1. At idle, the PCV valve is closed and not pulling crankcase pressure (this is ok since there is no crankcase pressure at idle anyways) so at idle the PCV system is not "functional."

2. At WOT, the PCV system does not have enough vacuum to be an effective source for crankcase evacuation. WOT is when it is needed most. To me, this means the PCV system is not the most efficient system to rid the crankcase of high pressure.

3. The PCV system is only open AND providing a sufficient vacuum source at part throttle. The nice part is that this is where most people spend most of their time but it also means that this is when the most oil is sucked through the obviously flawed system.

I am not concerned about oil consumption through the PCV system, per say. My concern is that I do not want oil and burnt gasses as part of my combustion process. It is not efficient for my goals of more HP (and even good mileage).

I do not want to reinvent the wheel but there has got to be a better solution. Based on the above, we need a way to evacuate the crankcase with increasing efficiency the further we get from idle and the closer we get to WOT without pulling garbage into the combustion process.

Can someone tell me what is wrong with a setup that uses the exhaust system to evacuate the crankcase? A system that uses the flow of the exhaust to pull gasses out gets more effiecient with more throttle (flow). A one way check valve prevents backwards flow of exhaust gas into the crankcase. The fact that this system will not do anything at idle/very low RPM seems irrelevant to me because neither does the stock PCV setup.

You could run this and completely delete/cap off the intake/valley cover/TB/valve cover, etc and close your intake to everything except fresh, filtered air and do what is appropriate with the byproducts of combustion and expel them out the exhaust.

The system I am referring to is this or like this:
http://store.summitracing.com/partde...5&autoview=sku

Now, this would obviously not be emissions legal, but neither is deleting your cats, which plenty of you/us do. In fact, you probably wouldn't want cats with this setup anyways. This is not for greenies.

What do you think?

 

Those will only work on a car with open headers.
There will always be pressure in a muffled system.
Otherwise it would be a great idea.

 

I know these work. I don't know any reason why they wouldn't help in this application. If you decide to do it, do a write up on it.

 

There is still flow through the exhaust and that is what matters. The check valve won't allow pressure to run back up the line. I have read many accounts of people with other cars running this on the street....

I don't build Vettes like you do but I do run this on my two Super Stock cars (open headers, of course, lol) but I am not sure how a 1 7/8 headers, catless exhaust is going to be a problem. Stock exhaust, sure, I agree.

The next issue is what valve covers do I use that work on the LSx and have a breather hole on both sides?

 

The PCV valve isn't closed at idle. It just reduces the orifice size when there's high manifold vacuum (idle) to keep flow from increasing.

At wide open throttle, crankcase venting will rely on minor crankcase pressure, but it's not enough to worry about with a stock engine. What percent of the time can you spend at wide open throttle anyway?

True, there's some intake charge dilution with blowby, but I've never seen anyone show a significant power increase by getting rid of it.

You could use your electric air pump to purge the crankcase.......I don't know how long it will last though.

 

What if you turn the PCV valve backwards so there is not spring resistance holding the valve partially open and let the idle vacuum suck it closed completely (backwards)? There would be no oil flow through under high vacuum and when the vacuum decreased (upon throttle application) the check in the valve would rest against the spring in the opposite direction and be partially open instead of completely closed thereby allowing some flow through the system instead of dropping closed like stock? Combined with a valve cover breather (and capped off fresh air line) what would happen?

 

Ok, after thinking about this more I think I have narrowed my thoughts to two:

1) Keep factory system with catch can and analyze different PCV valves for size, spring stiffness, mounting position

2) Run the valley nipple to the PCV valve to the catch can to the exhaust evac (instead of the intake manifold) and retain the factory style fresh air line but possible move it from valve cover to filler neck.

Which road do you think makes more sense to pursue?