Breather tank question

[_Shane_]

I have 10an fittings on my cam covers and i am making up a breather tank setup for my Supra

 

The question i have here is that some breather tanks that i see for sale have 4 and 6 ports on them.

 

Am i right in saying all i should be doing is running the lines from my cam covers to 2 of the fittings on a breather tank

 

Might sound like a stupid question but what are the additional ports on some breather tanks for ???

 

Cheers

[Mk4Gaz]

You ideally want a take off at the bottom, to drain the oil/condensation residue periodically, obviously a port at the top for a filter, or some people run a line back to the intake pipe

 

 

[berg]

Mines a Whifbitz that uses a line from each rocker cover then just a breather filter on the top

 

But running a line back to the filter pipe instead of a breather is something im thinking about doing as it blows alot of steamy vapour out when running

 

Mines been fitted exactly a year now and its still empty and doesnt register on the check tube

[Mike2JZ]

Speak with your tuner, see if he has any recommendations.

 

There are good arguments to say that you should have your catch can system attached to a vacuum source to help the flow of gases, whilst there are also good arguments to say that you don't want to PCV gases rerouted to your intake system in order to try and keep the flow of air to your cylinders as clean as possible.

[Tricky-Ricky]

Its more a case of keeping the oil vapor out of the intake, as it tends to pool in the low parts and get drawn in on mass at the first major throttle opening, especially on the std PCV setup, its not really a problem on a catch tanks setup with the tank plumbed back into the intake.

 

Actually with a healthy motor there is very little air movement, the motor produces no measurable positive or negative pressure contrary to what a lot of people used to think.

[Mike2JZ]

Its more a case of keeping the oil vapor out of the intake, as it tends to pool in the low parts and get drawn in on mass at the first major throttle opening, especially on the std PCV setup, its not really a problem on a catch tanks setup with the tank plumbed back into the intake.

 

Actually with a healthy motor there is very little air movement, the motor produces no measurable positive or negative pressure contrary to what a lot of people used to think.

 

Unless OP has had a fresh engine rebuild recently, chances are he is running on a 20 year+ bottom end and now wants to run a lot of boost through a big turbo in his upcoming tuning session. There will be an amount of blowby produced by the engine after being in service for that many years and now being asked to make triple the power. Do you really want these fumes to be recirculated into the intake system and contaminating your intake air?

 

Considering he is running on irish 95 octane, I would be taking every step possible to help the engine from knocking, like keeping your air supply as pure as possible. Every little helps in that sort of situation. Remember that routing the PCV gases back to the engine to be re burned is an exercise of reducing emissions, not optimizing power.

 

Oil fumes are still circulated back into the system with a catch can routed back to the intake. The catch can only catches some of it, it does not eliminate it. Keeping the intake clean is a nice side effect imo.

 

If in fact you do have a perfectly healthy engine after all these years with low levels of blowby then I wouldn't worry about it.

[Tricky-Ricky]

Tested mine with and accurate vacuum/pressure gauge on a 60K motor, hybrid turbos running 16psi, which is where i came up with the figures...or lack of them, also when i switched back to a catch can the amount of oil vapor was very minimal, mostly water from condensation, but if pipe lengths are reasonably long and the can has some form of separator or filled with scourers the amount of oil that actually gets back into the intake is virtually zero, sure a little contaminated air but its not going to be a problem unless your trying to wring every last ounce of power from it.

This never changed when i then fitted a much larger single turbo, i mainly did this testing to put to bed the IMO completely wrong theory that front main seal failure was down to crank case pressure build up, which in 99% of cases its down to a worn oil pump.