RJP 951

David, do you know why the presence or absence of vacuum in the crankcase would affect the idle speed as I observed?

Ron

David Salama

If you leave the oil fill tube open without the check valve attached, you are probably entraining air through your fill cap into your intake via the air-oil separator and PCV system which is routed to the turbo inlet. This additional air would perhaps change your idle speed.

GaryK

David, so how is your crankcase vent hose currently routed - atmosphere, catch can, intake? Also, does it matter which direction the sump pump valve is installed in the oil filler tube?

Russ Murphy

I was talking today to a tuner who mostly does Scoobie WRX's and he said as a rule of thumb that for every 5psi of boost over stock that the crankcase ventilation capacity should double. Sounds kinda of bad for folks like me that have added 5-8psi and effectively reduced crankcase ventilation capacity. He added that the escort cosworth rally motors were able to add 25 hp to their 400 hp by substantially increasing active (vacumn) ventilation.

David Salama

Gary,

I currently have my PCV system routed to the turbo inlet just like it is suppose to. I am not sure whether I will further experiment with disconnecting it to atmosphere again, since I like the idea of creating a vacuum with turbo spool up to help evacuate the crankcase. The check valve is installed on the oil fill tube so that it pops up to allow gases to exit, but not enter, the crankcase.

GaryK

Thank you, David. So I guess it will be obvious which direction to install the check valve on the oil filler tube. With your crankcase vent hose attached to the intake as stock, are you drawing oil in thru the turbo? Did your oil filler vent reduce the amount of oil vented through this hose?

David Salama

Gary,

I'm not sure. When I had my PCV open to atmosphere without my oil fill vent, I had no oil leak out of it. It also caused me to blow out my camhousing gasket not having it on the intake to create suction! I do have significant oil burning from some unknown source when I'm on boost. Whether it is being sucked through the PCV system, I have no way of knowing. The oil fill vent did not change the amount of oil burning.

KW951

David, do you happen to know the part number for that K&N or have a good source for ordering them?

Danno

You can get these little K&N filters from motorcycle shops. They typically use them hooked directly up to the crankcase to vent pressure.

"I was talking today to a tuner who mostly does Scoobie WRX's and he said as a rule of thumb that for every 5psi of boost over stock that the crankcase ventilation capacity should double. Sounds kinda of bad for folks like me that have added 5-8psi and effectively reduced crankcase ventilation capacity. He added that the escort cosworth rally motors were able to add 25 hp to their 400 hp by substantially increasing active (vacumn) ventilation."

How to they implement the 'active' crankcase ventilation? Do they use an air pump of sort? Kinda like the smog-pumps from the '70s?

mumzer

[quote]

How to they implement the 'active' crankcase ventilation? Do they use an air pump of sort? Kinda like the smog-pumps from the '70s?[/QB]<hr></blockquote>

simple...usually with a dry sump....they will pull 15 inches of vaccuum in the crankcase...

Ahmet

I just don't understand this. I will turn down the boost to 13psi just to be safe on my own car until I figure out what's going on, but how is it that I will blow an oil pan gasket @15psi of intake boost, when there's people running way over that without problems! I mean there's only so many people with upgraded crankcase vent systems, but many people with worn engines are doing fine with a ton of boost and no oil leaks... Oil pan gasket #4 is going in my perfectly tight newly rebuilt engine this week...
Ahmet

Steve Cooper

This thread needs an idiotic entry, so I've decided to chime in

Where the heck is the crankcase vent???

Is it part of the oil filler???

Reason for my question- I'm getting a frustrating squirt of oil out of the bottom of the dipstick tube under full boost, that sprays onto the exhaust- stinky!!! - 1st noticed this when up on a dyno, and I've been chasing this problem for weeks. New dipstick tube O-rings, adjusting the tube, nothing seems to help. Best I can figure is that under boost, I'm getting excesive crancase pressure. Love to fix this with the valve above, but I can't for the life of me figure out where the valve would fit. DOH!

Been searching through my factory manuals, the chilton book, morgan's book, no luck...

Help me stop feeling soooo stoopid!

Cheers,

Steve Cooper

David Floyd

Ahmet,

I just did a leakdown to see how the rings are seating in my new engine, I have 8% leakage and while doing the check air was blowing out the oil/air seperator hose rapidly, my point is unless your oil/air seperator is clogged I don't see how your oilpan can build up pressure to blow out a gasket, unless maybe there is a boost hose routing problem ? ( boost routed to the crankcase )

I also just bought Lindsey Racings breather/catch can to install, to keep oil out of the intake.

Steve,

The vent is the hose attached to the oil fill cannister and runs over to the turbo inlet.

Steve Cooper

David,

Thanks. I'm so glad Al Gore invented the internet.

David Floyd

[quote] Thanks. I'm so glad Al Gore invented the internet<hr></blockquote>

I this part of Tennessee, we don't claim Al Gore