[ANSWERED] Why No Oil Catch Can on the LT1 Corvette Engine?
06-22-2016, 11:07 AM
#1
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[ANSWERED] Why No Oil Catch Can on the LT1 Corvette Engine?
Original question is here.
Maxie2U asked:
Why did the Camaro design team decide to design in an Oil Catch Can on the 2016 Camaro with the LT1 engine? Will the 2017 C7 with LT1 engines also come with an Oil Catch Can, if not why not?
Why did the Camaro design team decide to design in an Oil Catch Can on the 2016 Camaro with the LT1 engine? Will the 2017 C7 with LT1 engines also come with an Oil Catch Can, if not why not?
Tadge answered:
To answer the second question first: No, the 2017 Corvette LT1 will not have the Camaro V8 PCV air/oil separator (what the questioner calls a "catch can") added to its oil management system. For those not familiar with the abbreviation PCV, it stands for "positive crankcase ventilation"
Even though the Corvette and Camaro share the LT1, they are very different in execution detail. The LT1 in the Corvette sits lower and very close to the ground to enable an industry-leading low profile hood and good sight lines despite a very low seated position. Having the engine close to the ground is great for keeping the vehicle's center of gravity down, but means the oil pan is relatively shallow. Having little depth in the oil pan means it is very challenging to scavenge oil in high G loading conditions. For this reason we add dry sump lubrication to our high performance models. The Camaro's higher engine position allows for a deeper oil pan and a reliable configuration for picking up oil for delivery to all parts of the engine. Thus the Camaro is able to avoid the cost and mass of the dry sump tank and resulting complexity of the lube system.
The Corvette's dry sump tank looks relatively simple on the outside but the internals are really quite complex. The top third of the tank contains a PCV air/oil separation system. On the Corvette, PCV lines route from the valve covers to the air/oil separator on top of our dry sump tank. Oil from PCV air is separated and returned to the lube system through the oil tank. The PCV separation system on Camaro V8 performs a similar function except oil is returned to the engine oil pan from the PCV separator's drain back tube. The Camaro V8 PCV air/oil separator is more complex than a "catch-can" since it not only separates oil from PCV air it provides a drain back path for this oil to be reused by the lube system. "Catch-can" systems that do not have a drain back path for separated oil run the risk of poor oil pressure performance over time as oil is removed from the lube system.
The bottom line is that both cars use optimized engineering solutions for their lube systems based on vehicle architectural considerations.
To answer the second question first: No, the 2017 Corvette LT1 will not have the Camaro V8 PCV air/oil separator (what the questioner calls a "catch can") added to its oil management system. For those not familiar with the abbreviation PCV, it stands for "positive crankcase ventilation"
Even though the Corvette and Camaro share the LT1, they are very different in execution detail. The LT1 in the Corvette sits lower and very close to the ground to enable an industry-leading low profile hood and good sight lines despite a very low seated position. Having the engine close to the ground is great for keeping the vehicle's center of gravity down, but means the oil pan is relatively shallow. Having little depth in the oil pan means it is very challenging to scavenge oil in high G loading conditions. For this reason we add dry sump lubrication to our high performance models. The Camaro's higher engine position allows for a deeper oil pan and a reliable configuration for picking up oil for delivery to all parts of the engine. Thus the Camaro is able to avoid the cost and mass of the dry sump tank and resulting complexity of the lube system.
The Corvette's dry sump tank looks relatively simple on the outside but the internals are really quite complex. The top third of the tank contains a PCV air/oil separation system. On the Corvette, PCV lines route from the valve covers to the air/oil separator on top of our dry sump tank. Oil from PCV air is separated and returned to the lube system through the oil tank. The PCV separation system on Camaro V8 performs a similar function except oil is returned to the engine oil pan from the PCV separator's drain back tube. The Camaro V8 PCV air/oil separator is more complex than a "catch-can" since it not only separates oil from PCV air it provides a drain back path for this oil to be reused by the lube system. "Catch-can" systems that do not have a drain back path for separated oil run the risk of poor oil pressure performance over time as oil is removed from the lube system.
