Crankcase Breather / oil catch tank

[Chris Y]

Jolly good. There are lots of other one-way valves on the market too. My point was that you could fairly easily connect something to the exhaust, rather than the inlet.

[trikesrule]

ian-w Have you ever pulled the dipstick out of a hot heavily worn engine? They puff away like mad. Which means to me that with each revolution the blowby exiting the crankcase area is caused by the pistons coming back down the bore. Don't have to recycle the extracted vacuum back into the manifold. We vent to the atmosphere. And as far as pulling out large amounts of oil that - just dosen't happen with a healthy engine........trikes

[ian_w]

All modern engines are designed to pull a very slight depression ( less than 1kPa ) in the crankcase - this is to limit HC and CO emissions to the atmosphere. Its done by using a PCV valve connected to the inlet and also a pipe from either the crankcase or cam cover to the airbox. I'm not really sure what the KrankVent system achieves beyond this.

How much vacuum do you expect to get from the system ( or the exhaust pulse ones )? How much power do you think this will give? Sure, all engines have a certain amount of blowby but is it really a big problem?

I guess I'm coming from the dry sump end of the scale where you can get pressures down to 30kPa absolute ( 70kPa vacuum ), which gives perhaps a 1-2% performance improvement. I just cant see how generating a tiny crankcase vacuum with any of these 'add-on' devices is really worth the effort / money compared to a properly engineered production breather system or even just a plain pipe and a catch bottle.

[Al Weyman]

How much vacuum do you expect to get from the system ( or the exhaust pulse ones )?

A lot more than you would ever imagine I tell you, you can buy the fluted tubes to weld into the manifolds and the one way valves and rocker cover oil seperators from Moroso, I was amazed at the amount of pressure they pull even at tickover.