Breather systems??

Im about to build an uprated breather system for my car.. based arround the envy car with the same -12 fittings.. whats the pros and cons of venting to atmosphere?

both kevins car and the whifbitz car vent to atmosphere as far as i can tell but ive heard others say dont vent to atmosphere... why?

your views would be appreciated:)

envy car

whifbitz

LOL my pet subject;) big can of worms territory:p do a search i'm sure you can find some entertaining reading;) i have always previously run vent to atmosphere, did this with the Supra and promptly blew the FMS, now i do not really think this had to much to do with this happening, i am more inclined to think it was down to an old/fatigued seal and me changing the oil grade to 10W x 40, however due to my paranoia and not wanting to have to replace the seal again i am now running a catch tank and Incorporated into the std closed system,

however on an big turbo application i would go either complete vent to atmosphere with up sized lines, using the extractor system using the one way hi temp valves plumbed into the turbo outlet, i think TLicense is in the process of doing this.

i was under the impression that when the breather system is linked to vacuum (induction side) that it helps to suck the gasses/blow by/crap out of the crankcase, rather than just finding its own way out (slower)

waits to be flamed

Thats only true until you get to the point when you are using enough boost to start to overcome ring seal, you then end up with the std system not coping, and over pressurisation taking place, ie not enough vacume to compensate, which is why a lot of people with big singles change it.

sorry but what do you mean by extractor system?

Its using a one way valve positioned as in the pic but would probably work better if the tube was wasted to create a pressure drop, its like a large scale PCV system but uses exhaust gas speed to suck out the crankcase pressure/emissions, a little explanation that i found, http://www.teglerizer.com/triumphstuff/emissions/emissions_exhaustscavenging.htm

http://store.summitracing.com/egnsearch.asp?Ntk=KeywordSearch&DDS=1&Ntt=crakcase+evacuation&searchinresults=false&N=115&y=6&x=42

http://www.imagestation.com/picture/sraid211/pb134c10efc9d4f894b84ee2a17f293fe/ed9bbbb1.jpg

ahh i see... i think i read that bhave was doing something along this line:)

ahh i see... i think i read that bhave was doing something along this line:)

Yes, have a crankcase evacuation system using slash cut vacuum pipes in the exhaust (Morriso system). Works well, infact I can't remove the oil filler cap with the engine running due to the vacuum!

Yes' date=' have a crankcase evacuation system using slash cut vacuum pipes in the exhaust (Morriso system). Works well, infact I can't remove the oil filler cap with the engine running due to the vacuum![/quote']

 

sounds good:) does it pull any oil into the exhaust?

Not much, my oil level isn't droping and no blue smoke, You will however get some exhaust popping/flame on the overun as you are injecting air into the ehaust stream.

Be carefull to fit the slash cuts well downstream of your wb/lambda sensors.

I am venting to atmos with a small K&N filter.

I am venting to atmos with a small K&N filter.

mine was ok with that till i went over 1.6 bar.. now it chucks out a little oil now and then.. im running 1.75bar now

If venting to atmo, I would vent well away from the hotside camcover, If you lose a piston, you could dump a litre of oil through there straight onto a red hot exhaust. Scarey.

If venting to atmo' date=' I would vent well away from the hotside camcover, If you lose a piston, you could dump a litre of oil through there straight onto a red hot exhaust. Scarey.[/quote']

 

yea good advice that... i will be venting to atmosphere:thumbs: ..

i presume that in them pics they are venting to under the car

yea good advice that... i will be venting to atmosphere:thumbs: ..

i presume that in them pics they are venting to under the car

no, the breather is run back into the intake pipe

no, the breather is run back into the intake pipe

oh yea i can just see it now in the first pic;)

oh yea i can just see it now in the first pic;)

you could just leave the intake side breather as stock connected directly to the intake manifold and run the exhaust side breather directly into the intake pipe without the need of a catch can if need be

you could just leave the intake side breather as stock connected directly to the intake manifold and run the exhaust side breather directly into the intake pipe without the need of a catch can if need be

thats what i have now but i chucks a little oil into the filter if i really hammer it;)

Yes' date=' have a crankcase evacuation system using slash cut vacuum pipes in the exhaust (Morriso system). Works well, infact I can't remove the oil filler cap with the engine running due to the vacuum![/quote']

 

You don't need that much vacuum. Too much negative pressure can be just as bad as not enough. 20 - 30 mBar is sufficient for crankcase evacuation..

Why is that Digsy? Surely its just like with dry-sump systems?

Because IIRC you can fail a crankseal by sucking air past it just like you can by blowing oil through it.

CW could comment on dry sump systems better than I. He's already posted detaisl on here saying they can be used for crankcase evacuation, but pysically not being able to take the oil filler cap off (presumably at idle speed) sounds a bit bonkers. As I mentioned, even at WOT a road-going system will pull about 20-30mBar depression in the crankcase.

I don't want to sound skeptical. I'm very interested in these exhaust based systems. I'm intrigued to know if they work equally as well throughout the entire speed / load range.

I read somewhere that a negative 7psi is max for best ring seal while not compromising crankseal implosion. I'm seeing around half that with my system.

I read somewhere that a negative 7psi is max for best ring seal while not compromising crankseal implosion....

Half a bar vacuum

Digsy, what do the engine designers in your place think about this?

I'm starting to get the impression that we are talking about two different beasts, here.

A breather system runs a slight negative crankcase pressure in order to keep blowby gases inside the engine for emissons purposes and to prevent crankcase pressurisation that might damage lip seals, etc. The piston rign sealing is engineered into the piston rings. The breather system on a road car has nothing to do with how well the piston rings seal.

These evacustion systems are starting to sound like they attack the problem from a different perspective: By creating a large crankcase depression to increase the ressure difference across the rings, thereby improving ring sealing.

I've just sent an e-mail to our head of R&D about it. Not sure when I'll get a reply.

I don't actualy vent to the atmosphere, I run the pipe from the catch tank back into the intake, to ensure I get vacum pressure.

The best thing you can do to stop FMS failure is change your oil pump and run one of our modified oil pumps combined with our breather system.

I spoke at length with Larry from SP when designing our system and it has been tried and tested on a lot of high BHP cars.

We keep both items on the shelf. You will be surprised how much the -12 lines and fittings cost when you start to add them up!

HTH

Kevin