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Catch Can Question

wangan ghost
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wangan ghost Rookie

wangan ghost

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Hi. i have a R34 25GT-T with a GT30R with stock internals, i was wondering if it would be necesary to have a oil catch can with this setup or when is that you really need one in a rb25.

Im not planing to go over 20psi or over 7500 rpm

thanks

Giancarlo

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09ONE_32 Collaborator

09ONE_32

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A catch can always a good idea.

At taht level of boost if you are hitting redline and pedalling the throttle a lot you will begin to get blow by issues. A catch can will collect the oil vapour/mist that comes out of the roker cover breathers when you get off the throttle after full boost.

wangan ghost Rookie

wangan ghost

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A catch can always a good idea.

At taht level of boost if you are hitting redline and pedalling the throttle a lot you will begin to get blow by issues. A catch can will collect the oil vapour/mist that comes out of the roker cover breathers when you get off the throttle after full boost.

when you say blown by issues you mean oil coming out issues or other type of issues?

09ONE_32 Collaborator

09ONE_32

Posted
Posted

Yeah blow by is gases from combustion squeezing past the piston rings or past a cracked piston or ringland and pressurising the sump. This will cause oil to be sucked into your turbo if your oil breathers are connected to your intake (factory setup). If you start getting alot of blow by, oil will begin to leak out of the BOV if you have an aftermarket one and out the oil filter and possibly the dipstick.

Basically just hook up a catch can to stop any oil vapour from being re-circulated through your intake system.

wangan ghost Rookie

wangan ghost

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Yeah blow by is gases from combustion squeezing past the piston rings or past a cracked piston or ringland and pressurising the sump. This will cause oil to be sucked into your turbo if your oil breathers are connected to your intake (factory setup). If you start getting alot of blow by, oil will begin to leak out of the BOV if you have an aftermarket one and out the oil filter and possibly the dipstick.

Basically just hook up a catch can to stop any oil vapour from being re-circulated through your intake system.

Ok in a catch can reconected to the block, everytime i lift the gas the vacum will suck all the oil back to the engine preventing any leak or blowing?

(OO)SKYLINE(OO) Grand Master

(OO)SKYLINE(OO)

Posted
Posted

From my understanding of a catch can, its to catch all the oil fumes so it does not go into the air intake.

Then you gota empty it out and all this yuck claggy shit come out of the can.

And I think you might have to do a bit more of a regular oil top up.

I had one but the previous owner did not pipe it correctly and had a hose from the catch can leading out to the atmosphre and oil was basicaly evaporating out.

Unless for race applications, I don't think you need it.

So it allows your engine to 'breath', sorta...

blind_elk Grand Master

blind_elk

Posted
Posted

If it's installed correctly, it's actually an oil-air separator. As the oil-vapour laden air passes into the canister, the oil condenses out, leaving just "clean" air to continue on to the induction side.

(OO)SKYLINE(OO) Grand Master

(OO)SKYLINE(OO)

Posted
Posted
If it's installed correctly, it's actually an oil-air separator. As the oil-vapour laden air passes into the canister, the oil condenses out, leaving just "clean" air to continue on to the induction side.

Cool thanks!

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