Waht are pros and cons of one? Does anyone know of an actual comparison between engines with and without one?
Catch Cans For DI Engines
- Thread starter Propflux01
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I use them on my non direct injection engines (carbureted actually) and the only drawback I can think of is actually having to remember to empty it. Every time I empty mine they are only like 20% full. I check it every few weeks. Mike appears to have mainly oil, doesn't look like much condensation despite being short tripped a lot. I would rather empty that oil than have it go through the intake and end up deposited on the valves or who knows where.
Instead of posting one video, I posted the link to catch can videos so you can see the results for yourself.
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- Dec 28, 2014
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If the question is...what does valve cooking look like with or without a catch can...good luck finding actual photos and evidence, because unless I’m missing something, there really hasn’t been longterm documented evidence to compare. Why not? I have no idea, but I imagine catch can companies aren‘t financially secure/big enough to purchase two vehicles (new) and run them 50,000 miles and compare the two? Either that or they are afraid the evidence will be disputed, or not be “enough evidence”?? maybe people would look at the photos and question it, or not see enough benefit at all?
But I do think they help - I don’t think it’s super major “help”, but I do think they catch oil vapor a bit and water. Some will argue that they are not doing much of anything, that the “oil” being caught in that can is mostly water due to the temperature differences of the can and crankcase (causing vapor). Some will argue that water that is caught in that can would actually help clean the valves. Personally I think they DO HELP. I ran one for two years and yes, in the winter you do catch a lot of water, but it still has oil in it. In the summer overall everything was much less...oil and water. Mine never froze up...I was always careful about emptying it. I wouldn’t go out and buy an expensive one, you can get a $30 dollar can on amazon and the reviews on the can are quite excellent (build quality, design, effectiveness). The companies that build $200-$300 cans will tell you theirs is “better”, and they probably are, but that $30 dollar can will collect lots of oil. Trust me.
But I do think they help - I don’t think it’s super major “help”, but I do think they catch oil vapor a bit and water. Some will argue that they are not doing much of anything, that the “oil” being caught in that can is mostly water due to the temperature differences of the can and crankcase (causing vapor). Some will argue that water that is caught in that can would actually help clean the valves. Personally I think they DO HELP. I ran one for two years and yes, in the winter you do catch a lot of water, but it still has oil in it. In the summer overall everything was much less...oil and water. Mine never froze up...I was always careful about emptying it. I wouldn’t go out and buy an expensive one, you can get a $30 dollar can on amazon and the reviews on the can are quite excellent (build quality, design, effectiveness). The companies that build $200-$300 cans will tell you theirs is “better”, and they probably are, but that $30 dollar can will collect lots of oil. Trust me.
I've seen a pics of some catching a lot of moisture, but judging by the color, in the summer at least mine are catching mostly oil.
Also, not sure I'd spend the money again but I bought a cheap used $30 Amazon one from a local friend and a much better one off a member on the Hyundai forums (my fiance has a Sonata), and the one I bought from the guy on the forum for $100 used is night and day better quality and seems to catch more than the cheap one.
I’ve seen many of those, but what I haven’t seen, is say two engines with similar mileage, one with A can, one without. And actual side by side valve comparisons to each other.
My GM LTG has a factory catch can which yields very little with my driving style. The usual smelly goop of condensates and oil mist from a PCV system.
The design appears to be able to collect condensation when cool and then fully warmed up evaporates it into the intake. It’s behind the evaporator, intercooler (charge air cooler in GM speak), and radiator before the turbo.
The design appears to be able to collect condensation when cool and then fully warmed up evaporates it into the intake. It’s behind the evaporator, intercooler (charge air cooler in GM speak), and radiator before the turbo.
AZjeff
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What's the point of catching oil/water vapor then putting it into back into the intake? The whole point on a DI engine is to keep the oil vapors from baking onto the valve stems....right?
Member Z06 knows a bit about catch cans. Hopefully he can chime in and add his knowledge.
In this study removing the PCV system entirely didn't reduce valve deposits:
docplayer.net
It seems valve deposits come from combustion gasses recirculating to to the intake manifold at the beginning of the intake stroke.
Considerations on Carbon Deposit Formation in Gasoline Direct Injection Engine - PDF Free Download
Considerations on Carbon Deposit Formation in Gasoline Direct Injection Engine Gyu-Sob Cha GS Caltex Corporation Contents Introduction : Motivation & Objective of Research Preliminary Test
It seems valve deposits come from combustion gasses recirculating to to the intake manifold at the beginning of the intake stroke.
On low tech vehicles, I've used a catch can before. On high tech vehicles with very advanced systems, like my Mazda's, I have not. Honestly, no real difference in any of it, although some vehicles have known issues and I would recommend one for those, and if you own one, and are on THIS forum, you're probably already aware of the issue.
True I suppose. I put 100k miles on my last mazda di with no issue related to this though, sans can.
I made an open breathing on a E39 530 Diesel i had with the M57 engine, there was 2 benefits, 1 was that the intercooler stayed clean and empty, with the pvc intact it was half full of oil from the crankcase, the second was that the airmass went up, replacing the hot air from crankcase with cold fresh air. On idle it went up from 540mg/hub to 600mg/hub, on full throttle even more. So imo catch cans may have benefits
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I've only seen 430k miles out of a chevy 5.3. No catch can. Was still running alright. Dads workvan. Body rotted around the engine and transmission. Not a knock against it, it is expected for what it was used for.
I'm not saying it's required at all to make it that far, especially in a port injected engine, just that it can't hurt. My engine has 8700 hours also, so lots of idling and equivalent to over 500k miles of easy highway use. It burns a bit of oil through the valve seals. I'm not saying it couldn't make it to 430k miles without, but it's way to easy to throw a catch can on, just for the peace of mind.
Maybe the only difference would be 1-2mpg at 400k miles because of less carbon buildup, but that would still be a benefit.
