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I posted earlier how I had about 1 Oz in my catch can after 900 miles. I checked again today at 3,000 miles and was surprised to see that it still had only 1 Oz. I suspected it might be half full but apparently I’ve had no bypass since I checked it the first time, however the oil in the reservoir is now thick like syrup. See latest pic.
Do an "Advanced search" for catch cans across from at least the C5 Forums on. You will find MORE than anyone wants to read about the topic with posts consistently split on their worth.
Take anything from the C5 forums with a grain of salt. I came from those forums back in the day and those guys are wizards at fabricating dumb *** justifications to stick anything on theirs cars. There’s also endless threads on CAI for a car with one of the shortest and straightest OEM air intakes ever produced.
When I first heard of catch cans was on C5’s which despite proof their cans were full of oil, my catch can-less C5 manages to live on with its current owner (my coworker) at 160k miles and counting.
C7 and C8 owners swear it’s because of direct injection. That’s not why C5 owners used it but it seems every generation manages to find how why they immediately need a catch can.
Last edited by Majestic94; 02-21-2022 at 06:48 AM.
^^^ Yep, those with the "If It Was Required GM Would Have Used" are often who don't check their oil or tire pressure as GM recommends. Some may not know or care that the engine must be up to temp AND running to check their oil. NO WAY EPA would allow a manufacturer to add something in the PCV system that needs dumping every 1000 to 2000 miles or it could cause emission issues! Heck the EPA in the early 1960's made manufacturers stop dumping crankcase "stuff' on the ground!
Also I recall when I dumped my "can" on my 2014 and 2017 C7 I put the spent oil in the container with a screw cap I used when changing oil! It got dumped when I changed engine oil at the local recycle center. Yep SC is a good state in that regard, we can dump about anything free. They have a large tank for oil etc. You can bring garbage free as well. What would the average C8 owner do with the oil collected, dump down the drain? In my case that would be really stuped as in our rural area we have a sceptic tank!
Jerry I’m having a hard time following your posts. On the one hand you seem to be advocating for a catch can and on the other you’re explaining why it’s not needed.
Why would you assume somebody who thinks GM engineers should be qualified to do their job don’t check their air pressure or oil? Is the average devout owners manual following owner supposed to reverse engineer the car upon purchase to come up with new maintenance requirements to follow?
There’s no reason the sump can’t act as a catch can. There’s also no reason to not add a large enough catch can to collect enough oil to make it to next oil change. GM has no problem adding DCT filter requirements or telling me to change my air conditioning desiccant every 7 years, why would they care about telling you to dump a catch can?
^^^
Read post 36 CAREFULLY! In all my posts I said GM have improved the C8 beyond even my 2017 Grand Sport dry sump system where I was collecting about 1/3 of what I collected with the same quality Catch Can in my 2014 Z51 dry sump.
Starting in 2016 GM had a much more complex PVC and crankcase evacuation system. Some of the crankcase stuff was directed to the valve covers (as my pic of the "better" C7 dry sump shows AND Don Sherman (an excellent automotive writer, engineer, Corvette racer) stated as is occurring in an article about the C8.
I also said I did not add one to my two C4's and C6 (or for that matter would not in my Street Rod with it's 850 Holley!) They has gasoline passing over the hot intake valves all the time with port injection or a carburetor.
I do laugh at all those with an early 2014/2015 C7 dry sumps AND don't/won't recognize that GM spent a lot of time and engineering effort fixing what they want to believe was a non issue with the early dry sumps. Also even Tadge said for those with the base C7 GM never added what even he acknowledged was a catch can type system to the LT1 Camaro because they did not have the dry sump option!
Yep, like Sherman defined for the C8, some crankcase "stuff" first goes back into the engine before being burned in the combustion chambers! Perhaps GM assumed rightly that those who bought the base non dry sump C7 seldom used WOT and would not "feel" the difference with what Tadge called only a cosmetic issue! (In fact, after the Grand Sport was introduced there was only a small number who did not buy the Z51, Grand Sport, Z06 or ZR1 dry sumps.)
