Pour it out? Really?

[THETANK]

how come highway dry and city collects oil?????????

 

[DannyMK2]

Forget the idea of "dumping it back in". Consider a different designed catch can where the gathered oil is drained back to the engine crankcase immediately and is assimilated back into the rest of the engine oil immediately. Any moisture is evaporated.

sure, that would be a more ideal set up then having to empty the can on a regular basis. as someone already stated, the hellcats have adopted sort of a built in catch can in the valve cover. i think they call it an air/oil separator. from what ive read many guys feel its not as effective as it should be and they install a conventional catch can as well. if the idea could be perfected on that would be the most efficient way to go. as far as what we currently have available (for the ram at least), your probably better off not re-using it (but if you really wanted to you probably could).

 

[MANual_puller]

When I had a catch can on my 14 it would collect when driving in the city but when on the highway (4000+ miles) it was bone dry, what's the reason??????

how come highway dry and city collects oil?????????

On the highway the truck is using more power, thereby the throttle body is open farther. RPMs are similar between city driving and highway driving and because the throttle body is letting the engine have more air the manifold has lower vacuum and doesn't suck as much stuff out through the pcv. That's the science behind it.

 

[MANual_puller]

sure, that would be a more ideal set up then having to empty the can on a regular basis. as someone already stated, the hellcats have adopted sort of a built in catch can in the valve cover. i think they call it an air/oil separator. from what ive read many guys feel its not as effective as it should be and they install a conventional catch can as well. if the idea could be perfected on that would be the most efficient way to go. as far as what we currently have available (for the ram at least), your probably better off not re-using it (but if you really wanted to you probably could).

boosted applications will have higher flow out the pcv since more gasses are getting past the rings due to higher pressures. The engineers had to do something but likely compromised short of perfection as is often the case.

 

[kris72079]

boosted applications will have higher flow out the pcv since more gasses are getting past the rings due to higher pressures. The engineers had to do something but likely compromised short of perfection as is often the case.

Higher crankcase pressures in a boosted application are also partially due to the fact that a ring gap measurement in a boosted/N2O motor are wider to compensate for higher combustion chamber temps and therefore greater ring expansion. So, during lower cylinder pressure situations the ring gap and associated blowby is increased. Also the PCV flow is more regulated by intake manifold pressure than by crankcase pressure. That's why hurt motors can experience dipstick pushout and develop gasket leaks with a properly functioning PCV system.

 

[MANual_puller]

Higher crankcase pressures in a boosted application are also partially due to the fact that a ring gap measurement in a boosted/N2O motor are wider to compensate for higher combustion chamber temps and therefore greater ring expansion. So, during lower cylinder pressure situations the ring gap and associated blowby is increased. Also the PCV flow is more regulated by intake manifold pressure than by crankcase pressure. That's why hurt motors can experience dipstick pushout and develop gasket leaks with a properly functioning PCV system.

Right, I was trying to keep it a fairly simple explanation. You'll get more blowby until warm no matter what the application. The question was city vs highway driving. I was answering the question assuming that the engine was warm and the ring gap had closed as far as it was going to. There's clearly more than one variable at play. I actually answered only to pacify the curiosity more than anything repeat questions, especially when it's been covered in a few other threads, kinda bug me but I wasn't going to be rude about it. Some people are just as fluent with the search tool as they are with the fluid dynamics in an internal combustion engine

 

[kris72079]

...repeat questions, especially when it's been covered in a few other threads, kinda bug me but I wasn't going to be rude about it. Some people are just as fluent with the search tool as they are with the fluid dynamics in an internal combustion engine...

speaking of repeat questions covered in other threads, I've come across other posts in other threads about catchcans that suggest (some from sponsors) that there is a HP gain to be had by installing a catchcan. This makes me scratch my head and bite my tongue at the same time. The only feasible explanation that I could even imagine for this being a true statement at all is the argument for developing carbon deposits over time above the intake valve from the oil or possibly contaminating the intake charge. Either way, EGR is a significantly more detrimental system from these standpoints. Not to hijack the OPs thread

 

[MANual_puller]

speaking of repeat questions covered in other threads, I've come across other posts in other threads about catchcans that suggest (some from sponsors) that there is a HP gain to be had by installing a catchcan. This makes me scratch my head and bite my tongue at the same time. The only feasible explanation that I could even imagine for this being a true statement at all is the argument for developing carbon deposits over time above the intake valve from the oil or possibly contaminating the intake charge. Either way, EGR is a significantly more detrimental system from these standpoints. Not to hijack the OPs thread

And this is why I like the 2500/3500 truck version of the 5.7 hemi. My '11 had no egr or mds from day one.

 

[Dubstep Shep]

speaking of repeat questions covered in other threads, I've come across other posts in other threads about catchcans that suggest (some from sponsors) that there is a HP gain to be had by installing a catchcan. This makes me scratch my head and bite my tongue at the same time. The only feasible explanation that I could even imagine for this being a true statement at all is the argument for developing carbon deposits over time above the intake valve from the oil or possibly contaminating the intake charge. Either way, EGR is a significantly more detrimental system from these standpoints. Not to hijack the OPs thread

Oil in the intake air will reduce the effective octane of the fuel.

If you have a custom tune, less octane means less power.

 

[kris72079]

Oil in the intake air will reduce the effective octane of the fuel.

If you have a custom tune, less octane means less power.

I fully understand the concept, but I challenge anyone to prove a measurable difference between using a catch can setup vs not.

 

[Hemi450hp]

I fully understand the concept, but I challenge anyone to prove a measurable difference between using a catch can setup vs not.

The catch can itself does not give you more power. Having a catch can installed keeps oil out of your fuel which helps prevent spark knock. Having the catch can installed allows your tuner to get more aggressive with the tuning without having to worry about knock, so that is where the increased power comes from. It is not much, but every bit helps. If you can keep your motor clean while also squeezing out a few extra hp, then why not?

 

[kris72079]

The catch can itself does not give you more power. Having a catch can installed keeps oil out of your fuel which helps prevent spark knock. Having the catch can installed allows your tuner to get more aggressive with the tuning without having to worry about knock, so that is where the increased power comes from. It is not much, but every bit helps. If you can keep your motor clean while also squeezing out a few extra hp, then why not?

Agreed. The theory is strong for being able to add timing to the tune with a cleaner AF mixture. However, I'm comfortable in saying that without a built motor stock SCR much less DCR is low enough to not see any direct effect from a catch can alone. The thought of keeping the oil vapor out of the intake manifold and intake runners is good but EGR has a much more negative impact than a healthy motors PCV system. I'd hate for anyone to think that I'm trying to argue the point because that is certainly not my intent. But the OP spoke of the economics of reclaiming the oil from the catch can vs discarding it. Given that debate, it is significantly more economical to go without a catch can setup than to debate the reclamation of the oil. In stock trim you'd more benefit from a good dyno or preferably driving tune with a good flowing intake and exhaust over anything else. If you wanted to start making investments. Just my $0.02.

 

[Rupert]

I empty my catch can when I change my oil so I'm not saving it or dumping it into my sump.
Even if I do empty the catch can ( Ill be checking the one I installed recently but don't expect much oil to be in it. ) in between oil changes the 2 OZ wont even show on the dipstick so its kind of a moot point.
Unless you have an older engine that has a lot more oil blowing by in which case you have bigger issues coming than the expense of a few ounces of oil.

 

[R.L.K.]

what about the older cars that vented to the atmosphere? should we slap catch cans on them so we can collect and dump that back into the crank case?

That's funny right there now , I don't care who you are !
Good one Sir !