anyone run breather filters on their car?
- Thread starter selfinfliction
- Start date
selfinfliction;924888 said:
Bad idea. Do a search. You will find all the answers you seek.
EDIT: I'm feeling generous. http://www.supramania.com/forums/showthread.php?t=38358&highlight=PCV
i honestly wouldnt run one... to me they seem more cosmetic then anything...they will most likely fill up with oil over time.
because the pvc lines run behind the afm, all that air is metered, so running filters will allow metered air to escape, much like an uncirculated bov. i am only assuming this, so dont quote me there.
j3pz;925305 said:
If you put breathers on the valve covers, its no longer connected to the intake manifold in any way, thus no vacuum is applied to the crankcase therefore no change in airflow threw the crankcase or afm.
nosechunks;924930 said:
i'd like to hear more on the specifics on this. we don't run pcv systems on $20,000+ latemodel motors that spend 60% of the time sideways at the track. we use breathers, the only down side is low rpm idle, which is also a result of the cams, and the fact thaton occasiona you can end up with oil blowback
the engine sees positive pressure after anything more than idle/extremely low load. the only thing i can see it doing is causing extra windage at low rpms. now with an evacuator system to create vacuum, i could see helping with performance, but not removal of a stock pcv system
does anyone have experince with this subject specifically, more than just "forum knowledge" and if so, would a crank scraper solve the issues caused by the lower rpm windage issues to run breathers instead of a pcv system?
With a proper functioning PCV system, the engine crankcase is under vacuum. Therefore, there is no pressure resisting the downward travel of the piston. This isn't forum knowledge, this is how it works.
The rest of your post isn't clear so I will pretend it isn't there.
EDIT: I read your post a bit more and I think I figured out what you are saying.
The crankcase is never under positive pressure. At idle, the source of the vacuum is the throttle body. Anything off idle, the source is the accordion pipe. This means all vacuum, all the time. The amount of vacuum won't be as much as an aftermarket evac. system but it gets the job done. Still a million times better than breathers.
Info on crank scrapers can be found here.
http://www.supramania.com/forums/showthread.php?t=52351&highlight=crank+scraper+teflon
The rest of your post isn't clear so I will pretend it isn't there.
EDIT: I read your post a bit more and I think I figured out what you are saying.
The crankcase is never under positive pressure. At idle, the source of the vacuum is the throttle body. Anything off idle, the source is the accordion pipe. This means all vacuum, all the time. The amount of vacuum won't be as much as an aftermarket evac. system but it gets the job done. Still a million times better than breathers.
Info on crank scrapers can be found here.
http://www.supramania.com/forums/showthread.php?t=52351&highlight=crank+scraper+teflon
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Not to mention the simple fact that the breathers get loaded up with oil, clog and then the system can't breath...
That's bad, ok?
Yes, a catch can fills up with oil over time, it's to prevent your intercooler/piping/intake, ect from filling up with oil. Also, did you know oil lowers octane rating? Seen people with leaking CPS's on MKIV's have issues with oil seeping into the intake and causing detonation...
That's bad, ok?
Yes, a catch can fills up with oil over time, it's to prevent your intercooler/piping/intake, ect from filling up with oil. Also, did you know oil lowers octane rating? Seen people with leaking CPS's on MKIV's have issues with oil seeping into the intake and causing detonation...
selfinfliction;925359 said:
Easy there grasshoppa.
Ive run the 410 CI sprint car engines for years.
I know alot of us don't run a pcv system on the big dirt track/pavement engines.
Different design on the engines.
The 7m series needs vacuum in the crank case in order to maintain proper seal on both rubber & mechanical seals (turbo seals, piston rings etc).
If you don't have the pcv system setup right....
-Blown front or rear mains
-Blown cam seals
-Short piston ring life
-Smokey turbo performance
If this sounds like something you want, by all means go for it.
As for the windage tray/crank scraper.
I know some people here on the boards have them, but Im not sure they have ever dyno'd before and after results.
MDCmotorsports;925779 said:
i guess this is the part i don't understand how it works that it would need the system
Different type of seal(s), oiling system, and venting system compared to a race prepped small/big block chevy/ford/mopar.
selfinfliction;925796 said:
Its not just a 7m, its any motor that can benefit from a pcv system that fits its specific application.
Piston rings don't rely on the tension of the ring against the cylinder wall to seal thousands of pounds of pressure. The gases hit the ring and move outward towards the cylinder wall and the piston above the ring. the gases get in between the ring and the piston and push outward against the ring, forcing it into the wall of the cylinder. they also push down on the ring forcing the ring against the ring land, sealing the combustion chamber. This is the reason an engine needs to be loaded during initial break-in to ensure proper seating of the rings.
This pressure on top of the piston is what makes the ring seal all the pressure from combustion. Positive pressure on one side of the ring is almost identical to negative pressure, or low pressure, on the other. Using the vacuum, or low pressure created in the intake manifold to create a low pressure system in the crank case has the same effect. this seals the rings better at lower load conditions where your just cruising or idling. makes for better fuel efficiency around town or any time the engine is at low load.
The other benefit is when the pistons move such as they would create a pressure in the crank case, the vacuum makes the almost pulled or sucked into the bottom of the block decreasing resistance to movement making the engine rev or move "free-er".
These are the main benefits i know of besides keeping rubber seals from being blown out.
The only reason i can see race engines not using these systems is because there is no practical way of creating a vacuum or low pressure system to use for a pcv system.
The stock system uses both the intake manifold and the turbo inlet to create vacuum in the crank case. any time below 1 bar absolute the tube from the throttle body sucks in air threw the pcv tubing. It draws air from the accordion hose across the top of the valve covers creating a siphon across the crankcase lowering the crankcase pressure.
Above 1 bar absolute air is moving from the throttle body to the accordion hose creating a siphon effect drawing air from the crankcase lowering crankcase pressure.
The hose from the TB to accordion hose uses the same scavenging principals as a N/A motor uses in its exhaust header design using existing flowing air to influence another air mass to move.