The bottom line is that both cars use optimized engineering solutions for their lube systems based on vehicle architectural considerations.
Popular Reply
06-24-2016, 02:20 AM
Burning Brakes
Perhaps the question should be stated specifically comparing the wet sump Corvette to the wet sump Camaro.
We should be thankful Tadge is willing to answer questions posted on the Forum and try to look at the question from his perspective. A halfway answer may be because of a halfway question.
The container on the Camaro LT1 which is incorrectly called a catch can is in GM terminology an air/oil separator on the clean side of the PCV which captures oil only when crankcase pressure pushes fumes in the reverse direction. That is cleaner oil than captured in the traditional dirty side catch can.
The Camaro container several on this Forum believe to be a catch can should be thoroughly understood before the question is formulated for presentation to Tadge. Once understood, we may find the function of this container is actually built into the valve covers of the Corvette LT1.
Tadge also mentioned the difference in the oil pans on the Camaro and Corvette. I checked the Camaro Owners Manual:
http://www.chevrolet.com/content/dam...ers-manual.pdf
On page 343, the LT1 in the Camaro has a capacity with filter of 10.0 qts. so it is obviously different than the wet sump Corvette which has a capacity of 7.0 qts.
We should be thankful Tadge is willing to answer questions posted on the Forum and try to look at the question from his perspective. A halfway answer may be because of a halfway question.
The container on the Camaro LT1 which is incorrectly called a catch can is in GM terminology an air/oil separator on the clean side of the PCV which captures oil only when crankcase pressure pushes fumes in the reverse direction. That is cleaner oil than captured in the traditional dirty side catch can.
The Camaro container several on this Forum believe to be a catch can should be thoroughly understood before the question is formulated for presentation to Tadge. Once understood, we may find the function of this container is actually built into the valve covers of the Corvette LT1.
Tadge also mentioned the difference in the oil pans on the Camaro and Corvette. I checked the Camaro Owners Manual:
http://www.chevrolet.com/content/dam...ers-manual.pdf
On page 343, the LT1 in the Camaro has a capacity with filter of 10.0 qts. so it is obviously different than the wet sump Corvette which has a capacity of 7.0 qts.
Folks, Tadge doesn't have to answer ANYTHING. We should be thankful that he even replies. Just because it isn't the answer you want shouldn't imply that he is dodging us. If he wanted to dodge us, he wouldn't waste his time at all replying! It was good information that he provided. If it was generally available information, then we wouldn't have voted to have that question answered! What other car company answers users questions on a nearly monthly cadence?! Geez, let's be thankful and grateful around here.
Thanks Tadge for responding to our questions. Personally I read every one and am thankful that you take time out of your schedule to embrace Corvette enthusiast questions!
06-22-2016, 03:05 PM
#2
06-22-2016, 08:15 PM
#3
Safety Car
Yeah oddly Tadge does not discuss wet sumped Stingrays. Corvette is not synonymous with dry sump. The "vehicle architectural considerations" are a bit of a moot point. A bit of sidestepping...
This last part of his response may be a dig at catch-cans that do not put the oil back into the system, ie. aftermarket catch-cans that fill up and must be cleaned. Why else would he mention it?
"'Catch-can' systems that do not have a drain back path for separated oil run the risk of poor oil pressure performance over time as oil is removed from the lube system."
This last part of his response may be a dig at catch-cans that do not put the oil back into the system, ie. aftermarket catch-cans that fill up and must be cleaned. Why else would he mention it?
"'Catch-can' systems that do not have a drain back path for separated oil run the risk of poor oil pressure performance over time as oil is removed from the lube system."
06-22-2016, 09:20 PM
#4
Melting Slicks
This is the first answer from Tadge in which I felt he was dodging the question. It also seems that he is almost mocking people who take the issue seriously by putting "catch can" in quotes.
