[s-cars] Quoth Oil Breathers

[Trevor Frank]

I have been looking with Brian on who has made what to solve this issue.
Currently I have my breather disconnected from the inlet to the turbo.
This is fine, but I suspect that the negative pressure that is generated
between the turbo and the maf has some performance gain.  For me without
an oil separator in the system it is risky to put something like oil
into the intake of a car making so much hp/liter.

Just to clarify oil in the intake isn't just a nuance in a high hp motor
it can cause detonation, pre-ignition and lots of carbon build up that
will exacerbate both conditions at least.  This could lead to cylinder
head gasket/head failure and all sorts of nasteis.

So why connect it to the turbo inlet.  Negative pressure in the crank
case is very sought after.  In road racing many class rules ban it.  In
drag racing there is an entire industry that manufactures vacuum pumps,
and check valves that go into the collectors to do just this.  Porsche
back in the day looked at pumping loss internally in a motor.  They
found on there horizontally apposed 6 they had something like 6-10 hp
they could gain by "flowing" the inside of the case.  Take a look at a
935-956-962 case and you will see in some cases a mirror polish.  The
less air you have moving the less the pumping losses.  Negative pressure
also promotes good sealing of the rings and less load on the oil seals.
So there is hp to be lost without it.

I propose using an air oil separator similar in design to a dry sump
catch can, or the vortexer style.  Some have gone to the trouble of
hooking it back up the sump to drain off excess oil.  If this is done I
like the idea of placing in mid plane to the motor so that in high G
corners you don't pump oil into the catch can.  If it must be mounted to
either side of the motor then I have in the past taking the feed and
drain line and crossed the lines to the opposite side of the motor
relative to the catch can.  This way you never have g forces driving oil
into the can.

-----Original Message-----
From: Bill Mahoney [mailto:wmahoney at disk.com]
Sent: Thursday, September 18, 2003 7:38 AM
To: s-car-list at audifans.com
Subject: [s-cars] Quoth Oil Breathers

Folks,
Brian Bilotti's recent post WRT  oil breather bottle was a new subject
(at least to me) and had intrigued me, but I've been too busy to inquire
further about this item until now.
One of my MM x over hose clamps had come loose so since I was there I
thought I'd pull the hose off and clean it.  I think I had about 3
tablespoons of oil in there.  So, now I can add cleaning the intake
manifold and IC to my list of things to do.
I would like to know:
1  Where would I get one of these oil breather collection bottles?
    1a  Or; how would I make one?
2 What would I use to seal off the connection to the turbo hose?
3 What are the physics involved in the operation of this device?
4 I understand the crankcase pressures will move around from
compression, but is there a way to manage this air with the idea of
perhaps gaining some ponies or at least enhancing the life of the head
gasket?

Conceptually if a breather bottle could collect this oil and keep oil
out of the intake path, it is a great idea.
Please discuss;)
TIA
Bill m  - Team member, savepizzo.org
95 1/2 Avant - with yep its 3rd clutch disc goin in today (don't ask)


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