escapes untill you let off the throttle and go back into a vacuum where the intake sucks again.



i was never a fan of a catch can. Run a clear hose from the side going back to the intake and you will still see a ton of oil! Kind of defeats the purpose to have something when you're still letting oil back in. A air/oil separator is what you want and need! Only way to be 100% sure. I made my own from a copy of someone else's (name left out). Here you get the idea from them...they cost almost $400 yet I only have about $12 in each.



Blow by/oil enters the side port to the left/middle of the AOS in the pic.

It then collects and drains out the bottom. Some cars have a drain back to the oil pan so these are 100% maintance free! Never need dumping.

The "baffle" you can see that oil would have to make its way up into the inner can and then somehow get sucked up into the "hanging in mid air tube", which is impossible. The inner can also has a drain hole to dump whatever makes its way in, plus for condensation that always builds up because its a metal can going through temp changes.

 

[Hemi Joe]

After another 1500 miles.

 

[WhiteExpress]

It then collects and drains out the bottom. Some cars have a drain back to the oil pan so these are 100% maintance free! Never need dumping.

You do not want to circulate this oil back into the oil system.
It gets contaminated with... stuff. Hence the 'dump' feature of the BT unit.

 

[chuck]

You do not want to circulate this oil back into the oil system.
It gets contaminated with... stuff. Hence the 'dump' feature of the BT unit.

I had been wondering about the pros/cons of doing that...or if it was even possible. Thanks for posting up about it.

 

[Synolimit]

You do not want to circulate this oil back into the oil system.
It gets contaminated with... stuff. Hence the 'dump' feature of the BT unit.

Guess ill have to call up every racing team in the world and tell them they're doing it wrong I guess. Specially all subi and Porsche race teams. They'll have to invent an IV oil drip then since by the end of a race the motors will be out of oil.

There is no stuff as you're thinking, its a closed system. Your oil gets stuff in it every second anyway as I said from burnt carbon blowing by the piston rings turning your oil black. Just because the oil leaves the block then comes right back in its not going to hurt anything. Ran my subis 40k till I sold them with zero issues and perfect oil analysis's done every 3k oil change. 99% of cars besides people with AOS's or catch cans have their blow by oil get sucked into the manifold and burnt up in combustion. Then that burnt oil and burnt gas still blow by the rings and mix with the oil anyways. What's it matter if it mixes back as liquid oil or burnt up tar? It's fine if its run back but since these aren't race trucks I don't care to look for a return port. Ill just empty the AOS. Again I have a vast knowledge in this. If you still think I'm wrong call these guys and report back what they tell you.

http://www.crawfordperformance.com/

 

[HLram]

I am by no means arguing, but I can testify to what my old 07 hemi did. The TB had to be cleaned several times over the 75,000 miles I put on it (I bought it used with 80,000 miles) because it would get super nasty and would idle rougher etc. It never ever had to have any oil put in it in between oil changes (Amsoil) I swear it even got worse gas mileage when it was gummed up. But I know for a fact it would get nasty and run rough. Would run smooth after cleaning. My current 12 model TB was a little dirty when I put my Moe's 85 mm TB on it at probably 20,000 ish miles on it. Now, I do idle ALOT. So that may be why mine was dirty and why my old truck was always gumming up. I have read that it also affects the octane of the fuel, too? These trucks are not race trucks - that much is true. Race engines aren't usually built to last 200,000 miles like I want mine to do, and also not built to idle alot and putt thru rush hour traffic, etc. Not built to pull heavy loads. Not built to run across the Arizona desert one day and then go the snowy areas in Montana the next. All of this from a daily driver. These are not race vehicles, so they have to last. That is why I run a catch can. Because for a minimum amount of money I can have something that may or may not help my engine last longer and burn air/fuel more efficiently because Sean at Hemifever said so in a post a few months ago. These are good enough reasons to run one. Sorry for the long post. Again, I am NOT arguing. LOL.