| Just thought some of you "Backyard Engineers" might want to see a recent modification I've done to the "PCV" system on my very built Z32. Of course it's a very opinionated topic, but here is something totally different - and is probably unheard of for most of you even! As far as I know, it definitely hasn't been done with a VG30 yet... It is mostly a racing related application, however, in my opinion, is a no-compromise improvement to a very much left-out part of extreme VG30 builds. However, I will leave the rest to your discretion! *Disclaimer*: I am fully aware of any inherent risks a mod like this entails. And by no means intend any of you to do something like this to your vehicle(s). This is purely for curiosities sake, and any associated mod you perform is at your discretion - this is the internet after all!
*The Details* (briefly)
Ok, so if you search your ass off on here now and then like I have, you'll have found there are a lot of different ways to deal with positive crankcase pressure (IE: blow-by gases), via venting (known as PCV - Positive Crankcase Ventalation). Weather it be the stock system, the famed and effective re-route, or the more recently prevalent and simple vent-to-atmosphere (VTA). My ultimate goal with the engine in my Z, is system refinement/updating with no compromises - Ideally, I want as much vacuum in the crankcase, to not only remove blow-by gas quickly, but to improve ring seal (power and reliability), more readily prevent any fluid leakage, and decrease windage as a side bonus, as you will see below All have their pros and cons: - Stock/reroute 1) You are only pulling vaccum in the crankcase under 'sub-boost' conditions, before the check valves do their job and crankcase gas leaves the front breathers into the turbo inlets.
2) The gases produce an oily film in the intake tract/plenum, and excessive amounts can lead to a slight decrease in the detonation threshold (reduced octane rating basically). This can happen to a degree EVEN WITH A CATCH CAN (and they are a pain in the ass at that! - biased, sorry)
3) Basically a sub-optimal system madefor meeting emissions regulations. It does it's job fine though. if you like it, don't mess with it! - Atmospheric 1) Any excess pressure in the crankcase abides by the laws of physics, it will attempt to neutralize itself with the outside air via the easiest route possible.
2) The crankcase will naturally never see any vaccum, and a poorly vented system can see pressure, which, in excessive cases, can lead to leaks, dip-stick popout, etc.
3) Crankcase will never see any vacuum/negative pressure. Which is less than ideal. - Exhaust Venturi Evacuation 1) Crankcase vacuum is created via negative voids in exhaust pulses. Positive waves are filtered out via check valves.
2) A constant vacuum can be achieved, escalating until maximum flow is achieved (Some cases up to -10" WC!)
3) No side-effects, all gas goes in exhaust, exits/is burned out the tailpipes.
Now that you know a bit about those methods (for those of you that don't, perhaps research here: YES it's a Honda thread but it is very informative to help you understand! ). Finally, here is what I did.
It works off of the Bernoulli principle - a venturi effect over a surface where a medium flows over an area where a raised section creates a low-pressure area in which vacuum is created via suction. (a very simple example would be a plane wing!)
This is the basis of my system. After the wideband bungs in both testpipes, yet, as close to the downpipes as possible:
The exhaust gases flow over the slashcut tube, negative pressure waves pull vacuum through the tube. The thing is, you MUST have check-valves, due to the positive pressure waves and/or any chance of backfiring conditions. I used moroso metal check-valves, meant for drag racing/circle track evac systems. Along with my Vibrant SS E-vac Kit, two of each, one for each bank!
Anyways, Here are the pictures of my setup. Ran 5/8" Hose from my front breather tubes, plugged PCV valve ports in the plenum and valve cover, since I was VTA (vent to atmosphere) previously. Thought some of you might learn a bit/ find this at least slightly interesting. It has worked well for about 500km's of mixed driving thus far. I was going to also implement over-pressure atmospheric check-valves as well, but I found the exhaust pressure hasn't ever been positive to warrant ANY pressurization of the crankcase. And from what my crappy vacuum/pressure gauage can tell. I am pulling a few Inches H20 at idle/free rev! Plus I notice a lot more vapor coating my clear PVC tubing now as well (luckily not sucking oil out - which would mean too much vacuum! hehe).
^Check Valves, 5/8"/-10 AN Adapters x 1/2" Mip to adapt to Vibrant E-vac Kit (Didn't like the moroso reeds/venturis, and didn't like the cost of Vibrant check-valves!!!). The 90* St. Elbows were used for clearance. No, they don't effect vacuum generated in any way. Only way I could tuck them up out of the way of any potential road contact. 
Slash-Cut Bung installed, being sure to clock the venturi the right way! 
Installed View - NOTE: I normally run dual WBO2's. Dumbass here did one in on a needlessly fast speed bump, whoops... Other than that, I really baby my Z!
In conclusion. This mod really is just another thing you'd never know existed/was special by looking at the engine normally... One of many actually! However, I am happy in the end knowing it makes an impact in the overall functionality of the engine, and in my situation - for the better!
The best part... I probably gained some power due to better piston ring seal, less windage, and no Blow-by gases in my intake! If you have any questions, or want to tell me how much an idiot I've been (doubtful :] ), I will be happy to answer!
Thanks for reading,
Nick
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Version 3.01 
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VG Exhaust Crankcase Evacuation Setup! My Z Experiment... - 
