Hi all just wondering what people have done for a PCV valve when turbo-ing their a series to get through engineering etc

modern factory turbo engines use an oil/vapor separator -- a catch can, with a check valve to prevent pressurizing the can. And another check valve to draw air through the air filter at higher speeds

PCV has two modes of operation:
1. Idle vacuum sucks a tiny bit of crankcase air through the Valve
2. non-idle airflow sucks crankcase air through air filter housing
The second is a problem with any engine that has excessive blowby such as a worn engine or a highly boosted engine. For excessive blowby a catch can is needed (or if the rings are worn, new rings are called for)

http://blog.modbargains.com/turbo-car-need-oil-catch-can/

http://stratifiedauto.com/blog/unders ... -upgrades-and-catch-cans/

Alternatively, some run a small vacuum pump to provide crankcase vacuum at all times. For example VW or Ford electric smog pump about $125. This allows using unmodified PCV system, just move PCV inlet from manifold to pump. Not sure if engineering will sign off on this

Thanks David yet again!

I was told Normally the pcv goes into the manifold, but can run the crank case pcv into the intake before the turbo on a turbo car as it sucks it back through the engine for emissions

So does that mean you can plumb both the crankcase pcv and rocker cover to the intake pipe before the turbo which also has your air filter on the end? I.e.




Sorry I'd love a diagram I'm more a visual learner

Quote:Yes, you can do that. I understand the reason engine manufacturers don't do that is because it exposes the turbo to blowby gases -- which are normally not a problem but with engine wear it becomes a problem and with large boost ditto. For 10psi boost and good rings it might be OK -- but since it's up to the Engineer, I'd check with your engineer before doing anything

BMW turbo uses a catch can/PCV system along with their typically complicated PCV design

Modern Ford turbo here in USA uses a vacuum pump and catch can

If I ran a 3 port catch can in that setup would it be better?

Or would there be a better way of routing it?

Here is a link to a pdf article on the Australian Rex Bunn developed breather system used for classic motorcycles but relevant to any engine especially high RPM engines, You can also search for and read the patent documents to gain a better understanding of engine breather systems and work out how to improve you own system.
http://www.britcycle.com/Products/Bun ... Bunn_Breather_Article.pdf