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The mkiv Supra Owners Club

Catch can


Guest NathanMcbeath94

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Pretty simple.

 

If you are planning on using the stock outlets, then measure them and order rubber hose to size. Connect to catch can and go (make sure your catch can has suitably sized ports). Routing back from catch can to intake is optional.

 

However.

 

The stock pcv valve on the passengerside of the engine closes under boost (especially if you are single turbo), which doesn't really help with nicely distributed pressure release. Keep this in mind if you know your engine suffers from a lot of blow by pressure. For a stock TT, I doubt it will cause any realistic issues.

 

Ideally you want to weld in an AN adapter on in place of the stock PCV outlets in order to remove any possible pressure reliving restrictions for blow by gases.

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If you fit one its best to have a sealed unit and run a line back to the intake, to make the most of the engine vacum, make sure you use both the high load side and the idle/cruse, as this is the one that will produce the most oil mist.

 

The advantages are, if properly done, keeping oil from pooling on low spots of the intake runners which gets drawn in on the first large throttle opening, and you still get the benefit of the intake vacuum effect on the oil seals etc.

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Guest NathanMcbeath94
Pretty simple.

 

If you are planning on using the stock outlets, then measure them and order rubber hose to size. Connect to catch can and go (make sure your catch can has suitably sized ports). Routing back from catch can to intake is optional.

 

However.

 

The stock pcv valve on the passengerside of the engine closes under boost (especially if you are single turbo), which doesn't really help with nicely distributed pressure release. Keep this in mind if you know your engine suffers from a lot of blow by pressure. For a stock TT, I doubt it will cause any realistic issues.

 

Ideally you want to weld in an AN adapter on in place of the stock PCV outlets in order to remove any possible pressure reliving restrictions for blow by gases.

 

Thanks for the detailed response mate, that was my worry, I heard that the pvc can cause problems if you have a stock ecu.

 

 

 

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Just to clarify the PCV system refers to the whole system, and has nothing to do with the ECU, there seems to be some confusion here, the pcv (positive crankcase ventilation) consists of two parts, the idle/low throttle/cruse side which is covered by the right hand side cam cover which has the one way valve in that closes under boost to prevent crankcase pressurization, obviously a bad thing for gaskets/seals etc.

 

And the high load side which is in the other cam cover, and this goes directly to the turbo intake to use the vacuum to equalize and create a small vacuum which helps with ring and oil seal sealing.

 

If you just fit a catch can to one side and not the other then fit it to the low side 9penim side cam cover vent, and block the plenum where it connects, this may or may not help with the oil in the intake, but remember it has no vacuum if open to atmosphere.

 

As i said the best option is to T the two cam cover breathers together and run to a sealed catch can, and use the other can outlet plumbed back into the turbo intake, this will help with excess oil mist and retain the PCV effect.

Edited by Tricky-Ricky (see edit history)
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Just to clarify the PCV system refers to the whole system, and has nothing to do with the ECU, there seems to be some confusion here, the pcv (positive crankcase ventilation) consists of two parts, the idle/low throttle/cruse side which is covered by the right hand side cam cover which has the one way valve in that closes under boost to prevent crankcase pressurization, obviously a bad thing for gaskets/seals etc.

 

And the high load side which is in the other cam cover, and this goes directly to the turbo intake to use the vacuum to equalize and create a small vacuum which helps with ring and oil seal sealing.

 

If you just fit a catch can to one side and not the other then fit it to the low side and block the one way valve at the cam cover and plenum, this may or may not help with the oil in the intake, but remember it has no vacuum if open to atmosphere.

 

As i said the best option is to T the two cam cover breathers together and run to a sealed catch can, and use the other can outlet plumbed back into the turbo intake, this will help with excess oil mist and retain the PCV effect.

 

Never a good idea to block one side of the PCV system imo. Either connect it to the catch can system or leave it as it was stock.

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Never a good idea to block one side of the PCV system imo. Either connect it to the catch can system or leave it as it was stock.

 

I think you misunderstood, i was referring to those wishing to add a catch can in the simplest format, IE just to one side of the system, so i advised fitting to the low throttle side by blocking the plenum and using the cam cover that would have normally been connected to this as the source of the feed too the can, this way its not ideal but if they want to lave it vented to atmosphere its not a problem.

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I think you misunderstood, i was referring to those wishing to add a catch can in the simplest format, IE just to one side of the system, so i advised fitting to the low throttle side by blocking the plenum and using the cam cover that would have normally been connected to this as the source of the feed too the can, this way its not ideal but if they want to lave it vented to atmosphere its not a problem.

 

If you just fit a catch can to one side and not the other then fit it to the low side and block the one way valve at the cam cover and plenum, this may or may not help with the oil in the intake, but remember it has no vacuum if open to atmosphere.

 

Might want to edit your post then as what you wrote before is a contradiction to your last post.

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