I know this subject has been beaten to death but I'm in need of some advice. This may be one issue, or it may be two separate issues.

Some background first. I have a GReddy Type S BOV vented to atmosphere. On clockwise (right-turning) track events, I noticed after a while of driving and cornering at speed, when shifting at redline, an oily mist would come spraying out my BOV, all over my battery and I/C pipes. I could see a little cloud escaping from the edges of the hood when this happens. This does not happen on counterclockwise (Summit Shenandoah) tracks. It does happen at right hand-centric AutoXes as well, but only after I've taken 3 or 4 runs in a row. It doesn't happen on the 1st or 2nd run after the car's been sitting.

I did the research about how oil is pulled up through the filler neck into the PCV system, etc. I installed the RESpeed baffled oil filler neck and did the 95 style PCV elimination. I thought that would fix the problem of oil being drawn through the turbo and sprayed out my BOV. Unfortunately it didn't.

I then went on to install an oil catch can off the remaining breather line coming from the filler neck. I took the car to an AutoX test&tune yesterday, a right hand turning course. Again I witnessed the BOV spray after a number of back-to-back runs were completed. I can't think of where the oil is coming from, because it's not collecting in the catch can and the clear lines to the catch can aren't showing signs of oil passing through them. I thought it might be the turbo seals leaking, but the car doesn't blow any smoke out the tailpipe even at full boost/WOT, and oil doesn't come out the BOV on left hand turning courses so it stands to reason it is not a problem with the turbos.

So that's the first problem. Today, I was digging into the issue and took out the catch can and removed the top. To my surprise there's about 1/2 inch of watery stuff in there that's sort of cloudy white with a very light orange tint to it in there along with some vapor lingering inside. It smells like hydrocarbons, but it's very non-viscous, just like water. 1/2" of the stuff from an AutoX, what the heck am I looking at here? I always knew the milky white residue that builds up on the inside of the oil cap was considered "normal" but the quantity of this stuff blows me away.

What the heck is going on with my car and how do I stop it?

Thanks!

Oh and for your efforts in reading this far, here's a video from the AutoX:
http://vimeo.com/3915015

 

I have similar problems with my car during my track events. I didn't see you mention it, but I'm assuming you're still on the stock twins?

First, thanks for confirming that the RE-speed oil neck works. I have the stock neck with the PVC eliminated and run to a catch can and during a 20 minute session at a clockwise track it'll put 1/2-3/4 of a quart of oil in the catch can. The "gunk" you're getting is what SHOULD be getting into the catch can so I'd say you're ahead of the game there. I had asked some of the more senior members that tracked cars with stock twins and they all said that they couldn't find a way around the problem of dumping oil during a track session and to just get used to it.

So...I'd say your only problem is the oil out of the BOV. I have this as well. I hate to ask, but are your turbos stock? Mine are, and I believe the oil seal can't handle the heat/abuse of constant boost for 20-30 minutes anymore and it's just letting oil blow thru the intake. I don't notice it until about 5 or so minutes on the track....and it likes to "sneeze" out of my vented hood onto my windshield so I definitely notice My turbos do however produce small spurts of smoke otherwise which gives me the indication they're the problem.

However with your situation and it only happening on clockwise configurations is interesting. Since there is not a vent on the right side of the motor and putting one there is the solution for all the single-turbo guys.....I wonder if the oil flowing up/blocking the fill neck is causing extra pressure which is causing oil to blow past the turbo seals temporarily....someone with more experience and mechanical know-how will have to post up on that theory.

 

Thanks for taking the time to respond, your answer is very insightful. I hadn't even considered the possibility that no oil in the catch can = REspeed filler neck is doing its job. Last weekend was the first time I'd used a catch can. That is good to know.

Yes, I am running the stock sequentials at stock boost levels. They have 90k miles on them and otherwise seem to function perfectly.

I think at this point I will have to run another left-turning track event to validate my findings. One other possibility that occurs to me is that perhaps residual oil has been accumulating in my intercooler and after enough time making right hand turns, it pools in the outlet end-tank and gets drawn out by the charge air? That doesn't seem too likely because I drained the intercooler for at least a week over the winter. Another possibility... perhaps the stuff coming out the BOV is 90% crankcase [fuel|oil|water vapor] that's been vacuumed out by the turbo. My only reasoning for claiming it was oil is because when I wipe down the engine bay the paper towels end up dark colored. That could be other engine grime mixed with the milky condensate and not motor oil at all. The catch can could only be capturing a portion of the crankcase gasses, because the can isn't baffled at all internally.

 

If it were my car, I'd do a fresh oil change right before an event where this happens to see if that has any effect on what ends up in the catch can.

Dave

 

FWIW the oil was completely fresh before this AutoX event. I change the oil after every track event (usually ever 500-1000 miles on the odo) and this was the "break-in" of the season. I always use 20w50 in the car. I suspect that may result in increased oil pressure initially till it gets heated up. Of course the problem in question only manifests itself when the car is completely hot.

 

I'm assuming from your statements that you have your catch can routed back to your intake pipes? Mine just dumps to the tank and then the tank has a breather filter to the atmosphere. You might try disconnecting the connection to your intake and seeing if that makes a difference, then you'd at least know if it's residual from the catch can.

