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  1. #1
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    1 out of 1 members liked this post. Yes Reputation No

    Need Help: Increasing Crankcase/Head Ventilation

    Hoping the experts on this forum can help me resolve an issue with my NA S54 E46M track car. I rebuilt the motor over the winter and overall the motor runs great. It's making 372 RWHP / 279 RWT on the TTFS dyno. Motor is healthy, compression and leak down tests are both good.
    I am running into one pretty annoying issue though. At sustained high RPM I get what I believe is excessive blow by that results in the following symptoms:
    • I get a pressure spike in the head that pushes oil out of the oil cap seal and PCV (oil/air separator) seals (both new) causing a big puff of white smoke when it hits the headers (scared the sh!t out of me first time it happened!!). This occurs at the end of a straightway where the motor is close to redline for several seconds followed by a hard downshift. I get the smoke after the downshift. I can drive around this issue by keeping the revs low (7500) and not using the engine to brake as much during downshift.
    • I get excessive oil pushing though the PCV and into the air box. This is super annoying because it only drains back to the pan when the engine isn't running and generally makes a mess.

    My working theory is that I went a little too wide on the ring gaps and blow by is causing pressure to rise/spike beyond what the stock ventilation system can handle. Surely that's a problem FI guys have resolved?!? So I'm thinking If I can improve the ventilation and reduce/release pressure in the head I could resolve these symptoms. Couple of ideas:
    • Install a catch can - Already did this using the Burger Motorsports N54 can. Stops some of the oil from reaching the air box but didn't help with pressure issue.
    • Use a bigger catch can...
    • Vent catch can to atmosphere - Maybe helps reduce pressure? Or just pushes oil out of the vent... I'd also prefer to keep a closed system.
    • Open up some of the OE connections? The PCV to Intake quick connects seem restrictive. Maybe replace them with AN fittings?

    Thoughts?? Additional ideas?? Thanks!

  2. #2
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    Anyone want to take a stab at this?

  3. #3
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    2 out of 2 members liked this post. Yes Reputation No
    I have some experience with this as I have a SC S54 and know the amount of oil you’re dealing with. The only simple way to achieve this is vent to atmosphere.

  4. #4
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    1 out of 1 members liked this post. Yes Reputation No
    VTA or die.

    I get excess pressure with a cammed stroker S54. Must be insane with FI.

  5. #5
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    1 out of 1 members liked this post. Yes Reputation No
    VTA, or run a vacuum pump........

  6. #6
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    1 out of 1 members liked this post. Yes Reputation No
    I ran a VTA setup back when I was FI and I found it to be very helpful. Make sure you use the biggest lines possible and you may even be able to surface some of my old threads for reference pictures.

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