[urq] Too much Crankcase ventilation? - More

Wed Sep 5 18:19:33 EDT 2007

That's because we don't really know what the #%$@ we're talking about.

-----Original Message-----
From: Brandon Rogers <brogers at terrix.com>
To: djdawson2 at aol.com; QSHIPQ at aol.com; benswann at comcast.net; vegener at post7.tele.dk; quattro at audifans.com; urq at audifans.com
Sent: Wed, 5 Sep 2007 4:19 pm
Subject: RE: [urq] Too much Crankcase ventilation? - More

Whats up with all the question marks?
?
?

Brandon

-----Original Message-----
From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com] On
Behalf Of djdawson2 at aol.com
Sent: Wednesday, September 05, 2007 4:01 PM
To: QSHIPQ at aol.com; benswann at comcast.net; vegener at post7.tele.dk;
quattro at audifans.com; urq at audifans.com
Subject: Re: [urq] Too much Crankcase ventilation? - More

Dear PCV Boy,

The valve cover's use?on the AAN engine is simply as a tube for the PCV
system.? It is essentially a solid pipe running through the valve
cover... no venting to the area covered by it.

I encourage you to remove an AAN valve cover.? If you plug one nipple,
and blow air into the other nipple, it has nowhere to go.

Dave

-----Original Message-----
From: QSHIPQ at aol.com
To: benswann at comcast.net; Djdawson2 at aol.com; vegener at post7.tele.dk;
quattro at audifans.com; urq at audifans.com
Sent: Wed, 5 Sep 2007 2:55 pm
Subject: Re: Too much Crankcase ventilation? - More

Ben

I'll address this to you since you started it, but Claus and Dave's
responses are in here as well.

?

First, a look at how the 20vt works.? Indeed there is PCV at the valve
cover Dave, at least on a 95.5 S6, I just looked.? It's the little hose
below the turbo intake breather?hose connection?at the back of the valve
cover.? It goes down to the vacuum valve at the crankcase, where
crankcase, valve cover and intake feed all converge at the crankcase '8
ball'.? According to TST 218, during high vacuum (idle) the PCV is drawn
into the intake via the ck valve at the intake manifold.? During low
vacuum or boost, the PCV is drawn into the inlet side of the turbo via
the pressure control valve.

?

This means that a larger turbo with the same size inlet pipe will have
more vacuum pulling on the pressure control valve.? It also means that
oil sloshing in the head and oil sloshing in the crankcase, has a really
good chance of getting sucked up at idle, just off idle, launches?and at
a higher than stock boost level.? Not sure why audi mounted all this so
low on the block, it's really conducive to sloshing issues of both the
block and the head (guessing the head causes more oil issues than the
block, since that 8ball crankcase design on the block has been around a
long time without issue).

?

WRT what to use for a modded/improved PCV, I would highly suggest the
supra twin turbo app (don't forget the gasket) 1993-1998.? It operates
per the website I provided, and it has a really good turbo shutoff
action on it.? And, discounted, it's less than 10 bucks.? I noticed that
the Mustang supercharger boys use this valve as the 'standard' as well.?

?

For hookup on your 10vt Ben, I would consider putting this valve in
place of the stock urq pcv valve, and mount it above the valve cover
somehow.? I would think you could machine up a simple block that would
tie all this together with the stock system.? Since the supra twin turbo
uses a really high compression ratio, I'd bet the match to the orifice
of that PCV valve would be really good.

?

What may screw all this up, is the amount of vacuum present at the turbo
inlet.? That's pretty key to making sure the breather is acutally
breathing air vs fighting an alternative vacuum source.? Claus, wrt
octane vs oil vapor... In a properly designed PCV system, there
shouldn't be enough blowby to make this significant.? And if you read
the site I posted, if 70% of that vapor is unburnt HC, you aren't
affecting octane much at all.? IME, running back to back PCV connected
vs not, there appears to be no significant difference in dyno output
(read: just another run can result in the same change).

?

Martin, PCV is one of my interests along with the black mysteries?of
Torsen operation.? Call me PCV boy if you want, but I really believe
there are very few that really understand how it works,?more
specifically,?how to work it.? I don't see closed loop PCV as a bad
thing, and both Eaton and Magnuson advocate running PCV closed loop to
carbon treat the blades of the SC and put a coating of deposits in the
plenum to screw clearance.? I don't see why this theory also wouldn't
hold true for a turbo as well.

?

Scott Justusson

PCV Boy formerly known as Torsen Boy

'94 Landcruiser Supercharged with modified PCV 

?

?

?

?

?

?

?

In a message dated 9/5/2007 3:19:48 P.M. Central Daylight Time,
benswann at comcast.net writes:

Thanks Scott,

This is helpful in furthering my understanding.? I thought I knew what a
PVC valve did and how the system functions - or is supposed to.? I think
by the end of this I'll really understand.? Until the next time that is.

So any recommendation on which valve to use - if you go to FLAPs there
are at least 50 different versions of valves and even more variation
when you get into model, port size and orientation.? Some are simple
check valves and some are apparently much more.

We have to presume that I no longer have the proper remnents of the UrQ
setup, and that the restriction would be significantly different.? I
checked out the early TQ implementation and it works because there is
just a slight venture vac. Used inside the metering box.? With speed
density, no such port.

Ben

?

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