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yea the price is pretty steep for a slightly better functioning check valve. i feel like you can accomplish the same function with only a catch can without the use of any valves, routing a return line from the catch can back to the intake arm so in essence its a closed loop system. have the pcv port line (with stock pcv removed) and breather port line going to the catch can, then a single line from the baffled catch can back to the intake arm.
I mean it probably wont work as precisely as with the fancy valves but wont this design be pretty close? When throttle is open, it'll suck all the blow by and pressure out the crank case and when the throttle is closed all the pressurized gases will exit through the intake arm and blow off valve...right?
Correction! My original post said, "I'm coming up empty finding that explanation and/or how they ought to be configured for FI. Anyone have that documentation and/or photos (or links) that would clearly explain them?"
I had/have no intention of getting into a debate on this issue. Everyone's entitled to their own opinion (informed or otherwise), and I'm not going to try to change anyone else's mind. I thoroughly researched this issue many years ago as well as before posting for answers to the questions I posed, and (1) I know what (if not exactly how) I want to do it, and (2) I wanted to refresh my mind on the technology behind the Krankvents. And my recollection is that the ideal in the crankcase is to have a slight vacuum.
BTW, quite a few on S2KI seem to have found an alternative by replacing the relatively weak S2000's OEM PCV valve by a stronger one from the FI Supra.
Oh and BTW re your diagram, Mijae007, hi-boost in your pipe leading to the IM will pressurize the catch can (which I'm guessing you'd not have vented), and that hi-pressure would then be introduced into the engine via the other 2 lines. Might be worth a re-think!
Yesterday a Spyderchat compatriot who was doing R&D work along with me in Rotrexing our MR2 Spyders back some 8 years ago sent me this drawing. We had consulted with the maker of the Krankvents and ended up with this configuration. My setup was essentially the same.
As a point of clarification, those two Krankvents are "pointed" away from the engine (the smaller (and stronger) of the two in the PCV hose), i.e., excessive pressure within the engine can escape out through them, but no air can enter back through those check valves and into the engine. This results is the only air entering the crankcase is the result of blowby past the piston rings and (ideally) a slight vacuum in the crankcase. This (theoretically) results in the piston rings seating better on the ring lands, and based upon testimony posted by many on various Forums who have installed the Krankvents, has resulted in dramatically reducing what had been excessive oil consumption.
Last edited by Coloradocurt; 01-23-2018 at 03:53 AM.
Ahh thanks for posting up that diagram, it clears up so much confusion. So the breather line goes to an "open" catch can and the pcv line goes to a "closed" can.
So ideally you need a dual catch can setup (one open, one closed). No wonder ive been running in circles trying to figure out how to properly setup my lines using one catch can. I like the idea of seating the rings with a properly functioning vacuum system.
One last question, for the pcv line return, does it matter if its placed before or after the throttle plate?
Ahh thanks for posting up that diagram, it clears up so much confusion. So the breather line goes to an "open" catch can and the pcv line goes to a "closed" can.
So ideally you need a dual catch can setup (one open, one closed). No wonder ive been running in circles trying to figure out how to properly setup my lines using one catch can. I like the idea of seating the rings with a properly functioning vacuum system.
One last question, for the pcv line return, does it matter if its placed before or after the throttle plate?
My system was set up almost identically, but didn't use a catch can on the PCV line - which routes into the IM (i.e., after the TB). He just wanted to ensure that he wasn't "inhaling" any oil fumes back into the engine's intake air. Similarly, the breather line could be run to the air cleaner (i.e., upstream of the supercharger) but again, those fumes would be going into the intake air (and since that MAF is of the hot-wire variety, getting oil vapor mist onto that hot-wire could mess up the ECU's reading of the amount of air going into the engine.
To get an idea of how meticulous and craftsmen-like work this guy does, here's a shot of the twin catch cans he did-
....................One last question, for the pcv line return, does it matter if its placed before or after the throttle plate?
It needs to be after the throttle plate so that when you have a closed (or only partially-open) throttle plate the IM is in vacuum mode and thus sucking air out thru the PCV/KV check valves.
01-22-2018, 01:02 PM
