I did the same thing with the same thought process, so hopefully it's the right thing to do.

Thank you for all that brought this topic up. I asked my local speed shop mechanic about it and he recommended this concept to me. One quick use of the Search button and I found this. $20 and 20 minutes later, and I was all set up! No problems so far with whistling, stalling, or otherwise. I'm a happy camper.

 

I wanted to give every one an update. I had not removed any accumulated in in about 1500 miles. I noticed that as more oil accumulated, the *rate* at which it accumulated decreased. After the cannister became roughly 1/3rd full, I could no longer visibly see any change over time. I also noticed in the past two weeks that my pinging returned, just as bad as it had been before.

So yesterday I removed the oil, and let the cannister drip-dry. I drove the car a few miles yesterday and a few more today, and the pinging is almost completely gone, again. It still crops up once in a while, but it has been reduced by at least 80 to 90 per cent.

So guys, don't wait for this thing to fill up. I suggest cleaning it every few hundred miles. Not a big deal, certainly easier than say... vacuuming your floormats.

 

Trey, just a quick follow up. After my initial times where the car seemed to lose power momentarily upon firm upshifts into high revs while in Manual Mode, the car seems to still exhibit symptoms like this here and there...not consistent though which is odd and frustrating...It is definitely catching a lot of oil, but I just feel like something is off...could it be the lenght of hose we are using, IE, are they too long w/too many bends which may cause some kind of kink under WOT???

 

Does the hose appear to have retained its structure so far? These symptoms really seem like a collapsing hose issue, but you're running the same hose as me, Cheryl, and my friend in his SRT4. The hose is actually all off the same spindle. None of us has had the hose collapse, at all.

If you're not worried about emissions for a few days, disconnect the hose from the PCV vavle and let it expel to the atmosphere. If you're still having hesitation, then I don't know what it is. If not, then I would suggest chaning out the hose.

 

Trey,

I think it's the hose...it's so long and has those bends in it and when the car is hot and idling I can feel how soft the hose feels...especially at the bends...and I notice cold...if I squeeze the two hoses the OEM one seems stronger...

I just got back from a 400 mi round trip and the catc can is 3/4 full...that on top of 2-300 miles of driving b/f the trip...so it definitely works...I am just aftraid of the current set up.

So...What about those 90 degree fittings I saw in one post? Wouldn't those allow a much shorter hose with a straight shot to and from the PCV Valve and the origin point where the OEM hose is connected now?

 

Boss, interesting how yours got so full. I drove 1500 miles in one week and went to Motor Sport Ranch and TMS to race. Mine never got more than 1/2 full.

 

I just did this couple days ago before my trip and for every ~400-500 miles, it's about 1/3 full.

 

the rate of this thing catching oil decreases exponentailly as it fills up

mine never gets more than 1/4...

 

Yeah, this is what it looked like b/f I emptied it out. I talked to Trey and he suggested I shorten the hose a few inches, but I think I need to get the T-Adapters to do that.

My feelings, and this could be ignorance of this whole thing, is that with the longer hose it's trapping more oil, but also hurting engine power due to crimps and or bends that weaken under heat and load...

 

well, IMHO, since our makeshift oil catch can does not really have an "efficient" baffle, the condesation of the oil ("catching") depends really on the temperature difference between the oil in the hose and the catch can.

***
Moreover, the PCV system indeed has two connections, one being from the valve-cover to the lower intake, and the other one from the valve-cover to the intake tube. According to my normal knowledge:

1) During Idling and low throttle, the PCV utilizes the vacuum from the engine to pull the pass-by gas from the valve cover into the lower intake (and the PCV control valve is fully OPEN at this point)

2) During high throttle or high engine load, the tremendous amount of pressure in the valve-cover generated by the increase volume of the "blow-by" gas will now force the PCV valve to a CLOSE position, and the "blow-by" gas in the valve cover would be forced to go towards the intake tube (also known as Z/G tube)....

In a nutshell, the more oil you catch with this setup, it means that you drive alot of highway (under low throttle...) or you idle alot.. That's why you will also see people talk about DUAL catch can, which is designed in an attempt to catch the blow-by gas under BOTH idle/light and heavy throttle applications


***
Since my setup use very short hoses, I believe that's the major reason why my catch can does not catch any oil above the 1/3 level.

If you have long hoses and has successfully placed the oil catch can away from the engine heat (relatively), you should catch alot more oil.

Yet, concerning power loss, I wouldn't worry about it, since it is all about the volume of "pass-by" gas in the valve-cover being forced out into the lower intake by the PCV system.. Thus, provided that there is no leakage and the hose does NOT collapse, longer hose should not be a problem.


Sidenote: I would try to get longer hose and re-route the catch can to somewhere that has a higher temperature difference (lower).

 

Hey, thanks for all of that...very good information and much appreciated.

When I was at the Drag Strip the other night I ran a 14.4 @ 100.22 and I could have sworn there were some hesitations going on...so I took the catch can out, went back to stock, and ran a 14.2 at 100.82, and then followed that up with two more 14.3s hot lapped at 100.4 and 100.2 so I don't know, but my feeling was that right where the two connections go in and out of the catch can there was a hissing going on...and I still feel that the hose does not like the bends, IE, it collaspes in on itself...so I believe Trey is sending me some 90 Deg fittings to try.

As for my driving...you got it pegged...I am in Sales so on the highway a lot at lower rpms and then in traffic at idle a lot too. So that makes sense to me!

 

Actually an engine generates absolutely no vacuum under WOT throttle. The PCV valve closes because there is no vacuum. Vacuum at idle should be anywhere from 19-21 hg. Under part-throttle load, it might rise to as high as 24-26 hg. Under full throttle, the vacuum will drop to 0 hg.

 

Would I actually need one of these if I have taken off my plenum and found hardly any oil accumulation? I would think no. But I do experience 1-2 qts of consumption inbetween oil changes.

 

This is true but only to a point. AT WOT, vacuum will drop to 0 and then begin to increase as the RPMs increase and the sudden difference in supply and demand becomes equal.

This is an interesting thread. How old is it? I'm a new G owner and will probably do this mod, as I have found an amount of oil in my lower collector while installing and MREV that I found to be a bit much.

 

All of the VQ engines we've torn down have oil in the lower plenum. All of the catch cans we've installed on VQ engines catch oil. Of course a few special people have G35s with special engines that don't have oil in their plenums.