Catch Cans, and Is there evidence???

lightNfast · Mar 21, 2017

I've been looking into catch cans and I'm wondering are they really needed or is it that we are just... paranoid? I'm always down to spend money on peace of mind, but I'm in search of facts.

So I pose the question, why are catch cans needed on our motors? Does the crankcase not have proper ventilation, does blowby/oil spray really effect our air/fuel mixture, etc? Seems like every time it is brought up on the forum a picture of gunk is posted, but that doesn't necessarily mean that it is causing harm to your motor. Your essentially interrupting the pvc system of sorting (i.e. oil spray and moisture) out and forcing it to mix in a can so of course, you find gunk. Am I off-base here?

I'm not anti-catch cans at all (in fact I may do it regardless of the responses), but I want to better understand our motor.

DontoMelbo · Mar 21, 2017

Just take a look at some of the pix if you search "walnut blasting di engines". A lot of that buildup can be prevented with a CC. I sure don't want that after xx,xxx miles if it can be prevented.
Here's a good link, even mentions Ford EB engines. http://blog.modbargains.com/get-nuts-feed-bmw-n55-walnuts-get-clean-tune/

AlyourPal · Mar 21, 2017

You're not interrupting the pcv system, just putting a knockout drum where there was previously a straight pipe. It's easy to tell that it's helping your engine: check the catch can after some miles. All of the dirty oil in the can would have normally been thrown straight into your intake. It then gets all over your throttle body, intake manifold, ports, and I would think your valvetrain as well.

I send samples from my oil changes to blackstone for analysis. I don't have another mustang for control obviously, but i can tell you the engine is wearing very well and all systems are green. Even if it's only a small benefit, there is no detriment to using one other than the $100 or so that the catch can costs.

hiccup · Mar 21, 2017

Its all about intake port lubrication vs. a cleaner intake system..Which ever is your preference.

ForYourOwnGood · Mar 21, 2017

Its pretty simple, if you want this crap in your engine then don't use one

just be ready to have your intake valves walnut blasted sooner rather than later. We don't have fuel being injected in the runner like a port injection motor so they never get cleaned.

tw557 · Mar 22, 2017

The thought I have with the picture above is it looks like over half of whats if the bottle is water mixed up in the oil . So I'm thinking all the water condensation would not harm anything. I guess a GOOD system with a large can with multiple baffles certainly can't hurt and would prolong the valve build up. With most systems they are using such small cans. I figure it will be pretty bad if the can gets full and spits a bunch into the intake. Also if running high RPMs a lot might need it more. For daily driving my car uses no oil in 5000 miles. Maybe a couple ounces. I read an article a bit ago about the best catch cans and they are pretty expensive and they went on to show these small can systems still let a lot oil thru. Now I'm intrigued again and need to do some research again.
But I have to say I really can't believe that the oil mist is affecting the fuel mixture and creating pre ignition like some theories have suggested.

Ebm · Mar 22, 2017

Found a post out on the Internet that I strongly agree with. It's worth a read.

The reality check problem I’ve always had with catch cans is that as far as I know, not a single car maker in the whole world uses them, not even the ultra high performance and price guys like Ferrari. They aren’t even used on diesels, all of which are direct injection, which kind of knocks out the C7 DI worry. So do I go with the unanimous vote of all the powertrain design engineers of all the world’s car makers, or the postings of some internet engineers and catch can salesmen. Hmmmm. Doesn’t seem like a tough choice. Yes, they catch a bit of oil, but the “nobody uses them” evidence strongly suggests that essentially the oil they catch would have blown past the valves and burned harmlessly in the cylinders, as indicated in the lengthy post by the GM guy. Remember, oil has a higher concentration of detergent than gas, so it’s not as though going to DI in the C7 eliminates all cleaning capability. And the comment about no catch cans because of the EPA??? Huh??? Cleaner engines give lower emissions, so if catch cans really meant cleaner engines, EPA would not only allow them, they’d require them. Having said all that, if you're a catch can fan and using them makes you feel better, fine, go for it. As several have said, they can't hurt anything. I'm not trying to throw rocks at anyone. I'm simply saying catch cans don't meet my own personal reality check criteria.

HISSMAN · Mar 22, 2017

Most of what builds up on the valves of a DI engine is not oil. I would wager that less than 5% of the buildup is oil. It is mostly carbon from burned and unburned fuel in the combustion chamber that gets deposited on the valves during the normal cycling of the engine. A port injected vehicle has fuel spraying directly on the valves, so it keeps them relatively clean. Yes, oil vapors will lower octane, but at the amount of oil per cycle that the engine sees that is getting blown into the system, unless you have a mechanical defect, will not amount to any octane degradation.

ForYourOwnGood · Mar 22, 2017

Ebm said:
Found a post out on the Internet that I strongly agree with. It's worth a read.

