[JFM-jr]

Every time I have opened my catch can there has been a measurable amount of oil in it. I would think without the catch can in place the engine would ingest this oil. With direct injection we do not have the benefit of detergent gasolines passing over and cleaning the intake valves. When I had my intake manifold off every runner had oil on the walls. I dont have a hard time seeing the benefits from using a catch can. Oil introduced into the cylinder also reduces octane and can promote detonation. My catch can is staying on the car but to each their own.

[Blade]

Originally Posted by KMPrenger

But it is there....the LT1 in the Camaro has a catch can. The ones being added are just secondary.

In my research I found out that the corvettes didn't have em, and the engines had issues similar to the ones that were on our 2010 V6s, or at least mine So maybe lesson learned for GM and they ended up providing one for the Camaro builds? I am not sure if the engine really needs a clean side can. The factory can, separates the air from the oil and drains it back in to the pan. Not sure if much else is needed.

The cans back in the DI LLT, were after market so if you wanted to put a drain in to the pan again, it was pretty damn hard. Luckily after my 2010 got rebuilt, the oil consumption was low, especially in the catch can.

To me it seems like a GM learned a lot of lessons, building the 5th gen and the C7. From engine improvements to applying the aftermarket improvements that owners of 5th gen and early C7s were utilizing in the cars when it came to exhaust, engine, suspension and even "looks" mods.

[Padre]

Padre

[kropscamaro16]

hah i dont have one didnt have one on my old cobalt ss either with was turbo and direct injection

[TJay74]

Interesting thoughts from some members, the article from Mike also has some points I am not in tune with though. Take this how you want, but I spent a lot of time dealing with the GM Chief Engineer over the entire truck division.

First off, the main reason GM didnt put a catch can on the vehicles is owner cant be trusted to empty them out. Also, if GM didn't think the catch can was needed then why are they offering them now and also putting them on some of the performance vehicles?

Second a catch can has nothing to do with oil in the MAF, at all. The catch can is installed and is well after the MAF in the scheme of things. The issue of oil fouling has gotten worse on the LTx series engines as the entire intake tract is dry now where on the LSx series engines it was wet. The LSx engines did a better job of washing the valves off, the LTx engines do not at all.

Several truck owners have had the valves looked at with coking already starting to form, also GM no longer offers a 5yr/100k mile warranty, they only offer 5yr/60k now. For GM it is a gamble, get the car to perform long enough to get it out of warranty period to where it is no longer on their dime if anything breaks down.

With that, I've had a catch can on all of my GM cars since my 2001 Firebird Formula, and I will continue to use them and keep the oil out. I don't have the detonation issues nor do I have any of the oil residue in the intake tract either.

So to each their own, the data is out there for people to make an informed decision.

[DiGiam]

Originally Posted by JFM-jr

Every time I have opened my catch can there has been a measurable amount of oil in it. I would think without the catch can in place the engine would ingest this oil. With direct injection we do not have the benefit of detergent gasolines passing over and cleaning the intake valves. When I had my intake manifold off every runner had oil on the walls. I dont have a hard time seeing the benefits from using a catch can. Oil introduced into the cylinder also reduces octane and can promote detonation. My catch can is staying on the car but to each their own.

+1
On a stock car I'm sure its not needed but i can bet when you start modding and pushing timing to the edge, your not going to want oil ingested in the combustion lowering your resistance to detonation. When i swapped intake manifolds the oil was dripping out of it.

[suzook]

Nope, never will.

[cooden]

Originally Posted by TJay74

First off, the main reason GM didnt put a catch can on the vehicles is owner cant be trusted to empty them out.

Really? But owners can be trusted to change their oil, transmission fluid, etc? That comment makes absolutely no sense. The catch can issue is nothing more than a feel good feeling. If you want to waste your money, buy one. If not, don't. There is no sane argument that can prove a catch can will make your car last longer, go faster, perform better, etc.

[Burly]

For those that have one, which one did you get?

[Atomic Ed]

It's really very easy folks, pull your throttle body off and check for oil coming in at the PVC port in the intake manifold. If you have oil, put one on, if you don't, then you don't need one.

