Well, until I actually see oil in the makeshift can I've got, I see no reason to fabricate the additional catch can. And before the release, my (again, with grain of salt) stock oil pressure guage was pinging the limit of pressure shown at WOT every time.

The oil pan was oozing, even after a nice silicone seal, and I was getting spraying from somewhere above the UIM, the BOV, my PCV was blowing out on throttle release, etc.

However, I'm not running anywhere near only half full on my oil level. That'd be a bit dangerous, no? But, that being said, maybe I am running too much oil in there. In addition, I've had Stage 2 oil mods (see below for specifics) done by Rob Golden, and installed CWR dual oil coolers. I have both higher volume and higher pressure than the car originally came with.

http://www.pineappleracing.com/PricelistSvcs.html

All I know is that I took a whole lot of long, high-speed rights at TWS, and discovered no leaks and no residue in the catch cap after ~150+ miles on course.

So, is there any danger I'm running oil pressures that are too *low* now. Otherwise, I'm not touching this setup. I'm happy.

-E

 

E

not clear from your posts, but did you have a functioning (not plugged or kinked) oem vent line from the filler neck to the nipple at the primary turbo inlet, and was still creating high pressure in the sump?

 

Dunno. Never checked. Might that also have been the cause of the problem?

If so, I'll check it.

Thanks for the heads-up!

But...if not, or even if it is, am I in any danger of running oil pressures down too low? I doubt it, but I'm no pro.

-E

edit: Just realized you mentioned the primary turbo inlet. I'm running single, so I don't know how that affects your statement above.

 

if the main sump vent hose to the primary turbo inlet was plugged and not fitted to a similar pre-compressor location with the single, then high sump pressure would occur unless a vented catch can was installed, as you have now done.

oil pressure should be fine.

 

Do you think you can post a picture of your catch can setup? I think I get what you are saying here, but pictures are always helpful.

- Cody

 

no pic, but it's a pur'r F54498. I cut it in 1/2, removed filter, rotated parts so both nipples come off same side. I just used a ring of mtb inner tube with a single hose clamp to rejoin the top and bottom.

I'd do a simple cam/pettit can for initial testing ... run main vent line into an old 1Q oil bottle, or a beer can.

my thing only holds about 3-4 oz max, but works for me thru a 20 min session.

 

Mahjik linked to it earlier indirectly, but here's the direct link to Crispy's set (w/ pics). Hopefully that'll help you out a bit.

http://reganrotaryracing.tripod.com/catch.htm

-E

p.s. Kevin, thanks for the response on the oil pressure. I'm gonna go see if that main vent hose was plugged this weekend. I suspect it is.

 

I have Crispy's special oil filler neck cap and a JAZ catch can PaulyDee set up for me awhile ago. The combo works fine after the excess oil has vented out (about a 1-1/2 pints). The special Crispy Cap is the key to making this setup work well though. FWIW, I run street tires, so g forces are probably less than 1?

 

I routinely see 1.2+ g with spikes to 1.3 on 245/45/16 Victoracers according to Geez! That's not on occasion, that's danged near every corner.

 

Yeah, last time I G-tech'd (take what you will from this - it's the new model), I was pulling right at about 1G on Kumho MXs (consistently slightly under). So it wouldn't surprise me if you were up around there also.

Victoracers? Those aren't street tires Damon!

-E

 

Just trying to show that on race tires I pull about 25% more g than street tires do so it makes the oil filler problem at least that much worse.

 

I kinda figured. I was just razzin' ya.

-E

 

1.2G's would be like rotating the engine 50 degrees on an engine stand, filller neck going down. add a couple degrees for body roll ....

Would be very informative to to do a test at a rebuild shop. Fill an engine (old or rebuild) to a specific level, then tilt 50-55 deg and look/probe down the filler neck to see how far it comes up. Best if plastic elbo is removed.

Then, supply some airflow into sump through an opened turbo drain line (turbo side plugged) and observe how/if level rises in fill tube (manometer like) and if there is a point where vapor bubbles up before oil reaches vents, as I suspect. Could repeat for different sump levels. A second vent line on turbo side would stop any of this manometer action or bubbling through the oil in the neck, and limit the oil rise in neck to just the static 50-55 deg tilt.

