FWIW, my 340 hp NB turbo motor worked just fine with a stock (well, GTX) PCV valve and a crappy (likely not doing anything) catch can on the stock breather port, so it varies a lot by motor.

I suspect it's really about how much blowby you have past the rings.

--Ian

 

His Protege cover appears to have only a single port, vs. the stock Miata cover which has 2, PCV and exhaust side vent.

They're both 3/8, so total area is ~.22 square inches total. A lot of people upgrade to -10 line, which is is .62 square inches total. His single port is only .11. Does seem like on the low end for 400hp.

I'm no expert since I'm still dealing with some issues, but I'd add at least one more vent, but it does sound like something may have let go during the tuning or shortly after.

 

I'll third that the crank case vent lines are likely insufficient. I run two -08 lines from the ports on a VVT valve cover and still get a lot of oil misting from the catch can vent.

 

Personally my issue wouldn't rear its head on the street. I was running the PCV side (pass side) without a PCV straight into the can. I was also venting the drivers side vent to the same can VTA. This worked fine for street duty, but as soon as I got some super 200tw's on the car and started learning to drive it harder at the track it started filling up the catch can on hard left handers (which at my local CCW track was 10 out of 14 corners) . Apparently it's a somewhat known issue with the PCV side not having enough baffling so when you run it straight to a can with no PCV it will **** oil. It's intended to be used as a PCV, I.E. the valve closes under WOT and in a stock config or with a stock PCV you won't have this issue.

Anyways long story short I went crazy on my valve cover, opened up the internal ports like so (it aint pretty but it works):



With 2x -10an lines off the drivers side (in the baffled area):



To a VTA catch can, like so:



And I've never had issues again. YMMV, but this worked for me. The PCV side in my case is completely capped off since that's where the oil seemed to be coming from. The idea on this kinda venting is high volume of air allowed to vent = low velocity, and this setup carries minimal oil to the can. It also appeared to help my cam and main seal leaks. My motor was pretty fresh, and while it may be a blowby issue, it's likely because the engine builder built my motor to loose tolerances for circuit racing and high boost.

That all said, again, your issues aren't quite like mine. But I do find your use of a single vent line in the stock diameter to by very underrated for the kinda crankcase pressures I'd expect at 300+whp.

 

Thanks for the pics and ideas. That looks like a great setup.

I did a compression test today.

warmed up the car
shut it off
removed all the spark plugs
Plugged in tester
Removed CAS connnector
Held wide open throttle
Cranked for 5 seconds

Every cylinder had beetween 150-155 PSI so should I now celebrate that my motor isn't blown?

 

Get another oil cap, drill a hole in it, hook it up to a boost gauge mounted somewhere temporary, take it for a rip and see if you are making pressure.

Has the dipstick popped out on its own yet?

 

That sounds reasonable. I think mine was in the 160 range per cylinder. But more than the absolute numbers, the variance is important.

That said compression test doesn't tell you everything, but it's a good/easy check to at least confirm things aren't catastrophically damaged.

 

Thats a great idea. Will do.
Never had a dipstick pop out.

 

It's a quick and dirty way to figure out if you are building more pressure in the crankcase than your venting can handle.

Well, that's good! It usually makes for a pretty impressive mess, which I feel is something this car would probably prefer to avoid

I'd imagine if you were building excessive pressure you would see it in other places as well, like weeping gaskets and seals as oil gets pushed passed them. Something to consider anyway.

It's been a while since I caught up with this thread... what's your turbo oil feed and drain look like? EFRs, especially the earlier ones, seem to be REALLY sensitive to incoming oil pressure and don't drain particularly well. I can think of 2-3 older builds off the top of my head, including my own, where that had to be addressed. Keep at it, you'll figure it out eventually!

 

Another idea is to uncap your other breather on the back, slap a filter on that, and see if your leakage continues. That will effectively double your crankcase venting, though it may spew some oil without a can, it's worth it for a test.

 

Man, we're just full of good ideas today!

...

Well, full of something anyway

 

tHE BEst iDeAS.....

 

Not the prettiest and I need to do a second version of the catch can bracket but testing shall ensue as soon as I get tires mounted today.

Enlarged the holes in the baffles and had two -10 bungs welded on.

R888Rs 224/45/15s. The 10 year old plastic discs that acted like tires have finally been replaced.

 

Is that 890R yours?

 

yesssssssir!

Continental divide ride. 2600 miles.

 

*one of us, one of us*

https://www.miataturbo.net/insert-bs...-52890/page26/

 

sick! Just perused the thread a bit. Nice bikes. I’ve owned a lot of bikes over the years. Had a repsol cbr 1000 that sadly died in an accident being rear accident along with my t12 vertebrae. Right now my Ducati 900 lives in the house as art.

 

Nice, I fully support that haha

ADV bikes are the way though. My 890 is my favorite bike I've ever owned by far. 30k miles and counting.

COBDR this summer (again). Can't wait.

 

Dis is da way.

 

******* yeah baby!! Oil crank case pressure problem solved. Just went for a 15 minute rip. It was getting dark and the deer here are everywhere at dusk. It’s on the 93’ tune here I can’t wait to fill with e85 now. Omg after 1.5 years down it lives! Cannot explain how stoked I am. The new Toyos are night and day difference. I find myself going a little easier on giving it the beans now due to fear of glass 6 speed but man traction it’s so ******* glued to the road. Thanks curly and fire and everyone for the advice. Mucho gusto da hiney.