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Discussion Starter #1
Newbie here, I see a lot of you folks add a catch can to your rides: question is why? I understand that it collect oil from blow by(?), then what happens? Do you dump the oil, add it back? or is it just a good thing to do? thanks
 

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This topic has been discussed many times on this forum.

Basically, the air that comes through your intake system and goes into the combustion chamber won't just be air. It will contain some oil particles which can, eventually, build up in your intake (see photos, below). This can cause:

Knocking
Pre-ignition
Loss in power
Loss in fuel economy

An oil catch does a good job of catching or preventing the oil from re-entering the intake tract. A catch can is placed right after the PCV and before the intercooler, if so equipped (see photo, below of my catch can). This means that a more pure (sometimes 100% pure) air mixture will go through the intercooler and intake valves. A more pure air mixture entering the intake valves means no caking and none of the symptoms listed above.

An oil catch can doesn't add any power or make any cool noises, so it is often overlooked when modifying vehicles. What is does, however, is prevent a loss of power, as miles pile up, due to your PCM retarding the timing to prevent pre-ignition. Simply stated, a catch can will ensure you are always running the most power possible by having a cleaner intake tract free of oil.

Also, you should never pour the blow-by back into the engine. It is a nasty brew of oil, water, gasoline and acids.
 

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My question is, if they are so beneficial, why are they not standard equipment? It would not be an expensive piece for the engineers to add. With all the different engine manufactures out there, not one thought it was a good enough idea? It's my understanding that they considered them and decided against them. I'm just not sure why.
 

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My question is, if they are so beneficial, why are they not standard equipment? It would not be an expensive piece for the engineers to add. With all the different engine manufactures out there, not one thought it was a good enough idea? It's my understanding that they considered them and decided against them. I'm just not sure why.
Catch cans need to be emptied periodically, if they are not maintained they become a detriment rather than an enhancement. Manufacturers may not want the liability associated with owner neglect. As well, many vehicles perform well throughout their lifetime without a catch can and the need for them is constantly debated.

When I removed the intake manifold from My Scat Pack I noticed a significant accumulation of oily condensate in the manifold and head even though a catch can was installed. I'm sure the accumulation would have been worse if a catch can had not been installed. In my opinion the oily condensate doesn't serve any useful purpose in the intake system. If a catch can can remove a portion of the oily condensate being introduced into the intake system that's a good thing.

My Ram has 150k miles without a catch can and runs fine but for the price of a catch can it's worth keeping some of that crap out of the intake system. If I get a new Ram it will get a catch can as soon as it gets home.
 
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My question is, if they are so beneficial, why are they not standard equipment? It would not be an expensive piece for the engineers to add. With all the different engine manufactures out there, not one thought it was a good enough idea? It's my understanding that they considered them and decided against them. I'm just not sure why.
Hellcat has a special system that reduces the need for a catch can but the only way the OEMs would add one is if it drained automatically into the pan and guess they don't feel it's enough of an issue to go thru with the extra complexity and expense.


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Discussion Starter #6
I have a 5.7 2014 model, with no intercooler, would this be beneficial? Only 13K. How about using cleaners to remove carbon build up?
 

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My question is, if they are so beneficial, why are they not standard equipment? It would not be an expensive piece for the engineers to add. With all the different engine manufactures out there, not one thought it was a good enough idea? It's my understanding that they considered them and decided against them. I'm just not sure why.
Multiply $150 times the thousands of Challenger & Chargers built. It's all about bean counting.
 

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My question is, if they are so beneficial, why are they not standard equipment? It would not be an expensive piece for the engineers to add. With all the different engine manufactures out there, not one thought it was a good enough idea? It's my understanding that they considered them and decided against them. I'm just not sure why.

Rob466 replied and did a good job but I'll add some comments.


The catch can collects (some not all) combustion blow by compounds. Water, oil, unburned fuel. At some point this collection of fluid represents a hazard to the engine for if the stuff is allowed to accumulate too long the can contains a good amount of fluid. Under some combination of events this fluid can be ingested by the engine and puts the engine at risk of (at least) one cylinder suffering from hydraulic fluid lock which can ruin the engine.


Emptying the can on an oil change schedule may not be often enough in all cases.



There is too always the concern about the environment. There is a well defined procedure for dealing with the oil and filter when the car is serviced at the dealer or by an indy repair shop.



For the owner though say at the gas station if the requirement was to say empty the catch can every fill up (or every 1000/2000/? miles) there is no place to dump the contents. At home the owner would have to empty the catch can contents into some other storage container and then when he changed the engine oil at that time I guess dump the contents of this storage container in with the engine oil and lug the engine oil to the recycling center.


It is quite common for owners to not even bother checking the oil level frequently. How many would ignore/not bother emptying a catch can regularly? At least with engine oil there is an oil pressure warning light, a low oil level warning (maybe). The catch can could require expensive sensor fitted to warn or remind the owner the catch can needs attention.



Yet another concern -- this with a catch can added not by the factory but by the owner -- is if the car is sold/traded in, the info regarding the presence of the catch can may not be passed on to the new owner. The new owner may be unaware of its presence and its need to be periodically emptied. If this is not done the can fill up with fluid and at some point a good slug of this fluid will be ingested by the engine with almost certainly disastrous results. If this happened some time after the transaction there may be no repercussions to the previous owner/seller. But if this happened "shortly" after the transaction...



Last but not least if Dodge fitted a catch can at the factory all other automakers would have a field day pointing out how Dodge engines were so bad they needed a catch can fitted to catch stuff that our engines don't emit. That the catch can increases the complexity of the servicing of the car and requires more frequent servicing to ensure the catch can doesn't get dangerously full would also be noted.
 

