KodSol

is the hose from the intake to the top of the valve cover mandatory? i don't have one on my z6, i just have a small filter on the valve cover port and nothing going to the intake. Also, any other hoses that would need to be included in this?

Former User

Post pictures.

It's called the breather hose. It provides air to ventilate the crankcase for the PCV system. I see no benefit of the filter over drawing air from the intake, which is already filtered air.

dwkt

The idea of the filter is people don't want contaminated air going into their intake. so they block off the hose connection with a filter, now the only air coming in through your intake is fresh air.

Former User

But why ever modify the system at all? I don't see the point. The stock set up requires no extra filter, just the intake air filter.

And don't forget that the PCV air intake is required for proper idle control.

KodSol

gotcha..thanks much

apexi_rsx

im not too much for running that hose back into my intake nor the one coming from the black box because when the check valve fails u get oil gunk all over the inside of the intake manifold.

Former User

That's one reason that regular oil changes are so important.

andrew4g63

I totally agree with Ron on this one.
It was a great design at the factory so leave it alone and use the factory air filter/tube.

NotAJDMFanBoy

You block that off and use a filter to keep the oil from going into the intake. Oil reduces the effective octane of the fuel, and it dirties up the intake manifold, intake valves, leaves carbon deposits in the cylinders... They ran the tube to burn the oil up instead of letting it vent to the atmosphere. If you run a catch can and drain it into your oil change pan/jug/whatever, it will be fine. There will be condensation and oil and some unburnt hydrocarbons, but no different than regular used oil.

The PCV system can be eliminated. The whole box is removed and the hole was plugged on my motor. It's gone. No more. Idle is perfectly fine.

Former User

My guess is that you don't have a stock set up. For a stock system, just leave well enough alone. It does affect idle speed because the ECU expects air from the PCV system. For a stock system, the PCV system does not hurt performance when the engine is properly maintained and reduces toxic emissions from the crankcase.