[urq] Too much Crankcase ventalation?
djdawson2 at aol.com
djdawson2 at aol.com
Wed Sep 5 12:21:19 EDT 2007
Ahh... this is feeling like old times? ;)
Before we start slapping me around for having a fast pig (they call them "Razorbacks" down here in NW Ar-kansas)... let's remember that the weight of said pig has nothing to do with anything at all.? That powerful I-5 20v could be bolted to my piggy, or bolted to a go-kart frame... it is irrelevant.
What is relevant is the fact that when significant acceleration occurs, oil will go where it is not wanted.? As stated before... to me, this has little to do with the breather/PCV setup, and much more to do with poor oil control within the engine... both valve cover and pan.
SO... the stock breather/PCV system WILL AND DOES?work fine... if you are OK with the concept that your turbo will be inhaling oil now and then.? If you are not OK with that, some modification will have to be made to allow the oil to separate from the ventilation flow, and drain back to the crankcase... prior to any chance of that oil being drawn into the intake charge.
Now what king of guy would let his sig-o anywhere near a 12 second street car... let alone ask her to empty his catch can?? ;)
From: QSHIPQ at aol.com
To: Djdawson2 at aol.com; vegener at post7.tele.dk; quattro at audifans.com; urq at audifans.com
Cc: benswann at comcast.net; ingo.rautenberg at gmail.com
Sent: Wed, 5 Sep 2007 9:51 am
Subject: Re: [urq] Too much Crankcase ventalation?
I might point out to you both, that pushing sloshing oil thru a breather, really doesn't dictate a PCV operational problem, this defines a bad PCV design problem.? It brings to light that big weight transferring pigs, will stuff raw oil into the breather mounted at the back of the head without a diverter.??? A catch can might catch it, but you still have the problem of oil in the breather.? IMO, every single 5psd?v8 quattro had this problem from factory new.? In fact, I had a customer complain about oil consumption to audi on his 5spd from day 1, ?to the tune that audi replaced the engine complete (now in ingos possession)...? It still sloshes oil into the breather, and the complaint documentation to audi didn't stop after the motor replacement.
The *benefit* of a proper design is that you don't get the stinky oil smell (k&n filter design), your oil consumption will reduce dramatically, and the exhaust will be cleaner.? Interesting, when you look at what Magnuson and other add-on supercharger guys do with PCV routing.? They spend a lot of time and money on getting that part of the equation just right.? Why?? Because, you start to show your sig-o how to empty a catch can, or that the oil smell is 'normal', you can lose the total purchase order on job 1.? I put proper PCV in the bin with the PS seat heater repair.? A PITA you'd rather do without when it doesn't work right, but you spend silly money to get it right for all the obvious reasons.
It's part of Carb certification to get PCV right, and I really believe that EPA will only get tighter on this wrt emissions.?
In a message dated 9/5/2007 10:35:40 A.M. Central Daylight Time, Djdawson2 writes:
This is the same experience I've had.? Mine is a '93 UrS4 with an AAN, and runs in the lower 12 second range as well.? Upon launch, oil goes everywhere... typically 1/2 quart?pushed out the breather?on each run.? The car isn't geared appropriately for the 1/4 mile, so I end up going?through the traps at over 8000 rpm.
During daily use, this is not ever an issue... but very annoying during a hard launch on the street or track.
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