FredR

Tuomo,

Did actually consider something along those lines during the first Pro vent incarnation. One possibility was to drill a hole through both sides and stick a tube bridging both sides with the top quadrant cut out to vent gas but not collect any free flowing oil sloshing around in there.

In the end it was the path of least resistance as John was able to supply a nozzle, a hose to carry the oil away and - wait for it- a bung to shove down the nozzle to permit oil fill and avoid pouring the stuff straight into the Pro vent- you just have to remember to remove it after filling assuming you can find it in the first place!

The packaging is neater this way but as you say there may be a little tendency to collect oil when braking in real anger if the baffle does not take it all out as we suspect it does at the moment. Similarly the packaging may be a bit more tricky from the side- doubtless doable but not so sure how it would look.

Rgds

Fred

ptuomov

A quick update on the boosted motor crankcase breather system in the below video at the 12 minute mark:

ptuomov

j.kenzie@sbcglobal.net

Is the jet pump an off the shelf item?
Thanks,
Dave

ptuomov

I think the 928 brake boost venturi jet pump could be used. One would also need a t-fitting, one check valve (as the other is built into the venturi jet pump), and two calibrated metering orifices. The main uncertainty about this reuse of a component would be whether the 928 venturi jet pump can handle a little bit of oil.

V2Rocket

using pressure from intercooler to make a jet that draws in valve cover vapors to eject to the manifold?

but why check valve to compressor inlet? wouldn't it make sense to put the check valve on the plenum side, so that when plenum is in boost the vapor flow goes to the compressor inlet?

ptuomov

The main operating modes:

Part throttle, no boost. Compressor inlet at atmospheric pressure, intercooler bottom tank at atmospheric pressure, intake manifold at a vacuum. Intake manifold vacuum pulls air from the intercooler bottom tank, and the venturi jet pump pulls a vacuum in the crankcase. The check valve prevents air from being pulled from the compressor inlet.

Full throttle, no boost. The check valve in the compressor inlet has a cracking pressure of something like 5 psi. This means that the path to compressor inlet will remain closed. There's some limited flow from intercooler end tank to intake manifold, but the system is mostly inactive.

Full throttle, full boost. The intake manifold and intercooler bottom tank have similar pressure, with the intake manifold slightly lower because of piping flow restriction. There's a big pressure differential between the compressor inlet and intercooler end tank, and that opens the check valve. Boost is being wasted back to the compressor inlet, but that's ok as above 5psi there's room to waste some. The benefit is a strong crankcase vacuum.

ptuomov

If you'd really want to simplify this venturi jet pump idea for a supercharged or turbo car, simply plumbing a break booster venturi jet pump from compressor inlet to compressor outlet and connecting the vacuum port of the venturi jet pump to the crankcase breather port would work. One would just have to play with a restrictor in the compressor outlet port to calibrate the vacuum and the flow. This would bleed off a little bit of boost but pull a nice vacuum into the crankcase at high rpms and load.

ptuomov

V2Rocket

that one i like.
think there's a need for a check valve to valve cover despite having the venturi?

ptuomov

ptuomov

ptuomov

John Kuhn has now been able to test this breather configuration in my car for a while. There are some recent tests of some significance.

The main new one is that with the newly built high-rpm short block, the breather system doesn’t eject oil at 8000 rpm. The termination catch cans are dry after all the shakedowns and dyno experiments.

Recall that my engine has adapted stock breather tubes in all can cover ports, which indicates to me that there’s no excessive oil accumulation in the heads at high rpms either for my engine.

There are some more dyno tuning and experiments to be done, after which the car needs to be subjected for street driving g-forced for an extended period of time to further test the breather system.

Alan

Tuomo,
Did you ever get baseline/current blowby ratios over RPM & load for your cars from your evaluations with the blowby meter? Interested to know the approx max percentages you saw and what gave you any improvements (if any)

Alan