Anyone else running no pcv?

[MyBeatGSX]

I was a little disturbed when I took it for the first drive with no PCV (RRE catch can hooked up taboo style). Whatever the catch can is venting it smells like pure gas. With the heater on fresh air it even gets sucked inside and blown in my face.

Is it normal to have that much blow by at idle? Does anyone else have enough to smell inside the car? Its cold enough outside that I can actually see the smoke slowly rising from the breather while my car is parked. The blow by can't be that bad. Because I had that catch can hooked up to just the breather for like 3 months and it didn't collect a drop of oil.

Aside from that, the car runs better...

 

[v8s_are_slow]

I've had mine setup the way RRE did and took out the pcv valve. I think it's giving me some problems and wanna maybe turn it back to stock....somewhat. Think I'll go and get me a pcv valve tomorrow and put back in. But what I'm wondering is if it'd hurt to have the other line that originally goes to the intake pipe and route it to the intake manifold instead. Essentially, having both the pcv line AND the other line both just going to the SMIM I have. Any opinions on that? I ask because I don't have a nipple in my intake pipe so of course can't run the other line there. Will that one effect a/f ratios as well or just the pcv valve side?

When I decelerate or at idle sometimes, my car is smoking pretty good and smells like oil to me. It's a new motor and I've been wondering if this could be the issue. Thanks!

P.S. Thanks for that article Oldman, it was a good read for me.

 

[oldman]

I too didn't have a fitting on my Dejon pipe but it took me 10 mins to drill and tap for a 1/4 npt to 1/4" fitting. There are several problems running both to the manifold.

1. Lack of fresh air source leading to lack of ventilation.

2. High vacuum in the crankcase leading to higher oil comsumption and possible seal damages.

3. What do you think will happen to the breather when you're under boost?

 

[v8s_are_slow]

Well I'm running speed density and so running it to the intake pipe is about the same as running it to the catchcan right? Albeit, a lil less vacuum than the intake pipe would provide. Wouldn't I be okay just putting the pcv back in and keeping the other to the catchcan? The pcv is the one that matters isn't it? Or would both of them effect the a/f ratio, blowby, etc.?

 

[oldman]

Well I'm running speed density and so running it to the intake pipe is about the same as running it to the catchcan right? Albeit, a lil less vacuum than the intake pipe would provide. Wouldn't I be okay just putting the pcv back in and keeping the other to the catchcan? The pcv is the one that matters isn't it? Or would both of them effect the a/f ratio, blowby, etc.?

With tuning capacity, you should be able to compensate for it easily.

 

[staticbrainwash]

Old man, How hard was it to drill and tap your dejon intake pipe? Mine also doesn't have a fitting for the VC line so i'd like to remedy this.

Were you able to get enough threads into the pipe to make the fitting work or will a bung need to be welded on to be safe?

 

[v8s_are_slow]

I can tell ya now that I wouldn't think the pipe would have enough thickness to tap it and have reliable strength. One thing you could maybe do is take a metal valve stem (the kind that has a nut to hold it in place), drill a hole and put this on without the valve core. Sure you could get a vacuum hose wide enough for it. Would think that'd work just fine.

 

[oldman]

Old man, How hard was it to drill and tap your dejon intake pipe? Mine also doesn't have a fitting for the VC line so i'd like to remedy this.

Were you able to get enough threads into the pipe to make the fitting work or will a bung need to be welded on to be safe?

Not that hard at all but V8 is right, most intake pipes, unless it's casted like the FP 4"er, will not have enough meat. You can either weld a bung on it or do what I did, JB weld/RTV the fitting thread but make sure you don't over torgue it. You should be fine with just JB welds because the only pressure this fitting will ever see is some vacuum when turbo is spooling.

 

[staticbrainwash]

Cool, thank you very much.

 

[tsunari]

Good thread . . . valuable info . . . how about someone running with a GM MAF in blow-thru setup?

I'm guessing if you're at that point, you should be able to tune out the little bit of un-metered air while in vacuum and just set it up like stock?

 

[oldman]

Good thread . . . valuable info . . . how about someone running with a GM MAF in blow-thru setup?

I'm guessing if you're at that point, you should be able to tune out the little bit of un-metered air while in vacuum and just set it up like stock?

If you're running blow through, you can vent the breather but definitely keep your pcv stock. The inline catch can on the way to the intake pipe is working out so well for me that even if I go blow through, I will probably still recirculate to keep my engine bay clean.

 

[v8s_are_slow]

I have a question as to how the pcv valve messes with the afr's. I ask because I'd think that whatever the wideband see's would be a true afr cause it's only reading what's in the exhaust. I wouldn't think that the metered air, etc. would be a factor cause any fuel and air that's burned still doesn't get read until it hits the wideband downstream.