Also, where is your blow off valve located? I'm still in the stock position so I think that I see a good amount of oil come out of my BOV, if it was located in my intercooler outlet pipe I'd probably get less due to the distance of the oil accumulating different places in the pipes/intercooler.

I definitely feel your pain on trying to fix/test for this issue too. I haven't been able to replicate it at all on the street, but it's a noticable problem on the track (I lubed my entire engine bay/car one session by over-flowing the original catch can I had). It's frustrating to have to try fixes, but not be able to test them before the next track day.

 

I've blocked off the PCV from the filler neck to the intake manifold. The catch can is routed back to the stock breather piping that goes to the turbo so it's always under a vacuum. I thought about venting the catch can to atmosphere, but to properly evacuate the crankcase of all the nasty stuff I read somewhere that it really needs to be under vacuum.

The BOV is located on the GReddy elbow just before the throttlebody.

Yea, it is frustrating and my biggest concern is that all the oily mess that comes spraying out all over my engine bay will someday catch fire burn the car to the ground. After a single track session enough nasty has come out and coated my whole engine that smoke comes wafting from under the hood near the firewall as it evaporates off the motor. A legitimate concern I think

 

What kind of camera are you using, Matt?

 

Took a lesson from you and picked up a used Aiptek A-HD (older model) on eBay for $49. Added the wide angle lens and made a custom power cord for it so it'll record while charging. Still need to address the sound because the built in mic is pretty terrible. Thinking of wiring an external mic to it...

 

link to the RE-speed oil neck?

Here is an outline of the factory FD crankcase ventilation system:



The PCV valve does not function under WOT, so all the oily crap is recirculated before the turbos. The BOV is also recirculated. I suspect that this car has had this problem all along, but it is essentially hidden by the fact that Mazda just burns all the oil up through recirculation.

Interestingly enough, here is an outline of the factory 87-88 turbo FC crankcase ventilation system:



There is an extra crankcase vent on the firewall side of the middle iron for 2nd generation cars (see the solid arrows in above diagram). Not only that, but this Mazda diagram seems to indicate that most of the WOT crankcase pressure is relieved on that car through this port on the middle iron.

My 2nd gen runs both these vents to the catch can and never has any of the problems on the track that you guys are describing, although it does have an aftermarket oil pan baffle. I am mystified that Mazda would remove this crankcase vent on a later model car that would actually have more crankcase pressure.

 

http://mrcmfg.com/catalog/product_in...roducts_id=258

 

Matt,
If oil's in the BOV, then there should be oil in the intake tract. The filler neck and BOV wouldn't get oil from the same source. Might try using a stock BOV plumbed back to the intake.

 

It was my understanding that whatever comes out the filler neck vent and isn't captured by the catch can gets pulled through the turbo and regurgitated through the intercooler piping to be burnt off by combustion in the engine. Since I didn't see any evidence of oil in the catch can, I was wondering if there could possibly be another source of oil being drawn into the I/C piping (besides the turbo seals).

 

Matt, how much oil does your car consume during a session?

BTW I wouldn't worry about the oil catching fire. You should see how my engine bay looks after a session on track.

 

A marginal amount. I can go a whole weekend and not have to top off.

If there really is no solution to stuff spraying out the BOV, I may do as Peter suggested and get rid of the Type S in favor of stock. I'd have to block off or replace the greddy elbow though. I only got that BOV because it basically came free with the elbow when I bought it. My current intake piping has no provisions for recirculation so it'd probably just change the side of the engine bay the spray comes out on to the hot turbo side anyway ;P

 

How is your plumbing configged? I have a line from filler neck to catch can, and then another from catch can to primary turbo... can always fills first.

 

I don't have a catch can or the special filler neck, and mine will take it down to about the low line on the dipstick over the course of 2-3 sessions, but then it won't drop any more no matter how much I run. This is obviously loss through the filler neck. I have no cat, so it blows smoke when it's burning off oil. I have the stock BOV vented to atmosphere, and I get the spray all over the place too, but I recently checked my intercooler and it only had maybe 1 tsp oil in it after a whole season. Anymore, I just don't fill it much past the low line on the dipstick and it hasn't really been a problem. I considered a catch can, but didn't want to deal with it filling up and leaking.

 

How is that one routed?

Thanks.

 

A catch can isnt going to eliminate the oil that is being discharged via the BOV as ptrhahn already pointed to - the oil being discharged from the BOV is most likely oil bypassing the turbo oil seal or your oil o-ring int he engine has failed

 

Are both sides of the motor vented?

If not, long right handers can let enough pressure build up to blow some oil.

I have a catch can that is routed to the right side of the block as well as the left. It took quite a while to accumulate enough oil to drain.

There's a few threads on oil catch cans.

Here's one that may help: https://www.rx7club.com/race-car-tech-103/vented-non-vented-oil-catch-can-729453/

 

That's how mine's set up too.

 

Considered, but when you think about it, those possibilities don't make sense because my problems only happen on right hand turning tracks.

 

Interesting -- still using stock twins and stock vent location. Don't really want to drill/tap my block for another vent!

 

Still having twins would require more creativity.

Mine just required unblocking a blocked of port for the twins.

 

yeah, the only way I've seen the other side of the motor successfully vented on the other side with twins would be to tap the front cover. I suppose I'll do that if I ever need to rebuild, but I have yet to see another option that works well without going single.