Rapid Oil Accumulation in Catch Can during Autocross.
 

Allright, lets see if anyone can help me out with this one.

I have an '04 RX8 with a Weapon-R catch can (photo attached) among other mods and I have had a problem with rapidly accumulating a bunch of oil in it in a very short time. Like 13oz after 4 runs. This has happened twice.

This first time it happened was the first event of the season. Admittedly I was over-full on my oil dipstick and I think that contributed. I ran the full event and noticed some smoking towards the end. I did 3 additional fun-runs and on the last run, I felt it missing up top and gave everyone a giant smoke show as the catch-can reached a point where it poured into the intake during a hard right hand turn-around (The weapon-R catch can has its inlet and outlet on the right hand side making the g-force of the turn raise the fluid level on that side)

I cleaned everything out and ran 3 autocrosses after that with no issues and virtually no liquid from my catch can. My oil level on my dipstick was now a little bit below the 'full' mark.

This morning I had an event at a small speedway that was a very high speed course with two long-sweeping hard right hand turns on banked curves. On my 4th run, I had the same issue. Loss of power, smoke show, catch can filled with ~13oz. I cleaned everything out, called it a day and drove home 80-miles with no issues.

Oil level is now half way between the high and low marks. I took my car to red-line a couple of times on when I was a couple miles from home with no issues. No missing, idle is strong and fuel consumption is normal.

It seems like the sweeping high-g righthand turns are common issue here, but I'm concerned about why that would force such large amounts of oil up to the filler neck and into my catch can so quickly.

Is it that I simply had too much coil in the crankcase and those high right hand loads are forcing oil to places it shouldn't be? Do I have something damaged?

Any help or ideas would be appreciated. I already significantly altered the angle of the catch can in the engine bay to keep fluid away from the outlet a little bit better, but other than that, I'm stumped.

I can't explain it except for when the level was over-full.

A high level will make foam, so everything fills up with oil bubbles, including the PCV. not good for the engine either - bubbles don't lubricate well, and the filter airlocks, being the high point on the system.

Excessive crankcase pressure means that your engine is tired. That would be the only explanation really unless some thing is clogged but that is doubtful with that CC.

What's weird is the issue occurs in right handers, but your catch-can's exits are to the left. So it might just be sloshing. Also, is that catch-can baffled inside? Because if not, I'm surprised you don't get oil in the intake more often. It's a long and narrow reservoir with fluid sloshing in it, like the Bay of Fundy, and you've probably heard about their 14 foot tides.

That said, 9k is right. There aren't too many good reasons for oil to exit the engine via the PCV at all, except for blow-by. Maybe put a compression test on your calendar so you can confirm/deny that idea.

Hi there mine does the same thing escepty catch can is connected to the oil filler
neck on the left side of the engine and on the lower site of by the filler cap and no where else there is no valves ore anything. Nothing on tracks going counter clockwise however on clockwise tracks the half litter catch can fils up on less then 20 km race distance.
PRoblem is oil going up the site of the engine on the left and what after internal combustion is escaping it's enough to pull the oil out into the hoses .
my theory is that these engines produce a huge amount of condensation and that is why a low amount of blow by is able to pull the oil out and basically most of the oil in the catch can is actually condensation, I have about 250 km racing 500
km street braking in and a day on the dyno, I have drained 1 liter from the catch can but I might be able to put 1/4 liter in the engine which tells me the catch can contains about 25% oil and only on clockwise tracks .
i hope my English is understandable

The Bay of Fundy has over 14 METER tides (more than fifty of your fine American feet.)

Sure you can ...

I always have to remind people that when I first bought my RX8 in April 2005 and ran 1 qt extra oil in the sump, mistakenly believing it would keep the oil pickup covered for high G autocross use, which is what the car was bought for. I never had an engine puke oil, either then when we overfilled it or anytime thereafter when we ran the correct full level. Have never run a catch can either.

So here it is again;

puking oil = excessive blowby = new/rebuild engine time.



.