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Thanks for all your replies, even tho I'm not the OP lol.
The environmental issues actually make the most sense to me, even more so than the cost or maintenance. I'm surprised California hasn't banned catch cans yet. You know the majority of people don't dispose of the contents properly.
 

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Thanks for all your replies, even tho I'm not the OP lol.
The environmental issues actually make the most sense to me, even more so than the cost or maintenance. I'm surprised California hasn't banned catch cans yet. You know the majority of people don't dispose of the contents properly.
Until the mid-60s, the blow-by was just vented into the atmosphere. When that practice ran afoul of environmental laws, it was decided to burn it in the engine, just like cities used to burn their trash in incinerators.
 

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Catch cans need to be emptied periodically, if they are not maintained they become a detriment rather than an enhancement. Manufacturers may not want the liability associated with owner neglect. As well, many vehicles perform well throughout their lifetime without a catch can and the need for them is constantly debated.

When I removed the intake manifold from My Scat Pack I noticed a significant accumulation of oily condensate in the manifold and head even though a catch can was installed. I'm sure the accumulation would have been worse if a catch can had not been installed. In my opinion the oily condensate doesn't serve any useful purpose in the intake system. If a catch can can remove a portion of the oily condensate being introduced into the intake system that's a good thing.

My Ram has 150k miles without a catch can and runs fine but for the price of a catch can it's worth keeping some of that crap out of the intake system. If I get a new Ram it will get a catch can as soon as it gets home.
When you figure out how to install a catch can on a Ram, please let me know how you did it. Right now my MO is to clean the throttle body with brake cleaner, which always results in an improvement in performance.
 

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When you figure out how to install a catch can on a Ram, please let me know how you did it. Right now my MO is to clean the throttle body with brake cleaner, which always results in an improvement in performance.
Admittedly, I have not installed a catch can on a Ram but if I were to do so I would probably follow the instructions provided by Billet Technology or other suppliers. Looks to be similar to installation on a 392 other than the bracket location.

I had not thought of using brake cleaner to clean a throttle body, I normally use throttle body cleaner. Is there some advantage of using brake cleaner on a throttle body?
 

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Thanks for all your replies, even tho I'm not the OP lol.
The environmental issues actually make the most sense to me, even more so than the cost or maintenance. I'm surprised California hasn't banned catch cans yet. You know the majority of people don't dispose of the contents properly.
Think of the CC and its contents as just another part of the engine's oiling system. When you change the engine oil, the used oil that is drained out of the sump has to be properly disposed of according to a myriad of state and federal laws. The CC's squeezings are no different. Just pour them into the same used oil container that catches the oil from an oil change and be done with it.

Until the mid-60s, the blow-by was just vented into the atmosphere. When that practice ran afoul of environmental laws, it was decided to burn it in the engine, just like cities used to burn their trash in incinerators.
I can clearly remember using the little breather elements on the valve covers of the SBCs I worked on and built while in high school, and that was much later than the 60s. Are you telling me I was being a lawless hooligan back when I was younger??? (Wouldn't bother me, I honestly was fairly law-averse at the time, adding on another broken law won't change anything now.)


When you figure out how to install a catch can on a Ram, please let me know how you did it. Right now my MO is to clean the throttle body with brake cleaner, which always results in an improvement in performance.
Why is the RAM different from the LXs? Surely it has unused bolt holes on the intake/water pump/etc. Get creative! I've managed to come up with a workable mounting bracket from scratch for mine, I know you can on yours too!

In the immortal words of my high school guidance counselor, "You're so capable!"


A lot of great information on this thread.

Here is a photo of what my catch can collected on my 392

...

- Alexis
Do you know how much is there? I've been able to average mine out to right at 1 oz per OCI (usually about 4-5K miles). I'm curious how that compares to others' average collection per OCI.
 

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Here's something that nobody seems to acknowledge, and also never seem to have a good rebuttal for.

Why would you run a catch can if the majority of challengers sold are not enthusiast owned and have no idea what a catch can is, but never seem to have ill effects of not having one?

AND...

Why would Dodge not put one on from the factory if its so crucial? If it was an epidemic, you'd better believe there would be a TSB or recall if engines were in danger of failing over lite oil consumption.

Did anyone ever think that the condition that catch cans "fix" might have been planned for by the engine designers and engineers?? I'm sure factory calibrations are set with lite oil consumption in mind at some level. Then you go modifying what was put in place? I think its not going to hurt to have one, but its completely pointless. Its a placebo. Sure you get a small can with oil that was captured, and you pat your self on the back. But again, its a nonissue in the long run and I would be shocked to ever hear about an engine that died because it did not have a catch can...
 

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Not "nobody", but definitely the same people that feel a strut tower bar's effects.

:4:

FWIW, I run both a catch-can and STBs. Neither does anything of great value, but both look good.
The typical CC will have a real (positive) effect on an engine that has an intake of the dual-runner design type. The 5.7L is not such an engine, but the old 3.5L was and the new 6.4L is as well.

If an engine with a dual-runner intake is run long enough without any sort of CC-like device, the inside of the intake is prone to getting gunked up enough so as to interfere with the operation of the Short Runner Valves. A P1004 DTC on the old 3.5L engines was a surefire indication the inside of the intake plenum was now so gunky it couldn't smoothly operate the valves that separate the long runners from the short. I don't know the equivalent DTC on the 6.4L engine, but it has one I am sure.

Whether or not the 6.4L intakes are as prone to collecting the oil droplets and allowing them to turn to goo over time as the 3.5Ls were (~100K miles was usually it for the 3.5Ls) I cannot say. But the possibility certainly exists just by virtue of the design of the intake manifold.
 

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That's the thing, there have even been intakes showing the gunk on 6.4L engines; no DTCs, and no performance hit.

I get the concept, I really do, but we're solving for "maybe" with a CC.
 
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