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Read the recent posts about crank venting issues as it relates to pressurizing the turbo and lowering performance. Here's a few stray additional thoughts. With my older CIS outfitted to work with a 16V engine, I still have the original air filter set-up where the crank vents into the filter box via a port which runs the gases directly into the intake flow just before it enters the air flow sensor plate. Because it enters through a downward vertical tube, most of the oil drops to the base of the filter box. When I change the filter (every 12 months) there's always a nice pool of oil in there. Oil does make it's way up through the sensor plate as well, as is seen whenever I take the intake piping apart. Because of your collective comments about how oil can sap an intercooler's efficiency, what to speak of lowering the octane charge, I'm gonna look into a way of trapping that oil before it makes it's way into the filter box.
But those crank gases might be useful as far as cooling the charge under cruse conditions like an EGR system. My understanding of the EGR system was a means to lower the combustion charge under select conditions, mostly while cruising, thus lowering HC emissions. HC is often the result of pre-ignition which can happen with any bit of carbon buildup within the combustion chamber. With my original 8VT engine (with lots of miles on it), and burning low octane fuel, I sometimes could hear ping while cruising at highway speeds. With the ignition advanced a few degrees (for that low end kick) the ping was especially noticable. I then installed a functional EGR system along the way and so long as the ignition wasn't advanced beyond a few degrees, the ping wasn't noticable. High octane fuel certainly helped as well.
So I'm wondering if there wouldn't be some use for those crank gases even in a high performance engine. That is, some sort of oil trapping and venting scheme so that it draws the gases (after the IC) while cruising to help lower the charge temp and avoid ping, but vents to open air under boost conditions. Some lil threeway doodad valve that opens under vacuum and closes under boost, just like the egr valve. Crazy? Pointless? Looking way too hard to find something to do? Get a girlfriend?
posted by 64.12.116...
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