PCV HOSE Size/ Pressure

[ZC-DMAX-LMM]

With -8an pcv fittings does it need to increase to a 5/8” hose from the fitting or will a -8 an to 1/2” barbs be enough? Assuming there will not be any pressure, also contemplating removing the pcv valve/diaphragm.


Sent from my iPhone using Tapatalk

 

[Chevy1925]

With -8an pcv fittings does it need to increase to a 5/8” hose from the fitting or will a -8 an to 1/2” barbs be enough? Assuming there will not be any pressure, also contemplating removing the pcv valve/diaphragm.


Sent from my iPhone using Tapatalk

you will have pressure. opening up the hose right after the fitting is a good idea, helps promote flow. are you going to be feeding it back into the intake or leaving to open air? attempting a venturi tube? vac pump?

 

[ZC-DMAX-LMM]

you will have pressure. opening up the hose right after the fitting is a good idea, helps promote flow. are you going to be feeding it back into the intake or leaving to open air? attempting a venturi tube? vac pump?

I switched from hose barb to -an pcv fittings. Previously vented to atmosphere, considering running to downpipe with another fitting or back to atmosphere

 

[ZC-DMAX-LMM]

you will have pressure. opening up the hose right after the fitting is a good idea, helps promote flow. are you going to be feeding it back into the intake or leaving to open air? attempting a venturi tube? vac pump?

What pressure does a stock internals motor usually produce?
I’m finding -1.5 kpa to +4 kpa. So any hose can handle the pressure? Not even a 1 psi tolerance.

Sent from my iPhone using Tapatalk

 

[JoshH]

It's not so much the pressure on the hose that I would be worried about as much as the restriction a smaller hose causes increasing pressure in the crankcase.

 

[ZC-DMAX-LMM]

It's not so much the pressure on the hose that I would be worried about as much as the restriction a smaller hose causes increasing pressure in the crankcase.

To make sure I understand, if the spring and diaphragm are removed. There isn’t a way for pressure to be built up in the crankcase from any resistance in the open system. The 1/2” hose maintains the 1/2” opening from the fitting. 1/2 to 5/8 hose difference wouldn’t change any real cfm difference in a less than 1 psi system. Haven’t seen many numbers on this, general consensus is just, bigger is better.

Hope someone with better information can help me make some sense of it.

Sent from my iPhone using Tapatalk

 

[moparkxracer]

You’ll still have pressure in the system, even with the valves removed. As RPM climb so will the pressure. 1/2 inch hoses wouldn’t be able to keep up with the flow. Prob end up with front or rear main seal leaks.

 

[ZC-DMAX-LMM]

You’ll still have pressure in the system, even with the valves removed. As RPM climb so will the pressure. 1/2 inch hoses wouldn’t be able to keep up with the flow. Prob end up with front or rear main seal leaks.

What does the pressure increase to that it wouldnt be handled? Still would have the limiting factor of the 1/2” port, correct?


Sent from my iPhone using Tapatalk

 

[moparkxracer]

What does the pressure increase to that it wouldnt be handled? Still would have the limiting factor of the 1/2” port, correct?


Sent from my iPhone using Tapatalk

the stock setup is pulling a vac on the system. I’ve plumbed it back into the exhaust after the muffler to be able to pull a vac in the crank case. As far as what pressure it would increase to, there are too many variables to be abt to give a number on what it would be.. ring gap, fueling, compression ratio etc.

 

[ZC-DMAX-LMM]

the stock setup is pulling a vac on the system. I’ve plumbed it back into the exhaust after the muffler to be able to pull a vac in the crank case. As far as what pressure it would increase to, there are too many variables to be abt to give a number on what it would be.. ring gap, fueling, compression ratio etc.

I like the idea of running it to a Venturi on my downpipe instead of back to atmosphere.


Sent from my iPhone using Tapatalk

 

[juddski88]

You’ll still have pressure in the system, even with the valves removed. As RPM climb so will the pressure. 1/2 inch hoses wouldn’t be able to keep up with the flow. Prob end up with front or rear main seal leaks.

This is not true for every engine. My race engine, with 20w-50, forged pistons and loose tolerances and probably less than ideal Ra cylinder wall finish, I vented to atmosphere and it only smoked a bit when cold. At temp during full throttle runs, it did not show any signs of excessive flow or pressure.