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StevoD

PCV Delete

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Hey everybody,

 

Been trying to get y head around a LMT intake kit i got about 2 years ago today. end up talking to the founder of LMT who recommended i do a PCV delete. 

 

Just curious what all you Zedders have done for a PCV delete 

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Got a custom PCV delete fitting from Project Import in the US. Then hooked my PCV system up to a catch can with a breather filter so it vents to atmosphere. If you want me to take some pics I will mate so you can get the idea.

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The PCV system on the Z like many cars is in two stages, the first idle and low load consists of a hose from the drivers side cam cover to the plenum with a non-return valve, and since the VQ motor breathes quite a lot of oil vapor at idle and low load due to high intake vacuum, which results in oil pooling in the lower part of the plenum, this is the one to add a catch can to, but it must be a sealed unit  otherwise any air leaks will cause un metered air to be drawn into the engine and weaken the mixture, 

The second part is on the passenger side cam cover, which is the high load side and is not subject to high vacuum, and a hose runs from the cam cover to a point on the  plastic intake which is often removed when a pop-charger or different intake pipe is fitted, this is only under suction when there is enough velocity in the intake to put t under vacuum, so the pipe can just be reconnected to keep a mild vacuum on the crankcase if you want to utilise this, or run to an open catch can or even just air a filter to avoid minimal oil mist.

 

Edited to correct my **** up.:blush:

Edited by Tricky-Ricky
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7 hours ago, StevoD said:

Isn't the passenger side the side that goes to the intake pipe?

Yes it is, my mistake, i will go back and edit my previous post.

Edited by Tricky-Ricky

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10 minutes ago, Tricky-Ricky said:

No the passenger side cam cover part of the PCV  goes to the plenum via a one-way valve, and is the one that needs a catch can.

What about when boosted dose this differ ?

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14 minutes ago, nissanman312 said:

What about when boosted dose this differ ?

No, as the one-way valve will prevent any positive pressure going back into the crankcase, but it may be prudent to replace said valve just in case it's a bit weak, and obviously, the high load side breather needs blocking or relocating for the same reason otherwise you would be pressurising the crankcase.

Edited by Tricky-Ricky

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1 hour ago, Tricky-Ricky said:

No the passenger side cam cover part of the PCV  goes to the plenum via a one-way valve, and is the one that needs a catch can.

Other way round, drivers side cam cover goes to the plenum - passenger side goes to the intake post maf.

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7 hours ago, StevoD said:

Isn't the passenger side the side that goes to the intake pipe?

 

3 hours ago, davey_83 said:

Other way round, drivers side cam cover goes to the plenum - passenger side goes to the intake post maf.

My apologies fellas, not thinking straight, was thinking LHD which i was driving a couple of weeks ago, i will go back and amend my previous post so as not to confuse further.:blush:

  • Haha 1

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You always want the PCV system to be enclosed and not vented to atmosphere as said, you want the vacuum to help draw out the waste oil vapour and reduce crankcase pressure. 

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I’m now about to fit a enclosed oil catch can & im turbo boosted.

 

currently my set up is pcv drilled out & vented to atmosphere with a filter. Then front plenum pipe blocked off. 

 

Rear breather plugged into oil catch can & tube from oil catch can to in front turbo intake to pull slight vacuum.

 

This or a better way to run the system ? 

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13 minutes ago, .:Bullen:. said:

I’m now about to fit a enclosed oil catch can & im turbo boosted.

 

currently my set up is pcv drilled out & vented to atmosphere with a filter. Then front plenum pipe blocked off. 

 

Rear breather plugged into oil catch can & tube from oil catch can to in front turbo intake to pull slight vacuum.

 

This or a better way to run the system ? 

That's perfect. Pretty much the same setup I'm running but I don't have the pipe to the intake anymore it's just vented to atmosphere. You don't need a slight vacuum with the pcv valve drilled out as any positive pressure in the crankcase will vent on its own as the pressure outside will be less than the crankcase

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Actually it is beneficial to keep a vacuum from  the  intake whether N/A or bosted, as it helps ring seal and helps prevent oil seal weep, the PVC system is no solely an emissions tool as most seem to believe, some engine types do  produce some small amount of positive pressure due to the receptive movement, so expelling this and creating a small amount of vacuum on those that don't is a good thing.

 

Eliminating the oil mist with a baffeled can is good but keeping the lot attached to a vacumsource is also good, nothing wrong with eliminating the low side of the PCV especially when going boosted, allthough not nessacery, but at least keep one side subject to vacume.

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Does the tube on the intake side have to be on the intake or can it just breathe from anywhere? Can't get my head round it. Trying to run the big fat tube to the air filter is causing problems. 

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10 hours ago, Kieran O'Quick said:

Does the tube on the intake side have to be on the intake or can it just breathe from anywhere? Can't get my head round it. Trying to run the big fat tube to the air filter is causing problems. 

I would advise having a vacuum source on the full throttle/high load side simply because it aids ring seal at high load, but its not going to do any harm if you vent to atmosphere, preferably by way of a catch can, but some use just a filter, however, I would advise caution doing this as you may fall foul of the new MOT laws that state any oil leaks/weeps will be an instant failure.

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