Eli-Z06

I'm having a problem with my catch can sucking up a lot of oil during track use, on the street it's fine but on the track it's a different story! I am now told that my catch can is not recommended for the road course. Has anyone had this problem with their C7 ZO6? After making sure the oil is not over full, (in fact hot reading was about a quarter inch up into the crosshairs on the dipstick) I am currently sucking up a full quart after 3 15-minute sessions! I must drain after each session , otherwise it will blow out the vent cap and all over my motor Brakes and Tires ! I did measure the amount that I drained from the catch can. Has anyone had this problem, then removed the catch can? Did you still consume oil at an alarming rate without a catch can? Again hard Street use and high RPM on the highway, oil consumption through the catch is very little. The car may use a quart of oil after 2000 miles of hard Street use, which I think is fine on a 800 plus horsepower motor. The car has never smoked out the exhaust and currently still doesn't, what would happen to all that oil during track use if I remove the catch can and track my car? The first time I ever track this C7 was after the catch can was installed.

Zip Corvettes

Why would a catch can not be used on a road course? My car had two of them and most do although they are not both technically being used as a catch can. The catch can is separating the oil our of the vapor so you are not burning it in the combustion chamber which is a great thing so in any situation the engine is running it would be a good thing to have one. The question is why are you filling it. So your are generally running much higher RPMS all the time on a track vs. street so this will contribute to it. Also how is it hooked up? For someone to tell you it is not recommended is crazy, show me a GT2 car that does not have one.

Eli-Z06

Well it's a Mighty Mouse wild catch can that the man himself said is not for a road course! I'm still waiting to hear back from him or my tuner to figure out the fix for this problem

MX621

"this kit should be used with extreme caution on road racing applications, overflowing of the breather onto headers can cause a dangerous fire, fitting top conversion strongly recommended " - taken from the MM website about your catch can.

Eli-Z06

​​​​​​​​​ yes the wild catch can setup is definitely not for road course use, I am hearing that you should go with the mild set up witch routes the hoses differently so it does not suck as much oil up during track use in hard cornering. I'll keep you posted on my progress, I just ordered the DeWitt 70 mm radiator and 800 watt fan, also his extra auxiliary coolant Heat exchanger to help cool coolant temperatures...

Kingtal0n

Its because catch cans are just band-aids to cover an existing problem/issue with the engine.

The right way to handle this is to fix the issue with the engine so it no longer blows oil.

There are many ways to do this but to properly implement a fix, you need to know why the oil is blowing out to begin with

Oil blows out of engines for one of two main reasons:
1. improper pcv/crankcase setup or inadequate pcv design for the demand placed on the vehicle
2. too much crankcase pressure due to damaged piston/cyl/valve/etc...

For #2 the engine needs a rebuild. Nothing you can "do" except install a can to catch oil from the bad engine until you replace the engine.

For #1 you need to pressure test the pcv system using compressor air continuously, ensure proper pcv route first.
Then, install a pressure gauge/datalogger which reads in Inches of Water on the crankcase close to the fresh-air supply tube. The gauge should have resolution in the range of +20 to -40~" H2O and be logging at a frequency of at around 10Hz. Then drive the car and see how the crankcase pressure reacts.
You are shooting for -15" to -25" of H2O at WOT (about 2" Hg). Modify the pcv system to achieve this end first.
Then, if oil still flows out of the engine through a baffle, it needs a superior baffle. You may need to cut open the baffle and re-weld some kind of trap door. Or drill some holes in it so the oil can run back into the oil pan. Some people use a actual oil return line from the head to the pan. Usually the OEM baffle is up to the challenge of PCV target is hit, but sometimes it needs help.

ckchan10

I had the MMS wild catch can on my C6 with the overflow routed inside the air filter. It also filled up in about 15 minutes in track. Very very frustrating spilling oil in the engine bay every session. This was on a brand new crate motor so it’s was not an engine issue (I did a compression and leak down to confirm).

I tried several things to fix including an extended filler neck on the valve cover (to reduce oil splash pickup versus vapors) and also Holley raised valve cover with the pickup point relocated to the top of the valve cover (behind the baffle). These two things helped a little, but still filled up too quick. My final fix was to install a secondary can that picks up the overflow from the primary can. This at lets let me finish 2 sessions before draining. Best of luck resolving your issue.