I base what I do on the technical facts not some foolish, "If was needed GM would have added a catch can!" You don't understand the "can" is to be dumped every 1000 to 1500 miles NOT ~once a year where it's assumed most will have the engine oil/filter change done at the dealer.
^^^
Read post 36 CAREFULLY! In all my posts I said GM have improved the C8 beyond even my 2017 Grand Sport dry sump system where I was collecting about 1/3 of what I collected with the same quality Catch Can in my 2014 Z51 dry sump.
Starting in 2016 GM had a much more complex PVC and crankcase evacuation system. Some of the crankcase stuff was directed to the valve covers (as my pic of the "better" C7 dry sump shows AND Don Sherman (an excellent automotive writer, engineer, Corvette racer) stated as is occurring in an article about the C8.
I also said I did not add one to my two C4's and C6 (or for that matter would not in my Street Rod with it's 850 Holley!) They has gasoline passing over the hot intake valves all the time with port injection or a carburetor.
I do laugh at all those with an early 2014/2015 C7 dry sumps AND don't/won't recognize that GM spent a lot of time and engineering effort fixing what they want to believe was a non issue with the early dry sumps. Also even Tadge said for those with the base C7 GM never added what even he acknowledged was a catch can type system to the LT1 Camaro because they did not have the dry sump option!
Yep, like Sherman defined for the C8, some crankcase "stuff" first goes back into the engine before being burned in the combustion chambers! Perhaps GM assumed rightly that those who bought the base non dry sump C7 seldom used WOT and would not "feel" the difference with what Tadge called only a cosmetic issue! (In fact, after the Grand Sport was introduced there was only a small number who did not buy the Z51, Grand Sport, Z06 or ZR1 dry sumps.)
I base what I do on the technical facts not some foolish, "If was needed GM would have added a catch can!" You don't understand the "can" is to be dumped every 1000 to 1500 miles NOT ~once a year where it's assumed most will have the engine oil/filter change done at the dealer.
Are there actual problems with 2014-2015 engines now that 8 years have gone by?
If the “can” needs to be dumped every 1000 miles, then just make it 10 times bigger to make it to the next oil change. Or route it back to the sump….this is essentially what you’re saying the fix was which allows you to skip the catch can mod anyway. I still don’t see how this an engineering problem that only an aftermarket company has the solution for.
^^^
Did GM spend time and engineering effort the PCV and crankcase evacuation systems much better for the 2016 and later C7 Dry Sumps? You bet. Does the Camaro LT1 (all wet sumps) have and added "catch can" type system that was not added to the base C7 because, as Tadge said in a post, essentially there is an option in the C7 for a dry sump.
Will those with the base C7 who most probably seldom use WOT feel the difference to what Tadge said, was mostly a cosmetic issue, they probably won't. Is it a big problem requiring walnut shell blasting like early BMWs- NO!
Did the GM engineers for the C8 where all cars are a dry sump further improve the crankcase evacuation system- yep!
If your Tracking or have a high percentage of WOT is a catch can helpful- probably.
^^^
Did GM spend time and engineering effort the PCV and crankcase evacuation systems much better for the 2016 and later C7 Dry Sumps? You bet. Does the Camaro LT1 (all wet sumps) have and added "catch can" type system that was not added to the base C7 because, as Tadge said in a post, essentially there is an option in the C7 for a dry sump.
Will those with the base C7 who most probably seldom use WOT feel the difference to what Tadge said, was mostly a cosmetic issue, they probably won't. Is it a big problem requiring walnut shell blasting like early BMWs- NO!
Did the GM engineers for the C8 where all cars are a dry sump further improve the crankcase evacuation system- yep!
If your Tracking or have a high percentage of WOT is a catch can helpful- probably.
I don’t see what wet vs dry sump have to do with it. You can route any tubing to either a dry dump tank or a wet dump crankcase just the same.
I’m not an engine expert so I won’t argue which side of this debate is correct, but I can say that mine collects oil. Here is a photo after 3 weeks of driving with the can installed.
