Why do some vehicles have two identical PCV valves

[CBR.worm]

I have two Infinitis. A G35 with the VQ35DE and an FX45 with the VK45DE.

One is a V6, the other a V8.

The V6 has a typical PCV arrangement with a PCV valve at the front of the left bank connected to the intake manifold, a breather hose between the backs of the two valve covers and a breather hose from the front right valve cover into the airbox duct.

The V8 one has a PCV valve at the front of each valve cover connected to the intake manifold vacuum, and at the back of each valve cover a breather that runs into the intake plenum.

Why would they duplicate everything and have 2 PCV valves?

 

[eljefino]

My dakota V6 has two oil fill holes.

It's actually kinda nice as I can let one bottle drip dry as the other one glugs in.

I assume your grommets are the same sizes regardless of if a PCV or breather is installed. They probably want to make all their valve covers the same and not left hand/ right hand.

 

[Colt45ws]

I have to go with eljefino's explanation. Or, for some reason the engine does not breathe well enough with a conventional configuration.

 

[Kiwi_ME]

Might be more a matter of getting the required flow capacity utilizing an existing off-the-shelf part.

 

[mechtech2]

Sounds like it's for better evacuation/purging.
Be happy.

 

[CBR.worm]

I am happy

The valve covers are mirrors of each other. The PCV valve screws in with an O-ring seal, the breathers in the back have push on hose fittings.

Just seems strange that two closely related engines would have such different breather arrangements. I guess it doesn't matter, things like this always make me wonder what they were thinking. If it was a capacity thing or being able to reuse parts, or whatever. It would be interesting to look into the history of this motor, see if the engines it evolved from (the chain guide eating monster in the Q45) had similar systems or if this was added due to issues that came up.