OK, color me ignorant. What's the point? Thanks...

 

The PCV system is a nifty anti-pollution device that uses intake vacuum to suck crankcase vapors back into the intake. These crankcase vapors condense in the intake system and leave an oily residue in critical areas such as the IC and intake runners. An oil catch can simply catches the oily residue and allows the vacuum to pass. This greatly reduces the buildup of oily sludge in the intake system.

 

Thanks, Ted. Based on the install I thougth that was what this was about. Great descriptions, btw.

 

Do the oil vapors that get sucked back into the intake contribute to the buildup of carbon deposits on the piston tops? Or is that mainly due to the EGR?

 

The combustion of any hydrocarbon fuel will leave some carbon deposit regardless, although I'd be quick to point a finger at the PCV system to be an aggravating factor, simply because burning high mw hydrocarbons (oil) leaves far more residue than burning gasoline.

Are EVOs equipped with EGR? I don't conscioiusly recall seeing it.

 

Yeah, the EGR valve is located right under the throttle body.

I figure a nice water injection system will help keep our piston tops clean.

 

Hmm, I'll have to go have a look. Where is it tapped into the exhaust system?

 

I've never looked at an EVO head, but I would imagine a DSM head is similar.

If you take the exhaust manifold off, there's an opening in #4 cylinder's (the one to the far right) exhaust port that goes back to the intake side of the head and into the intake manifold and then the EGR valve. Our intake manifolds have an extra channel next to the first runner for the EGR.