[JFM-jr]

Originally Posted by cooden

Really? But owners can be trusted to change their oil, transmission fluid, etc? That comment makes absolutely no sense. The catch can issue is nothing more than a feel good feeling. If you want to waste your money, buy one. If not, don't. There is no sane argument that can prove a catch can will make your car last longer, go faster, perform better, etc.

Oil in the catch can canister instead of my intake manifold is my feel good feeling thats correct. If I opened the catch can and found it empty every time id agree with you but its simply not the case on my car but I cant speak for anyone else.

[TJay74]

Originally Posted by cooden

Really? But owners can be trusted to change their oil, transmission fluid, etc? That comment makes absolutely no sense. The catch can issue is nothing more than a feel good feeling. If you want to waste your money, buy one. If not, don't. There is no sane argument that can prove a catch can will make your car last longer, go faster, perform better, etc.

Because the average owner takes their car to shop to change the oil, shops don't mess with catch cans in general and pay no attention to them and or the process of emptying a catch can.

Sure the shade tree guy that does their own oil makes sure to empty it. As said, catch cans work and do remove oil from the system. My 2016 truck has a consistent 2-3 ounces of oil in it every 3k-5k miles, as did my 2014 truck, my 2010 truck, my 2008 Corvette and the other 3 previous GM performance cars.

So once again the info is it out there, just easier for the nay sayers to say they don't work. Just like the nay sayers there is no performance increase for CAI, under-drive pulleys, catback exhaust system and so on.

[JFM-jr]

Well I can agree there is no evidence that it will make the motor last longer, go faster,perfom better but the evidence does show me there is absolutely without any doubt LESS oil being introduced into the intake manifold.

I have seen oil covering the floor of the intake manifold

I have seen oil on the walls of the intake runners of the actual heads as well as the back of the intake valve.

I have removed oil from the catch can canister that is placed BEFORE any of the said components above.

Do the math is not hard to figure out this is not smoke and mirrors or snake oil but more along the lines of common sense here. It is an effort to eliminate it although it may only end up reducing it that the best that can be done. If I opened the canister and it was empty than once again common sense would prevail and tell me it is serving no functional purpose.

Im not trying to talk anyone into installing one just saying it does indeed serve a functional purpose and does what it is designed for.

[PRAY]

I will tell you that without a doubt a properly functioning PCV system with a catch can will make more power. 34rwhp and 63rwtq to be exact in one case. Actually more because we went from 3.42 gears to 3.90 gears between dyno runs. Same dyno. There was an ill working "catch can" that wasn't catching anything. This put oil on the back of the intake valves that caked up. The motor only had 8,500 miles. I flowed the heads all nasty and caked up. I then cleaned the heads up and reflowed them. Just cleaning them up was worth 140cfm throughout the lift curve. The head didn't even catch up till .600" lift. Multiply that by 8 cylinders and you have 1,120cfm of air not getting to the motor. This motor had the benefit of fuel going through it helping clean the oil. Power went from 511/445rw to 545/508rw. These flow numbers are off my SF110 bench with a 4" bore. The gap would have been much worse on a SF600 at 28". These heads went 380cfm@.700 at 28".

..........Dirty.....Clean
.100.....68..........86
.200....137........154
.300....208........228
.400....268........275
.500....310........316
.600....341........340
.700....351........353

Yes GM did put a "catch can" on the CCV side of the Camaro's. Why they didn't do it on the PCV side is kind of baffling. They ran the dirty air right into the manifold. If you don't limit that oil by using a catch can and an auxiliary PCV valve, oil is getting into the system. No if's, and's, or butt's about it. Oil vapor does not combust in the combustion cycle. I turns hard, causing detonation and sticks to everything in the intake and exhaust tract. The missing key is a check ball breather for the valve cover. You could also dual vent your catch can to the manifold and CAI. If you can't vent enough crank pressure under WOT you will get oil in the mix no matter what. DI motors are more susceptible to detonation and power loss due to the higher compression, and no cleaning effects of fuel passing over the valve. Fuel passing over the valve and sitting behind the valve helps cool the valve as well helping to stave off detonation. Caked up oil below the valve also raises compression again leading to more detonation. The motors are on the ragged edge with timing from the factory. Only time will tell. Wait till guys really start camming these things and you have real overlap. It's going to get worse.