Welcome to Just Commodores, a site specifically designed for all people who share the same passion as yourself.

New Posts Contact us

Just Commodores Forum Community

It takes just a moment to join our fantastic community

Register

What Is an Oil Catch Can, and Why Doesn't Every Car Have One?

immortality

Can't live without smoky bacon!
Staff member
Joined
Apr 15, 2006
Messages
15,471
Reaction score
3,599
Points
113
Location
Sth Auck, NZ
Members Ride
HSV VS Senator, VX s2 Calais S/C
Done right water/meth works wonders. They make good use of it in the US but you need to tune for it. I've got it for a L67 :)

I'm just working on the PCV system and getting a catch can in there to stop the oil going through the blower first. Already with minor changes the oil consumption seems to have dropped significantly.
 

MACE

Well-Known Member
Joined
Mar 30, 2008
Messages
3,154
Reaction score
67
Points
48
Water Injector FTW, but will save that for another tech post :D (if done properly :p)

This aside,
You do indeed. This kit won't have an intercooler system developed until early 2019. Poor man's alternative ;)
What supercharger kit are you running?

Cheers,
Steve
 

Pollushon

Boost gives me a bar....
Joined
Nov 9, 2012
Messages
2,098
Reaction score
147
Points
63
Location
Canberra
Members Ride
VY SS
Hey Steve. Couldn't agree more these kits are pushing upwards of 360rwkw safely on stock. It's by a mob called WASP. An Eaton M122 with a custom manifold and LSA injectors plus all the bits to make it work. Pretty much straight off a Mustang. Designed and commissioned by an ex jet boat racer and engineer out of Melbourne.
 

Mike Litherous

Active Member
Joined
Jan 18, 2016
Messages
276
Reaction score
128
Points
43
Location
Melbourne
Members Ride
VE ssv
The fundamental idea of a closed “catch can” is to seperate the oil/vapor mix so that more vapor and less oil make it into the intake. It’s basically a velocity reduction vessel so the heavy oil droplets fall and are returned to the sump.

It’s more of a problem under high rpm loads like in circuit racing. On my BM’s the oil/air seperator stops the plumes of smoke at high rpm. So for normal use it’s prob not an issue hence one is not on my work Ute. If u are spinning the LS engine up over 6000 all the time then it’s prob a good idea or if u have excessive oil in the intake.
 

immortality

Can't live without smoky bacon!
Staff member
Joined
Apr 15, 2006
Messages
15,471
Reaction score
3,599
Points
113
Location
Sth Auck, NZ
Members Ride
HSV VS Senator, VX s2 Calais S/C
The fundamental idea of a closed “catch can” is to seperate the oil/vapor mix so that more vapor and less oil make it into the intake. It’s basically a velocity reduction vessel so the heavy oil droplets fall and are returned to the sump.

It’s more of a problem under high rpm loads like in circuit racing. On my BM’s the oil/air seperator stops the plumes of smoke at high rpm. So for normal use it’s prob not an issue hence one is not on my work Ute. If u are spinning the LS engine up over 6000 all the time then it’s prob a good idea or if u have excessive oil in the intake.
A catch can is an external vessel that collect the oil and considering that sometimes it's not just oil so ideally you don't want it going back into the sump.

More modern engines are starting to incorporate better oil/air separators into the factory PCV system unlike older engines where the PCV breather is normally only protected by a rudimentary baffle on the end of the rocker cover.
 

07GTS

Well-Known Member
Joined
Sep 8, 2013
Messages
2,220
Reaction score
673
Points
113
Location
Australia
Members Ride
VEGTS BLOWN E85
A catch can is an external vessel that collect the oil and considering that sometimes it's not just oil so ideally you don't want it going back into the sump.
yep i think most would be amazed at the amount of condensation a cold to operating temp engine makes, just from one warm up i could almost fill a elite catch can with fuely smelling water from the crankcase breather, that's if u only vent to catch if u have it back to vacuum it will go into cylinders so u wont notice it, u don't want that going into the oil
 

monstar

Naturally as-pirated
Joined
Feb 1, 2016
Messages
2,476
Reaction score
1,664
Points
113
Age
53
Location
depths of Hays Inlet
Website
facebook.com
Members Ride
Peugeot 207 GTi
yep i think most would be amazed at the amount of condensation a cold to operating temp engine makes, just from one warm up i could almost fill a elite catch can with fuely smelling water from the crankcase breather, that's if u only vent to catch if u have it back to vacuum it will go into cylinders so u wont notice it, u don't want that going into the oil
But the can is a condensor, the engine is not, at least during normal, operation.
Water vapour is not going to hurt the engine, you can’t stop it anyway, is part of combustion and exposure to atmosphere.
There is no requirement to intervene unless the PCV is ineffective, and or is not port injection. At least no longevity or performance basis apart from coke and soot with DI.
 

immortality

Can't live without smoky bacon!
Staff member
Joined
Apr 15, 2006
Messages
15,471
Reaction score
3,599
Points
113
Location
Sth Auck, NZ
Members Ride
HSV VS Senator, VX s2 Calais S/C
Condensation in the catch can was the first sign of intake gasket failure on my old VN. Previously only ever had a small amount of oil in it, because the gaskets failing is a slow process looking at the coolant level in the expansion tank didn't give any sign of impending doom. Once the gaskets were replaced it went back to only catching a small amount of oil.

Interestingly enough, it is the PCV system that introduces a lot of the moisture into the crankcase, yes some will come from the combustion process but that will only be a very small %age compared to what flows through the PCV system unless your engine is stuffed and has a huge amount of blow-by. Next time you have the bonnet up and the engine running remove the engine oil filler cap and listen to the revs rise. Any time during high vacuum engine operation a decent amount of air flows through the PCV system.

The function of the PCV system is in the name (positive crankcase ventilation) and it does this by using clean air from the air intake system and as an unintended consequence you get oil vapour through the PCV system as well as the obnoxious blowby gasses the system is designed to remove. There is no reason to want or need any oil in the air intake, the engine does not need it.
 
Last edited:
Top