Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: woodsy_mv6 on 14 May 2009, 12:25:01

Title: And breeeeeeeath!!
Post by: woodsy_mv6 on 14 May 2009, 12:25:01
Following a discussion with Andy (VX1) at the weekend, I was wondering about the implications of venting the breathers to the atmosphere as apposed to poisoning the inlet....

My understanding is that it doesn't go full circle, and all does indeed get dumped in the plenum.. Anyone confirm??
Title: Re: And breeeeeeeath!!
Post by: megaomega123 on 14 May 2009, 12:29:46
I think you may run into problems with the crankcase pressure as that is the sole purpose of the breather system. I am sure it will be a big difference in the pressure at the plenum and atmospheric pressure.
Title: Re: And breeeeeeeath!!
Post by: Cybertrucker on 14 May 2009, 12:32:48
Isn't it a legal requirement that crankcase emissions get burned in the cylinders rather than venting to atmosphere?   :question
Title: Re: And breeeeeeeath!!
Post by: woodsy_mv6 on 14 May 2009, 13:11:40
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I think you may run into problems with the crankcase pressure as that is the sole purpose of the breather system. I am sure it will be a big difference in the pressure at the plenum and atmospheric pressure.
I did wonder about a lack of preasure, but figured my Ex-polac car spends most if its time at WOT and therefore atmospheric pressure....

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Isn't it a legal requirement that crankcase emissions get burned in the cylinders rather than venting to atmosphere? :question
Seriously doubt it.
The reason I breached it to Andy was due to the fact I've seen many other engines run them (modern or otherwise, turbo or otherwise).
Didn't say I was gunna do it anyhow, just interested in the implications for now :y
Title: Re: And breeeeeeeath!!
Post by: Abiton on 14 May 2009, 13:18:31
If WOT = atmospheric pressure, what causes air go into your engine?  ;)

Pretty sure it's true about no venting to atmosphere.  Good MOT station should fail it.
Title: Re: And breeeeeeeath!!
Post by: woodsy_mv6 on 14 May 2009, 13:45:25
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If WOT = atmospheric pressure, what causes air go into your engine?  ;)
Because any more would require a charger ;)
Title: Re: And breeeeeeeath!!
Post by: Abiton on 14 May 2009, 14:00:37
Point missed, I fear.

For air to flow from A to B, the pressure at B has to be less than at A.

Therefore, even at WOT, the pressure in your manifold has to be lower than atmospheric.
Title: Re: And breeeeeeeath!!
Post by: doz on 14 May 2009, 14:22:55
If your worried about the environment etc why not just plumb in a descent catch tank and still vent to the plenum from the tank? Failing that just vent to atmosphere and dump a pipe in a coke can. I've seen both done  ;) after all your only trying to get rid of "positive" crank pressure so don't really matter where it goes
Title: Re: And breeeeeeeath!!
Post by: woodsy_mv6 on 14 May 2009, 16:01:34
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Point missed, I fear.

For air to flow from A to B, the pressure at B has to be less than at A.

Therefore, even at WOT, the pressure in your manifold has to be lower than atmospheric.
I think you'll find it's the target that has the low preasure (i.e. the cylinders themselves). The MAP will be 1 bar at WOT!
Title: Re: And breeeeeeeath!!
Post by: woodsy_mv6 on 14 May 2009, 16:01:40
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If your worried about the environment etc why not just plumb in a descent catch tank and still vent to the plenum from the tank? Failing that just vent to atmosphere and dump a pipe in a coke can. I've seen both done  ;) after all your only trying to get rid of "positive" crank pressure so don't really matter where it goes
Completely forgot about coming straight to you regarding this one Dave, what you're rally experience........ And since you're coming to terms with the V6 and all ;D
Title: Re: And breeeeeeeath!!
Post by: Abiton on 14 May 2009, 16:35:17
Quote
Quote
Point missed, I fear.

For air to flow from A to B, the pressure at B has to be less than at A.

Therefore, even at WOT, the pressure in your manifold has to be lower than atmospheric.
I think you'll find it's the target that has the low preasure (i.e. the cylinders themselves). The MAP will be 1 bar at WOT!

In my engine the cylinders communicate with the manifold via the intake valves, thereby reducing the pressure in the manifold below atmosphere. Maybe not by a lot, but some. :)
Title: Re: And breeeeeeeath!!
Post by: doz on 14 May 2009, 17:01:57
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Quote
If your worried about the environment etc why not just plumb in a descent catch tank and still vent to the plenum from the tank? Failing that just vent to atmosphere and dump a pipe in a coke can. I've seen both done  ;) after all your only trying to get rid of "positive" crank pressure so don't really matter where it goes
Completely forgot about coming straight to you regarding this one Dave, what you're rally experience........ And since you're coming to terms with the V6 and all ;D


It's drivin me mad Chris. I did the spark plugs the other day. Did the first 3 ok but was really stumped about the other 3 without em all being in line like  ::) took me ages to find em  :-[