Crank Case Breathers

[DaGr8Tim]

For you guys with experience in EFI cars and such. I know the crank case breather vents the engine. But I've been reading how people claim replacing it with an aftermarket breather that does not connect to the air box gives you like 3.5% more power.

How is that possible or are their posterior's twisted? I replaced my crankcase breather just because I didn't like the idea of blowing hot engine fumes (and a small amount of oil) into my air filter.

I've been searching the net, but can't find any hardcore data that says one way or the other if an aftermarket breather gives any real gains.

 

[falcon fanatic]

once upon a time I saw a great article about that at this website http://www.theoldone.com/
Can't remember what it said, but it made sense at the time. It had something to do with high crankase pressure causing oil and other contaminates to enter the intake via PCV and severely degrade the quality of the mixture in the cylinders, reducing power and greatly increasing the possibility of detonation. sound reasonable?

 

[MustangSix]

If you have 3.3 liters above the pistons, you also have 3.3 liters below it. All this air is being worked along with the blowby. Any energy expended by compressing the air in the crankcase is wasted, so a good evacuation system is worth a couple of hp.

Another good reason to use a PCV.

 

[DaGr8Tim]

If you have 3.3 liters above the pistons, you also have 3.3 liters below it. All this air is being worked along with the blowby. Any energy expended by compressing the air in the crankcase is wasted, so a good evacuation system is worth a couple of hp.

Another good reason to use a PCV.

I heard somewhere that gas & oil don't mix (duh), but that it lowers the octane of the gas.

 

[XFlow_Fairlane]

not to mention if you have a vac in the crankcase that the rings will seal better and oil will tend to not leak out of the seals. that is why most newer cars run a sealed crankcase.

nick