On a stock engine with low leakdown, at what point is it necessary to drill the valve cover and add larger fittings to increase ventilation? I have a stock motor and just added an FP red ( 93 octane 25psi ) and haven't gotten on it too much due to not knowing if I'm at the point where I need to worry about this. I have a vented catch can running of of the stock fitting on the valve cover and ran my old setup like this without issue but I'm not sure if I need to do this at this point?

 

When you have a properly built engine, the larger piston ring gap along with piston to wall clearance allows more gases to make into the crankcase. No need on a stock block.

 

When your dipstick starts to move.

 

It would never hurt to go bigger. I had 2 -12 lines of my valve cover on my oem 2.0. Then on my 2.4 had 2 -12 of the VC and one -12 of the back of the block into the valve cover so oil (if there's any oil) goes back to the engine and the blow by gases go into the catch can.

 

I re-routed my PCV to the driver side of the valve cover by using a piece of hose I had in the garage. I installed the -10an fitting from STM into the passenger side vent and ran it to a catch-can.
Easy to do, increased venting, no drilling.

 

I looked at the STM fitting, is there a real advantage to using that though since it doesn't change the outlet size inside the actual valve cover, but only adds a fitting to allow a large hose?

 

No, it makes it a full 5/8" ID.

Stock motor you should be fine. Problem will come if you go VTA with the FP red

 

The inside diameter of the stock fitting is quite small, the -10 is wide open and should vent way better.

 

How is this possible? The stock valve cover nipple is only just over 1/4" outside diameter so if you pull that out of the cover and press the new one in the same hole it has to still be small initially and just get larger once its on the outside.

What do you mean by "problem will come if you go VTA with the FP red?" Are you saying to connect the other end of the can that's currently VTA back into the intake tube so there's a vacuum?

 

There is a sleeve that the PCV sits in, you pull that out when adding the fitting. It is a true -10AN or just about 5/8" ID.


Yeah, people's problems start when the go VTA with FP turbos. From what I have read it needs to stay sealed and have a line go to the air intake.

 

Ah, I was referring to the fitting on the transmission side of the valve cover since I see people drill those out and add a larger fitting.

So with a stock motor, can I just leave the pcv side alone and just take the vent on the transmission side of the valve cover and run it to a catch can and then run the other fitting on the catch can back to the intake tube or is that not the recommended thing to do with an FP red on stock motor?

 

You could.
Hopefully that will be enough.

If you drill and tap the side fitting you need to pull the baffles, it is just a pain to do and you can risk material getting into your oil and potentially hurting your motor.

 

Why do the Baffles need to be pulled? I thought you could drill it out and as long as the hole isn't too big it will stay above the baffles, unless you meant just to get all the shavings out.

 

Yep

 

Definitely gotta remove the baffles! I done mune a couple of weeks ago and the magnesium swarf is very fine and ends up everywhere inside the baffles.