Personally, I see no need for a catch can, as I'm fine with his previous statement that any oil that slips by does not affect performance and is mostly cosmetic. But my personal opinion does not mean that catch can proponents do not have valid points.
Tadge's final point about worrying about a loss in oil pressure based on the tiny amount of oil caught in a catch can seems spurious, at best. It seems to me that the huge amount of oil in the system plus the nature of the dry sump would negate the loss of a couple ounces of oil.
Personally, I see no need for a catch can, as I'm fine with his previous statement that any oil that slips by does not affect performance and is mostly cosmetic. But my personal opinion does not mean that catch can proponents do not have valid points.
Tadge's final point about worrying about a loss in oil pressure based on the tiny amount of oil caught in a catch can seems spurious, at best. It seems to me that the huge amount of oil in the system plus the nature of the dry sump would negate the loss of a couple ounces of oil.
06-22-2016, 09:21 PM
#5
This is only halfway answered. I have a base wet sump engine and I'd like to know the explanation for why that engine doesn't need one.
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06-22-2016, 10:23 PM
#6
Pro
We should be thankful Tadge is willing to answer questions posted on the Forum and try to look at the question from his perspective. A halfway answer may be because of a halfway question.
The container on the Camaro LT1 which is incorrectly called a catch can is in GM terminology an air/oil separator on the clean side of the PCV which captures oil only when crankcase pressure pushes fumes in the reverse direction. That is cleaner oil than captured in the traditional dirty side catch can.
The Camaro container several on this Forum believe to be a catch can should be thoroughly understood before the question is formulated for presentation to Tadge. Once understood, we may find the function of this container is actually built into the valve covers of the Corvette LT1.
Tadge also mentioned the difference in the oil pans on the Camaro and Corvette. I checked the Camaro Owners Manual:
http://www.chevrolet.com/content/dam...ers-manual.pdf
On page 343, the LT1 in the Camaro has a capacity with filter of 10.0 qts. so it is obviously different than the wet sump Corvette which has a capacity of 7.0 qts.
Last edited by vettetwo; 06-22-2016 at 11:04 PM.
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06-23-2016, 01:23 PM
#8
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I thought he did a good job with the answer, at least he has one, and they thought about it and they tried to execute it. Weather that system works adequately, is certainly in question. Al least if i add one I will make sure it has a return line or check oil level frequently. 
06-23-2016, 02:23 PM
#9
Melting Slicks
Tadge's final point about worrying about a loss in oil pressure based on the tiny amount of oil caught in a catch can seems spurious, at best. It seems to me that the huge amount of oil in the system plus the nature of the dry sump would negate the loss of a couple ounces of oil.
https://www.corvetteforum.com/forums...catch-can.html
06-23-2016, 05:42 PM
#10
Le Mans Master
"Oil from PCV air is separated and returned to the lube system through the oil tank"
In my view, Tadge's answer confirmed the need add a catch catch to wet sump (non-Z51) LT1 engines.
In my view, Tadge's answer confirmed the need add a catch catch to wet sump (non-Z51) LT1 engines.
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06-24-2016, 02:20 AM
#11
Burning Brakes
Perhaps the question should be stated specifically comparing the wet sump Corvette to the wet sump Camaro.
We should be thankful Tadge is willing to answer questions posted on the Forum and try to look at the question from his perspective. A halfway answer may be because of a halfway question.
The container on the Camaro LT1 which is incorrectly called a catch can is in GM terminology an air/oil separator on the clean side of the PCV which captures oil only when crankcase pressure pushes fumes in the reverse direction. That is cleaner oil than captured in the traditional dirty side catch can.
The Camaro container several on this Forum believe to be a catch can should be thoroughly understood before the question is formulated for presentation to Tadge. Once understood, we may find the function of this container is actually built into the valve covers of the Corvette LT1.