MX621

based on my experience/trial and error: when the catch can is attached to a vacuum source, it will accumulate higher amounts of oil in the catch can on the track.. on my old C5z I was filling the can every 2 sessions, when the outlet/vent was hooked to the vacuum source on the IM. so I eliminated the vacuum source and behold I was only getting a few ounces in the can after many sessions. under braking there are high rpms, with the throttle body closed, creating a very high vacuum and almost sucking the oil out of the pcv system/lines.

I believe the MM filter lets air out but not in? is that correct, allowing the crank to vent to atmosphere under WOT, but the check valve closes under vacuum? so the can is still exposed to high amounts of vacuum on track during braking. I may be incorrect here, shooting off old memory

on my current Gen5 Z/28 I'm running the elite engineering E2 can, with the factory PCV valve in play and I'm only getting a few oz's of oil in the can on track.

gimp

King: LS engines are going to blow at least a bit of oil out of the PCV system. Doesn't matter how perfect your engine is.

Eli-Z06

Well, it's always something when it comes to Women & Engines, but in my particular case I know the motor is good. It's just this catch can setup, or the way it's set up that's the issue right now. After speaking with my tuner this morning , I'm confident we'll get the catch can thing figured out. Now I'm really excited about getting the DeWitt 70 mm Radiator, his auxiliary coolant heat exchanger, and also his New I think it's an 800 watt fan!! I saw coolant temperatures around 275 the other day up at Pocono Raceway on the short tight Road Course 🏁

EdsC6Z06

I run a mighty mouse catch can on my C6 Z06 and rarely get any more than a few dribbles of oil after a hard track session? I think I have the milder version but have had nothing like what's being described here.

Eli-Z06

Yes the "mild" catch can is the one you want for track use👍

Kingtal0n

Yes, this is true for all OEM engines with OEM baffles.
This is an intended consequence of using a simple design.

Its a very good thing to see the slightest bit of oil residue with a fanning/spread out shape near the fresh air tube where it connects near the air filter. Allow me to elaborate...


This small amount of oil/light coating is negligible, and will keep the throttle body (or compressor wheel) slightly lubricated for the (100-200k) miles that is typical in daily drivers.
Most factory turbocharged engines intended to reach 200k use convoluted intake tube to help trap this slight oil coating because after 100k or 150k with no maintenance it can build up. Depending on how the maintenance is done, if it is done.
Personally I simply wash the intake tube out every 15 to 20,000 miles (turbo daily drivers whether 2.0L or 5.3L or 3.0L)

I comment here in my video about it, and show the oil residue of 20k miles:
It's at time: 14:08

Some things to note. First, this is the 'passive' side of PCV. meaning it flows whichever direction it wants; there is no check valve.
This passive side handles crankcase pressure during WOT. In order for the pcv system to work properly at WOT there needs to be an air filter and slight restriction (paper factory OEM elements slightly dirty exactly mimic the required 1.5" to 2" Hg pressure drop)
Which naturally pulls a slight relaxed oil mist from the engine over time as seen in the video. Not enough oil to puddle or actually 'get on the turbo' although I suspect and concluded many years ago that a tiny eety bit must, and does, slightly coat and keep it lubed. Which I find appealing, an appealing amount (barely enough to notice)

This 'passive' side also serves as a first warning of excess crankcase pressure (blow-by) due to blown engine, broken piston rings, bottom end issues, because it will instantly fill with engine oil under when there is a bottom end issue. If I ever found significant oil in this tube I would know there is likely a broken piston. It's a sort of 'life line' for the engine, thus the press-fit in my installation so I can repeatedly pull it off and look for traces of oil. Doesn't matter what engine we are talking about; sr20det, 2jz-gte, 4g63, LSx, they all have this tube so identify it and monitor it closely.

--------ooo£☼oooo---------
The other side of PCV system is what I call 'active' or 'cruise' side, because it has an active intake manifold suction during idle/cruise and a check valve which prevents back-flow (from intake to crankcase).
Notice the check valve shuts at WOT so this side of the PCV system has absolutely nothing to do with performance at WOT, it has no bearing on OIL Blowing out of the engine, nothing can come through this side at WOT. If you ever found oil inside this active portion of the pcv system it simply means the OEM baffle is poor quality/design, or was not maintained properly, or there is an issue returning oil from the baffle to the oil pan (carbon buildup/clogging, basically a maintenance / cleaning issue).
This is the side that should have the least trouble with oil control because it is completely separate from the violent nature of an engine at WOT.
issues in this side can be solved either with improved engine oil baffle and/or oil return strategy (from the baffle area).