The reality check problem I’ve always had with catch cans is that as far as I know, not a single car maker in the whole world uses them, not even the ultra high performance and price guys like Ferrari. They aren’t even used on diesels, all of which are direct injection, which kind of knocks out the C7 DI worry. So do I go with the unanimous vote of all the powertrain design engineers of all the world’s car makers, or the postings of some internet engineers and catch can salesmen. Hmmmm. Doesn’t seem like a tough choice. Yes, they catch a bit of oil, but the “nobody uses them” evidence strongly suggests that essentially the oil they catch would have blown past the valves and burned harmlessly in the cylinders, as indicated in the lengthy post by the GM guy. Remember, oil has a higher concentration of detergent than gas, so it’s not as though going to DI in the C7 eliminates all cleaning capability. And the comment about no catch cans because of the EPA??? Huh??? Cleaner engines give lower emissions, so if catch cans really meant cleaner engines, EPA would not only allow them, they’d require them. Having said all that, if you're a catch can fan and using them makes you feel better, fine, go for it. As several have said, they can't hurt anything. I'm not trying to throw rocks at anyone. I'm simply saying catch cans don't meet my own personal reality check criteria.

Most manufacturers don't use them because people won't empty them, simple as that. If it fills up you have a big problem. They try to design a PCV system that performs a similar function while letting the results drain back into the oil.

There are huge articles written about the how and why for catch cans along with all the testing evidence you could need. I'm surprised you managed a specific enough search that you didn't accidentally find some. If you don't want to use one, don't. I consider it a small investment to the longevity of my motor.

jacknifetoaswan · Mar 22, 2017

ForYourOwnGood said:
Most manufacturers don't use them because people won't empty them, simple as that. If it fills up you have a big problem. They try to design a PCV system that performs a similar function while letting the results drain back into the oil.

There are huge articles written about the how and why for catch cans along with all the testing evidence you could need. I'm surprised you managed a specific enough search that you didn't accidentally find some. If you don't want to use one, don't. I consider it a small investment to the longevity of my motor.

Exactly. Why invest another $25 into the design of a vehicle when people will ignore them and they'll later become a maintenance and warranty headache when they fill up, and dump larger amounts of oil into the intake.

Personally, it's good peace of mind. My Coyote dumps about 3 ounces of oil residue in my Bob's oil separator during the course of an oil cycle - 10,000 miles. That doesn't sound like much, but it's enough to eventually gunk up the moving parts of the intake. I didn't have an oil separator on my S197 3-valve, and I had to remove and clean the throttle body at 40k miles and again at 60k, and that was with regular 10,000 mile change intervals using Mobil 1. I'll never own a Ford vehicle again, and not install an oil separator.

JR

Teezlr · Mar 22, 2017

Ebm said:
Found a post out on the Internet that I strongly agree with. It's worth a read.

The reality check problem I’ve always had with catch cans is that as far as I know, not a single car maker in the whole world uses them, not even the ultra high performance and price guys like Ferrari. They aren’t even used on diesels, all of which are direct injection, which kind of knocks out the C7 DI worry. So do I go with the unanimous vote of all the powertrain design engineers of all the world’s car makers, or the postings of some internet engineers and catch can salesmen. Hmmmm. Doesn’t seem like a tough choice. Yes, they catch a bit of oil, but the “nobody uses them” evidence strongly suggests that essentially the oil they catch would have blown past the valves and burned harmlessly in the cylinders, as indicated in the lengthy post by the GM guy. Remember, oil has a higher concentration of detergent than gas, so it’s not as though going to DI in the C7 eliminates all cleaning capability. And the comment about no catch cans because of the EPA??? Huh??? Cleaner engines give lower emissions, so if catch cans really meant cleaner engines, EPA would not only allow them, they’d require them. Having said all that, if you're a catch can fan and using them makes you feel better, fine, go for it. As several have said, they can't hurt anything. I'm not trying to throw rocks at anyone. I'm simply saying catch cans don't meet my own personal reality check criteria.

Yep

HISSMAN · Mar 22, 2017

FWIW, I had a $400 catch can system on my DI 135i Twin Turbo. My valves still got caked. Just adding to my earlier post. Oil vapor isn't an issue at the levels that it is introduced to the PCV system.

Ebm · Mar 22, 2017

.

ForYourOwnGood said:
Most manufacturers don't use them because people won't empty them, simple as that. If it fills up you have a big problem. They try to design a PCV system that performs a similar function while letting the results drain back into the oil.

There are huge articles written about the how and why for catch cans along with all the testing evidence you could need. I'm surprised you managed a specific enough search that you didn't accidentally find some. If you don't want to use one, don't. I consider it a small investment to the longevity of my motor.

Have any proof to back up your first statement?

wireeater · Mar 22, 2017

Like everything we bolt on our cars from aftermarket sellers, they are insurance policies. Maybe, maybe not but you always get the "Why not if you love your car". Usually the people I see pushing these kind of products the most will be the people who benifit from you buying them. My view on these type of products... buy them second hand. If you get a really good deal, grab one up. Otherwise, I just wait.

Catch Cans, and Is there evidence???

lightNfast

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DontoMelbo

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AlyourPal

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hiccup

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ForYourOwnGood

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tw557

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Ebm

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HISSMAN

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ForYourOwnGood

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jacknifetoaswan

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Teezlr

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HISSMAN

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Ebm

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wireeater

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