I agree 100%. I empty mine monthly. I get about the same amount. I would rather not burn that stuff. UPR is super easy to install and empty.
From an EPA emissions perspective, you would think the motor would run cleaner NOT burning the oil, as long as the oil is properly disposed of. I collect mine and take it for disposal when I get the oil changed in one of my cars.
Harley Davidson does the same thing, running oil blow by into the intake. ITS very common. The catch can is a simple solution however I doubt the vast majority of drivers would empty them if automakers installed them. Hard enough to get some people to even change their oil
I don’t see what wet vs dry sump have to do with it. You can route any tubing to either a dry dump tank or a wet dump crankcase just the same.
But in a dry sump there are oil/air scavenge pumps (3 in the C8) that pull "stuff" out of the crackcase. Some of the oil and mist condense on the baffles on top of the dry sump tank and return to the oil reservoir in the bottom of the tank. I proved a pic from a video. Some goes back to the valve covers before (as Don Sherman said) it goes to be burned in the combustion chamber. Some of the oil returns to the dry sump tank by the two scavenge pumps located in the cylinder head area in the C8.
The path and pressures are known by GM engineers who no doubt did a lot of testing!
The wet sump in the C7 had no scavenge pumps, just a PCV system that at modest throttle sucked the crankcase stuff into the intake manifold. Sure you can add a "Catch Can" to a C7 wet sump, some probably did but those driving aggressively no doubt opted for a C7 dry sump for the stiffer springs, larger sway bars and bigger brakes!
But in a dry sump there are oil/air scavenge pumps (3 in the C8) that pull "stuff" out of the crackcase. Some of the oil and mist condense on the baffles on top of the dry sump tank and return to the oil reservoir in the bottom of the tank. I proved a pic from a video. Some goes back to the valve covers before (as Don Sherman said) it goes to be burned in the combustion chamber. Some of the oil returns to the dry sump tank by the two scavenge pumps located in the cylinder head area in the C8.
The path and pressures are known by GM engineers who no doubt did a lot of testing!
The wet sump in the C7 had no scavenge pumps, just a PCV system that at modest throttle sucked the crankcase stuff into the intake manifold. Sure you can add a "Catch Can" to a C7 wet sump, some probably did but those driving aggressively no doubt opted for a C7 dry sump for the stiffer springs, larger sway bars and bigger brakes!
The C8 still has a PCV system that still routes oil into the intake manifold. Fact. Not arguable. And if you watch the video I posted earlier, you can see that the intake is coated in oil. Fact. Not arguable.
And even the dry sump C7 still has a PCV system that funnels oil vapor into the intake manifold. There are plenty of videos showing them coated in oil (and of the LT4 supercharger coated in oil).
....
From an EPA emissions perspective, you would think the motor would run cleaner NOT burning the oil, as long as the oil is properly disposed of. I collect mine and take it for disposal when I get the oil changed in one of my cars...
Yep wondered the same BUT EPA in the early 1960's said it was better to burn the "stuff" in the combustion chamber than have unburned hydrocarbons dumped in the air as my prior 3 cars (including the small block V8 in my '56 Chevy!)
Yep prior to early 1960's crackcase "stuff' was just dumped it he air. It was helped by having the "Road Draft Tube" close to the ground so when you were moving it was in a low pressure area that assisted pulling it out! EPA said burned hydrocarbon's are better!
The C8 still has a PCV system that still routes oil into the intake manifold. Fact. Not arguable. And if you watch the video I posted earlier, you can see that the intake is coated in oil. Fact. Not arguable.
And even the dry sump C7 still has a PCV system that funnels oil vapor into the intake manifold. There are plenty of videos showing them coated in oil (and of the LT4 supercharger coated in oil).