Summary and how-to
1. Oil from the passive pcv often indicates problems with blow-by (engine internal parts failures)
2. Oil from the active pcv indicates problems with oil baffle construction, pcv system maintenance/cleaning, pcv lines route (height, diameter, checkvalve placement, etc...)

Solve oil from #1 by fixing the engine or replacing it
Solve oil from #2 by improving baffle or oil control strategy for idle/cruise (high vacuum, low load) or by cleaning the baffle (did you ever remove the valve covers and clean them inside the baffle by soaking in de-greaser and brushing them? ) Replace the pcv hoses (oil-crust clogs/buildup you don't see).

notes
There is a chance if you take an engine normally operated at 100KPA and 6,000rpm, and raise the pressure to 400KPA and redline to 8500rpm for example. There is a certain point at which this new WOT power/redline will overwhelm the baffle of #1 (WOT baffle) especially if the piston rings have excessive gaps for boost and large piston/wall clearances for heat. In other words, highly modified engines can't use OEM baffles well, or at all. They require special considerations, fabrication, alternative systems. The best option is DRY SUMP for those applications. It is not recommended to take a wet sump application to such extremes without properly fabricating and then measuring PCV performance, but many do.

For #2, the more high performance the engine gets, the less cruise/idle vacuum it will pull, the less oil should show up here. So it seems that there is an inverse relationship between performance and oil-related pcv inclusion for #2, that is, the more "radical" the engine, the less oil aspiration due to suction will be available at #2.

How to use a catch-can effectively from this point:
There is still a "good" way to use a can. Let say you identified the problem being the OEM baffle is insufficient and there is no pooling in the head of oil (verified) but oil seems to come through anyways at WOT in significant amounts even though the compression and leakdown are good, engine is good. And you can't afford a dry sump or to cut open and weld/fabricate the baffle system yourself.
The last option is a can, but it must be a return-style can. basically treat the can like a turbocharger drain (put a hose back to the oil pan) and use the can as a 'air/oil separator' to take oil out of air headed for the intake tube so you can still keep the WOT pcv action without the oil aspiration (for the passive side).

On the active side I would never run a can because the oil cannot be returned to the oil pan easily. You are better off modifying the baffle internally, drilling holes for drainage, take a file or grinder to it, etc... It should not take much because as above, the higher performance the engine, the less vacuum for cruise/idle, the less oil it should aspirate as long as oil isn't collecting in the baffle inappropriately (maintenance issue).

Zip Corvettes

I don't think I ever showed the new owner of my car how to clean and empty the can and I have never had a complaint about it. It does have to be routed correctly and bigger hose is not your friend in this. You are just using it to seperate the oil from the air, mine was only in between my intake valley cover and intake. My PCV lines on my valve covers were attached to my dry sump tank.

SouthernSon

As the ad says, "do it once, do it right". I have run their best on my C5Z for years and find it much better than others I tried years ago. I have no connection to the company but do like their catch can.

http://www.eliteengineeringusa.com/b...-check-valves/

nsogiba

It wouldn't be difficult to replace the fitting on the bottom of a catch can with a barbed fitting, and run a hose down to either 1) a barb welded onto the dipstick tube at an angle or 2) a bung welded into the side of the oil pan like a turbo return. You'd never have to empty a catch can again...

Eli-Z06

That would work also, yesterday we routed the hose (not the drain hose that comes out the bottom of the catch can tho) driver side PVC off on valve cover back into the Factory oil tank line in the engine compartment by the dipstick. I have another track day coming up on Monday, we'll see if this is the fix, I'll report back

NSFW

I ran my Subaru that way for years, and I am going to set up a drain for my C5, but I'm going to periodically drain it and dump it manually, rather than running it into the oil pan.

Partly because after two track days in my C5, the contents of the catch can were more fuel than oil. I don't want that stuff thinning the oil in the crankcase.

Partly because periodically checking / draining the can gives an indication of how much blow-by there is. I want to see that kind of problem early if it happens.

Eli-Z06

Actually whatever was in my catch can was straight up oil, very clean, it's not blow by due to a problem! It was all coming out of the driver's side PVC baffle due to the high G turns

Lasco001

At my 850 HP C7 Z06 never an oil problem
I have 2 Oil Catch Can THanks
Once engine block to compressor
Once both cylinder heads

But I think you have too much oil in the oil tank
My recommendation for race and trackday
10 mm below minimum marking when motor 100 °