Tadge also mentioned the difference in the oil pans on the Camaro and Corvette. I checked the Camaro Owners Manual:
http://www.chevrolet.com/content/dam...ers-manual.pdf
On page 343, the LT1 in the Camaro has a capacity with filter of 10.0 qts. so it is obviously different than the wet sump Corvette which has a capacity of 7.0 qts.
We should be thankful Tadge is willing to answer questions posted on the Forum and try to look at the question from his perspective. A halfway answer may be because of a halfway question.
The container on the Camaro LT1 which is incorrectly called a catch can is in GM terminology an air/oil separator on the clean side of the PCV which captures oil only when crankcase pressure pushes fumes in the reverse direction. That is cleaner oil than captured in the traditional dirty side catch can.
The Camaro container several on this Forum believe to be a catch can should be thoroughly understood before the question is formulated for presentation to Tadge. Once understood, we may find the function of this container is actually built into the valve covers of the Corvette LT1.
Tadge also mentioned the difference in the oil pans on the Camaro and Corvette. I checked the Camaro Owners Manual:
http://www.chevrolet.com/content/dam...ers-manual.pdf
On page 343, the LT1 in the Camaro has a capacity with filter of 10.0 qts. so it is obviously different than the wet sump Corvette which has a capacity of 7.0 qts.
Folks, Tadge doesn't have to answer ANYTHING. We should be thankful that he even replies. Just because it isn't the answer you want shouldn't imply that he is dodging us. If he wanted to dodge us, he wouldn't waste his time at all replying! It was good information that he provided. If it was generally available information, then we wouldn't have voted to have that question answered! What other car company answers users questions on a nearly monthly cadence?! Geez, let's be thankful and grateful around here.
Thanks Tadge for responding to our questions. Personally I read every one and am thankful that you take time out of your schedule to embrace Corvette enthusiast questions!
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06-24-2016, 10:00 AM
#12
Supporting Vendor
With all due respect to Mr. Tadge. he either pointedly did not address the question OR it was delegated to someone else and the crux of the question was lost.
We all already knew that dry sump cars used the oil tank venting as a clean side catch can; That's why the fresh air port comes out of it after all. This is not a c7 or an lt1 thing; It has been like this since the first dry sump vette. It is there, might as well use it.
-But the question was not directed to dry sump cars, since the camaro lt1 is NOT a dry sump car (neither is the lt4 ctsv3 which has this same part).
Everything before direct injection, oil consumption was almost completely an oil consumption issue, physically losing oil to the intake, oil supply goes prematurely low, and gm manages warrantied engines due to oil starvation. Now it is also performance/maintenance issue since the residue is not washed off by fuel it can and does build up significantly.
Don't get confused though, even if they added this part down the road to corvette, it only works when the airflow reverses due to blowby (full load). The part of the system used during normal (engine vacuum) street driving (99% of the time) still needs an external 'can' to 'catch' the oil.. on all gen5 engines.. well if that's something you like the sound of at least.
We all already knew that dry sump cars used the oil tank venting as a clean side catch can; That's why the fresh air port comes out of it after all. This is not a c7 or an lt1 thing; It has been like this since the first dry sump vette. It is there, might as well use it.
-But the question was not directed to dry sump cars, since the camaro lt1 is NOT a dry sump car (neither is the lt4 ctsv3 which has this same part).
Everything before direct injection, oil consumption was almost completely an oil consumption issue, physically losing oil to the intake, oil supply goes prematurely low, and gm manages warrantied engines due to oil starvation. Now it is also performance/maintenance issue since the residue is not washed off by fuel it can and does build up significantly.
Don't get confused though, even if they added this part down the road to corvette, it only works when the airflow reverses due to blowby (full load). The part of the system used during normal (engine vacuum) street driving (99% of the time) still needs an external 'can' to 'catch' the oil.. on all gen5 engines.. well if that's something you like the sound of at least.
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06-24-2016, 12:27 PM
#13
Melting Slicks
Original question is here.