 

Now try running 275 series Hoosiers like I do and think about the lateral G-loads I might be seeing.
Interesting the observation about tipping motor at 50deg +/- and seeing how much oil "flows" into the filler neck. I do think as weel as you noted that there is a fair degree of blowby gas pushing oil vapor through the catch can as well. How much of the oil caught is from the vapor vs the oil "slosh" is any mans guess but I'd dare say it's almost all from the slosh. heck aat 50deg+ it's no wonder there's oil in the filler neck and why all real racecars use dry sumps!
Just me ramblin'
Crispy

 

Until KevinK2 mentioned it I never though of the oil filling the tube and then being driven up it by crankcase pressure. Once the oil completely fills the entry to the tube the gases are going to keep climbing up and pushing the oil in front of them. That makes perfect sense.

Seems another possible solution would be to do just as KevinK2 said: add a crankcase vent to the opposite side of the motor as well. That way in any given corner at least one of them should be "open" and allow crankcase pressure to escape. That addition alone may be all the Crispy Cap needs in order to be the perfect solution...

 

Could one tap a hole in the upper portion of the oil pan on the pax side of the motor and run a hose to the catch can?
Crispy

 

couldnt we tap a hole somewhere on the front cover for a vent? locating a vent along the centerline will prevent oil from coming up under lateral Gs, and i think its unlikley that oil comes up that high under braking.

 

Don't think that would work as you want your vent hole above the level of the oil in the pan, otherwise you have no path for the crankcase pressure to vent. I think it would be easier anyway to tap into the oil returns from the turbos: They are already present and are higher above the oil level yet still in the sump.

 

The turbo drains could be full of frothed up oil at high loads ... might be an issue for a vent line.

Agree pan hole may be too low. You don't want it to take a gulp of oil, then send it up the tube with a quick right.

I had thought of a copper tube, fixed to top of baffel in pan, that would snake up the fill tube. Pick up point would be mid way across pan. would allow venting while fill tube was partially filled with oil. but not sure if sudden right after long left would still move oil across top of baffel and into vent tube.

Front cover could have a lot of oil tossed around due to chain.

no easy answer, except for singles.

 

Kevin,
I like the idea of the tube from the pax side of the pan snaked up through the oil filler neck. This way you have a vent path from both the right and left sides of the motor *FOR PRESSURE* but it still doesn't answer the issue of oil slosh from the lateral G-loads .
The tube however wouldn't have to go so far up the filler neck that even if it did take a gulp of oil it wouldn't puke it out of the filler neck entirely. Place it just far enough up the neck to vent pressure, higher than where it would other wise be "not" venting (if that makes any sense at all)

One thing I would note is that keep in mind the underside of a rotary is not "open" like in a piston motor. The bottom of the rotary is essentially flat with a few oil return channels funnelling into the pan. The reason I stated the tap would have to be into the oil pan is a tap anywhere higher would simply be a tap into a rotor housing (water jacket). I do not think a tap in the front cover or into a turbo oil feed retrun line would work. You want to tap inot a location where there is NO oil...right? Both these locations would have oil presnt in various forms. Take a look at the pics on my webpage when I installed my own baffle platehttp://www.negative-camber.org/crispyrx7/baffle.htm
The baffle plate is almost flush with the bottom of the engine.

FWIW
Crispy

 

hopefully a baffle like yours would minimize the initial slosh. possible upgrade would be to weld on a tube for the dip stick, vs the oversized hole. Someone made a one piece multi disc plastic insert for the plastic fill neck, that would also impede slosh from getting to the vent.

good points on height of internal vent ... just high enough to stay above the 50-55 deg oil level.

the low ears of the housings are potential vent paths w/o violating the chambers, per your pics. but I just can't see any open real estate there.

another thought is to open up one of the turbo drain paths, and then feed a vent tube through the drain stand pipe, and snake it into the sump, avoiding the direct discharge point for the turbo. this creates an independent vent.

engine stand prototyping with kerosene to match hot thin oil would show if either method works, and allow tweaking the concepts.

 

Kevin,
Agree the "ears" are the only real potential location to tap into the pan area without going through the pan itself. Solving this issue would/will take much prototyping and experimentation
Regards,
Crispy