You're right, I had looked at the video and it shows the intake has an oil film. BUT, as Sherman stated and I show for the improved dry sump in my 2017 Grand Sport over my 2014 C7 Z51 there were optional places for the crackcase oil to drain back to the oil reservoir. (As Tadge also acknowledged they added to the Camaro LT1 - but not the C7 wet sump engines. ) The pic showed a hose from the top of the C8 Dry Sump tank goes (according to Sherman) to the valve covers. Some of the oil will route back to the dry sump tank and be put back in the oil reservoir via the two oil/air scavenge pumps in the head area.
Sure some crackcase "stuff" sill goes via the PCV valve into the intake manifold. If Tracking or racing where there is a high percentage of WOT the Catch Can may be helpful. For those that want to add for a street driven C8 -go for it! I believe even my 2017 Grand Sport, where I was collecting 1/3 the amount of oil with the same "can" I was with my 2014 Z51 dry sump, didn't need the can. In fact a report stated a small amount of oil helps lubricate the intake valve stem! I also believe GM has done and even better job mitigating he issue with the C8.
And some (not all) of the oil film in the intake could cause coking but some will also be burned.
I agree 100%. I empty mine monthly. I get about the same amount. I would rather not burn that stuff. UPR is super easy to install and empty.
From an EPA emissions perspective, you would think the motor would run cleaner NOT burning the oil, as long as the oil is properly disposed of. I collect mine and take it for disposal when I get the oil changed in one of my cars.
Harley Davidson does the same thing, running oil blow by into the intake. ITS very common. The catch can is a simple solution however I doubt the vast majority of drivers would empty them if automakers installed them. Hard enough to get some people to even change their oil
The oil in your sump isn’t anymore pristine than the oil in the catch can.
You can’t design an engine around the assumption that nobody is going to maintain it.
The C8 still has a PCV system that still routes oil into the intake manifold. Fact. Not arguable. And if you watch the video I posted earlier, you can see that the intake is coated in oil. Fact. Not arguable.
And even the dry sump C7 still has a PCV system that funnels oil vapor into the intake manifold. There are plenty of videos showing them coated in oil (and of the LT4 supercharger coated in oil).
Realistically I don’t think you’re ever going to see a perfectly dry clean intake regardless of what is added to keep it that way. But it also doesn’t mean it’s a problem.
Sir: Have you talked to any dealers whom done warranty work on direct injected engines? The internet is filled with people installing oil catch cans on a variety of vehicles. Positive crankcase ventilation combined with direct injection is a problem. How severe and rapid remains a mystery.
It modifies the emissions system and, as far as I know, they don't have CARB approval. You may not be able to pass a smog test with it installed if your state requires one.
From a practical aspect a properly installed catch can shouldn't cause any problems but a dealer/GM could give you a hard time if they felt like it.
If someone didn't empty it on a schedule I could see an argument for it "gulping" some nasty stuff into the intake all at once.
Realistically I don’t think you’re ever going to see a perfectly dry clean intake regardless of what is added to keep it that way. But it also doesn’t mean it’s a problem.
Actually been running a catch can since I had about 300 miles on it and just changed out my intake manifold this week and have 7k miles on it. Dry as a bone in the manifold so I was happy to see that. The oil I dump from that catch can is nasty!
Actually been running a catch can since I had about 300 miles on it and just changed out my intake manifold this week and have 7k miles on it. Dry as a bone in the manifold so I was happy to see that. The oil I dump from that catch can is nasty!
I am gust curious but why did you change your intake manifold?
02-20-2022, 07:12 PM
No change in 2,000 miles
Yep, those with the "If It Was Required GM Would Have Used" are often who don't check their oil or tire pressure as GM recommends. Some may not know or care that the engine must be up to temp AND running to check their oil. NO WAY EPA would allow a manufacturer to add something in the PCV system that needs dumping every 1000 to 2000 miles or it could cause emission issues! Heck the EPA in the early 1960's made manufacturers stop dumping crankcase "stuff' on the ground!
) The pic showed a hose from the top of the C8 Dry Sump tank goes (according to Sherman) to the valve covers. Some of the oil will route back to the dry sump tank and be put back in the oil reservoir via the two oil/air scavenge pumps in the head area.
