Small Intake question

[mikewags]

I have seen L28's with a mini filter (like the K&N barrel filters) on the little flange on top of the Valve cover. I figure this is air intake as well right?

Is there any improvement in removing the hose that runs from the cold air intake to the top of the valve cover, and replacing it with one of those tiny filters? The only issue I see is that the air that will draw into through the top (valve cover) won't be from the cold air intake, but hot surrounding engine air.

Will this allow more of the air from the intake to just go straight to the manifold, or am I grasping at straws here trying to think up ways to gain 10 hp?

If you guys have no idea what I'm talking about, i'll scour around for a picture of the motor with it on.

Thanks!

[beandip]

The vent on the top of the valve cover is to relieve pressure built up from blow by past the piston rings. It is not a intake. The little filter is to stop oil particles form spraying mostly. You likely will smell fumes inside the cabin from the engine vented in this manner. Depending on the model year of your Z the engine is in a closed loop so all fumes are burned by the engine.

[WarrenZ]

Most likely you will see them fitted to cars with non standard air cleaners or SU's replaced by tripple carbs where both do not have a means to recycle the blow by.

Haven't noticed the any fuel smell yet.

Warren

[sblake01]

On the EFI cars, I'd leave the emission hoses setup the way they're supposed to be. You will get fumes from an open filter on your 75.

[doradox]

Actually the little vent should be working as an clean air intake into the engine. The PCV valve pulls fumes from the crankcase into the intake manifold to be burned and that vent supplies clean air to replace the fumes. Assuming, of course, that your engine doesn't have an over abundance of blow by. And the PCV valve is working.

Steve

[sblake01]

It's a bit more complex than that on the EFI cars.

[doradox]

It's a bit more complex than that on the EFI cars.

On page ET-11 of the 75 FSM, figure ET-26 shows exactly what I described.

Steve

[sblake01]

I'm talking beyond the function of the PCV. What I should have said it that the EFI setup uses this as well as other factors in determining the air/fuel ratio and when you remove the hose and replace it with an air filter, and you'd also have to plug where the other end of the hose was conected, you're changing that input.

[mikewags]

Ah, I was totally wrong. Ok, good to know. Thanks fellas.

[doradox]

I'm talking beyond the function of the PCV. What I should have said it that the EFI setup uses this as well as other factors in determining the air/fuel ratio and when you remove the hose and replace it with an air filter, and you'd also have to plug where the other end of the hose was conected, you're changing that input.

Yes, I see your point, having a vent (the little filter) to atmosphere would would allow PCV air to bypass the airflow meter. I was just pointing out that air should be going IN the filter and not OUT.

Steve