And by doing the air/oil separation internally, a much higher percentage of the damaging combustion by-products and other contaminates that were in past LS engine PCV designs that used to be removed/evacuated form the crankcase is now retained with the oil being returned to the crankcase more rapidly degrading the oils ability to protect the internal engine parts. This is causing accelerated wear to most all internal components relying on the engine oil for protection. As these compounds accumulate, several stresses are put on the oil. The amount of contaminates that are smaller than the 15 microns in size is far greater now, and accumulate constantly being recirculated.
The TBN properties of the ability to neutralize acid content is quickly overcome as sulfuric acid is also now in higher concentrations as these contaminates are retained.
With the latest dyno testing on a 2015 LT1 Stingray before and after manually cleaning the intake valves of deposits has shown the same as in the past power degradation from these deposits:
I again invite Tadge, or any of his engineers to participate in taking a random LT1 engine equipped vehicle at 20k or more miles, use an independent dyno shop to come and be present ant verify all in a similar test with as many present to witness and document every step and then discuss these issues truthfully and accurately. This would go along way in building trust in what we are told by GM as the real World findings so often are so drastically different than what we are told.
And Tadge is correct, a "catchcan" is not a solution as the vast majority do so little as far as effectively separating and containing the compounds that cause the coking issues. Only a true air/oil separator system that does NOT return this concentration of contaminate laden oil back to the crankcase can address most of this as well as allow today's engines to last as long as the LS family it replaces.
06-24-2016, 01:12 PM
#14
Instructor
Agreeing with Vettetwo and Kevincol
1. My take is if you have a wet sump system (non-dry sump system) the correct way to perform proper PCV air/oil separation is to have a system thats: ...>>>
...>>> Tadge quote: >>>
>>> "... not only separates oil from PCV air it provides a drain back path for this oil to be reused by the lube system. "Catch-can" systems that do not have a drain back path for separated oil run the risk of poor oil pressure performance over time as oil is removed from the lube system.
2. Potential Lessons Learned are, if you purchase a "catch can" make sure it has a path to the oil pan with some filtering to minimize oil contamination, because you can be removing oil from the system without knowing it.
3. I do not think Tadge will supply any drama on Chevrolet wet sump engines (non-dry sump), and i do not know of any chief engineers in their right mind will, so i am very thankful about his responses and subtle messages.
1. My take is if you have a wet sump system (non-dry sump system) the correct way to perform proper PCV air/oil separation is to have a system thats: ...>>>
...>>> Tadge quote: >>>
>>> "... not only separates oil from PCV air it provides a drain back path for this oil to be reused by the lube system. "Catch-can" systems that do not have a drain back path for separated oil run the risk of poor oil pressure performance over time as oil is removed from the lube system.
2. Potential Lessons Learned are, if you purchase a "catch can" make sure it has a path to the oil pan with some filtering to minimize oil contamination, because you can be removing oil from the system without knowing it.
3. I do not think Tadge will supply any drama on Chevrolet wet sump engines (non-dry sump), and i do not know of any chief engineers in their right mind will, so i am very thankful about his responses and subtle messages.
06-24-2016, 06:36 PM
#15
Le Mans Master
With all due respect to Mr. Tadge. he either pointedly did not address the question OR it was delegated to someone else and the crux of the question was lost.
We all already knew that dry sump cars used the oil tank venting as a clean side catch can; That's why the fresh air port comes out of it after all. This is not a c7 or an lt1 thing; It has been like this since the first dry sump vette. It is there, might as well use it.
-But the question was not directed to dry sump cars, since the camaro lt1 is NOT a dry sump car (neither is the lt4 ctsv3 which has this same part).
Everything before direct injection, oil consumption was almost completely an oil consumption issue, physically losing oil to the intake, oil supply goes prematurely low, and gm manages warrantied engines due to oil starvation. Now it is also performance/maintenance issue since the residue is not washed off by fuel it can and does build up significantly.