I've been running in the 12's as far as my afr's goes with no knock at around 23 psi on pump, so kinda wondering if it's the pcv valve not being installed or if it's my Maftpro, or if what I'm seeing are true readings. I recently found out that if I have the most recent version of Maftpro but the .ads and .xdf files for the laptop are older versions, then the readings will be off. Not sure if that would include my wideband readings as well.

Anyway, my motor is out right now so haven't been able to test out the car with the pcv back in yet. But just pondering ideas about my afr readings though. Thanks!

 

[MyBeatGSX]

You are correct. Your AFR is whatever the wideband says it is. Connecting or disconnecting the PCV will not make your wideband inaccurate.

However, the point Oldman was making is that the stock setup is a closed system. The air used to circulate through the crankcase was sucked in post MAF and so was already accounted for. So when it gets sucked through the PCV and into the intake, the ECU was already expecting it and will have added appropriate fuel.

But if you run an open breather filter, the air getting sucked through the PCV was not read by the MAF. That means the ECU didn't add fuel to account for the extra air. This makes you run lean. Just like disconnecting a vacuum line on the TB.

It won't change the accuracy of your AFR readings. But it will change your AFR, and you'll see this on the wideband (in theory anyway).

 

[Drifter27_04]

You are correct. Your AFR is whatever the wideband says it is. Connecting or disconnecting the PCV will not make your wideband inaccurate.

However, the point Oldman was making is that the stock setup is a closed system. The air used to circulate through the crankcase was sucked in post MAF and so was already accounted for. So when it gets sucked through the PCV and into the intake, the ECU was already expecting it and will have added appropriate fuel.

But if you run an open breather filter, the air getting sucked through the PCV was not read by the MAF. That means the ECU didn't add fuel to account for the extra air. This makes you run lean. Just like disconnecting a vacuum line on the TB.

It won't change the accuracy of your AFR readings. But it will change your AFR, and you'll see this on the wideband (in theory anyway).

What if you are running the GM MAS with a blow thru setup how would that affect things? Just a curious question since it does sound like you are talking about the stock setup w/ the MAF before turbo. Thanks

Sorry for this post as I did not look up far enough...........

 

[speedmaster747]

Final setup. I agree with no pcv valvle. if you inspect your car and pass then im near 100% sure that is not heavy modifyed. If is the case leave it stock.

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Hehe, you welcome,

Good info. I will update my setup!

 

[t0ny007]

The PCV effectively and simplistically takes out unwanted, harmful blow-by in your crank case and removes it via vacuum in the intake manifold. This feature is not in function under WOT. In fact once the intake manifold reaches 1psi, it is theoretically closed and not in use. Taking out the PCV system seems pretty dumb to me.
http://dsmtuners.com/forums/showthread.php?t=224901

 

[WillRaceForBeer]

What if you are running the GM MAS with a blow thru setup how would that affect things? Just a curious question since it does sound like you are talking about the stock setup w/ the MAF before turbo. Thanks

I'm running a GM MAS and have wondered about this too... for simplicity I simply have the line that "would" go to the intake venteD... I know, not the best way method, but keeps any blowby out of my inake and I/C pipes.

So the delima with the blow through setup:

Ultimately you want all air entering the engine to be metered at all times, none lost, none gained.

1.) If you run a PCV and vent the other vacuum line like me... you suck in air at idle/cruise, and blow some amount air out at WOT, depending on the condition of your engine you may blow out a considerable amount. Either way this is bad for LTFT's, and bad for consitancy, and maybe even bad for seals, and the motor.

2.) If you run a PCV and run the other vacuum line to the intake, then you've now made the problem worse! although the air sucked in durring idle may be reduced because of two negative draws, at WOT any air being blown into the intake is effectively getting counted twice! Although you could argue it's taking the place of other air that "would be" counted... At the same time your blowing other shit into the intake with that air, so IMHO this is the worst setup.

3.) An option I will be exploring is having the pcv valve go to a catch can, the other vaccum line to a catch can, and the rather than venting the catch can, run it to the exhaust.... If you have a line going into the exhaust at an angle, the exhaust creates a ventury(sp) effect, and creates a vacuum pressure. Rather than sucking air in at idle, this should somewhat minimize that effect, yet at WOT should create considerable vacuum to put pressure under the rings and create a better seal, at the same time drawing out any blowby and "burning" it off.... This way your GF is happy, and the guy behind you's GF is the one getting pissed... I learned about this technique from some domestic guys, not sure how it will work in a DSM application, but i'm going to do some research, see what other DSMer's have tried similar, and let everyone know what I find out.

 

[v8s_are_slow]

Just curious but for your 3rd option, did you think about the fact that under vacuum, you'd be sucking in nice hot burned exhaust back into the motor???

 

[compression]

i just left the pcv in the valve cover with no vaccum lines to it, capped of the vaccum source of course, and hooked the other breather to my stock intake tube. never had any problems