I was reading on supersixmotorsports.com about PCV valves and wondered about the one on my truck, assuming that is what that little plastic hose is running to my intake. PCV valves let oil into the air/fuel mixture lowering the octane rating. I was wondering does the 4.0's have any oil in the air mixture. Would i benefit by closing off the PCV valve with a breather and blocking that hole on the intake?

heres the .pdf i'm talking about.
Click Me!!!

 

No. They said only engines that have a high amount of blowby or ones that are running large amounts of boost.

 

First off you need to have the timing jacked up pretty high to get to the limit of 92-93 octane. And you need to have that motor at WOT quite often for this to become an issue.

I seriously doubt any ranger guys are doing this.
Besides, if you did fit into that catagory.. a splash of 100oct unleaded would make it a non-issue.

If it's a street driven truck.. just keep the valve clean and you'll be fine.

Rich

 

I just wondered. I think it would be nice mainly because The PCV valve hose falls out alot on my truck and i have to reconnect it. I dont want un-metered air going to my engine.