Don't get confused though, even if they added this part down the road to corvette, it only works when the airflow reverses due to blowby (full load). The part of the system used during normal (engine vacuum) street driving (99% of the time) still needs an external 'can' to 'catch' the oil.. on all gen5 engines.. well if that's something you like the sound of at least.
We all already knew that dry sump cars used the oil tank venting as a clean side catch can; That's why the fresh air port comes out of it after all. This is not a c7 or an lt1 thing; It has been like this since the first dry sump vette. It is there, might as well use it.
-But the question was not directed to dry sump cars, since the camaro lt1 is NOT a dry sump car (neither is the lt4 ctsv3 which has this same part).
Everything before direct injection, oil consumption was almost completely an oil consumption issue, physically losing oil to the intake, oil supply goes prematurely low, and gm manages warrantied engines due to oil starvation. Now it is also performance/maintenance issue since the residue is not washed off by fuel it can and does build up significantly.
Don't get confused though, even if they added this part down the road to corvette, it only works when the airflow reverses due to blowby (full load). The part of the system used during normal (engine vacuum) street driving (99% of the time) still needs an external 'can' to 'catch' the oil.. on all gen5 engines.. well if that's something you like the sound of at least.
Well said...Tadge or someone on his staff pulled a "three-card monte" on us. Clearly my question was not directed at dry sump cars.
Last edited by Maxie2U; 06-24-2016 at 06:36 PM.
06-24-2016, 07:42 PM
#16
Le Mans Master
And Tadge is correct, a "catchcan" is not a solution as the vast majority do so little as far as effectively separating and containing the compounds that cause the coking issues. Only a true air/oil separator system that does NOT return this concentration of contaminate laden oil back to the crankcase can address most of this as well as allow today's engines to last as long as the LS family it replaces.
Well, all I know is this gunk didn't get passed onto my intake manifold.
Last edited by Maxie2U; 06-24-2016 at 07:43 PM.
06-24-2016, 07:48 PM
#17
Le Mans Master
Ok, I'm confused. Are you saying that so much "oil" can be removed by a CC the oil level could drop to unsafe levels?
06-24-2016, 08:37 PM
#19
Burning Brakes
Yeah oddly Tadge does not discuss wet sumped Stingrays. Corvette is not synonymous with dry sump. The "vehicle architectural considerations" are a bit of a moot point. A bit of sidestepping...
This last part of his response may be a dig at catch-cans that do not put the oil back into the system, ie. aftermarket catch-cans that fill up and must be cleaned. Why else would he mention it?
"'Catch-can' systems that do not have a drain back path for separated oil run the risk of poor oil pressure performance over time as oil is removed from the lube system."
This last part of his response may be a dig at catch-cans that do not put the oil back into the system, ie. aftermarket catch-cans that fill up and must be cleaned. Why else would he mention it?
"'Catch-can' systems that do not have a drain back path for separated oil run the risk of poor oil pressure performance over time as oil is removed from the lube system."
Last edited by slickstick; 06-24-2016 at 08:39 PM.
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06-25-2016, 12:31 PM
#20
Le Mans Master
To anyone that doesn't understand how silly his (paraphrasing) "..catch can's would require a drain back line to prevent low oil levels.." statement is are probably not very mechanically inclined.
The real point is these cars are sold to the masses - it would be silly to add something that you'd have to periodically manually drain or dump. There are plenty of owners that never even open their hoods - they just put in gas, drive it around until the computer tells them to change the oil.
Having an over-full catch can is worse than not having one at all.
GM has no solution for you - continue to look to the aftermarket.
The real point is these cars are sold to the masses - it would be silly to add something that you'd have to periodically manually drain or dump. There are plenty of owners that never even open their hoods - they just put in gas, drive it around until the computer tells them to change the oil.
Having an over-full catch can is worse than not having one at all.
GM has no solution for you - continue to look to the aftermarket.
Last edited by Dan_the_C5_Man; 06-30-2016 at 09:14 PM.
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