Oil catch can/ Breather

[mic*]

Those pieces of intake probly look less greasy than 99% of cars on the road.

I wouldnt be worried about what you've shown. I've heard ppl suggest that a bit of oily air keeping the throttle butterflies greasy is a necesary thing so you dont have to do it yourself.

Personally i think, use a catch can so your performance motor wont recirculate excessive amounts of oil. A bit of grease is your friend tho. It will stop surface oxidation of the whole inlet due to humidity.

Even use a little paper filter before where your PCV system (or catch can outlet) plumbs back into your intake. I have done this before when my paranoia about the oil was a bit stronger myself...

[Hydra]

Correct me if i'm wrong, but wont having oil in the air/fuel mix lower the octane rating, increasing the chance of detonation? I have been considering a catch can for this reason. However the one i'd use would not vent to atmo, but simply be filled with steel wool. It would also have a drain hole at the bottom and maybe some form of plastic pipe on the side like many aftermarket items have.

There'll still be some oil in the air i'm guessing, but it'd be greatly reduced which can only be a good thing if i'm correct in saying the oil is bad for the combustion process.

[oldcorollas]

Correct me if i'm wrong, but wont having oil in the air/fuel mix lower the octane rating, increasing the chance of detonation? I have been considering a catch can for this reason. However the one i'd use would not vent to atmo, but simply be filled with steel wool. It would also have a drain hole at the bottom and maybe some form of plastic pipe on the side like many aftermarket items have.

There'll still be some oil in the air i'm guessing, but it'd be greatly reduced which can only be a good thing if i'm correct in saying the oil is bad for the combustion process.

uh huh..

steel wool canister>> paper filter..

what happens to paper when it gets wet/oily? air no longer passes thru.

[feral4mr2]

Correct me if i'm wrong, but wont having oil in the air/fuel mix lower the octane rating, increasing the chance of detonation?

thats how i see it too.

but simply be filled with steel wool.

use stainless scourers, steel wool can deteriate and break up over time, you dont want any of that being 'sucked' into your intake if you are plumbing it back. the idea of the scourers is to catch oil in the dirty air/vapour as it's sucked up past them, which then allows the oil thats caught to slowly drain/drop to the bottom of the can and let 'cleaner' air return to the inlet.
i made one with PVC, some garden fittings and stainless scourers ages ago.


1 vent on top of the catch can which at the moment i have a small k&n filter, but can be plumbed straight into the inlet before the turbo if i wish.
2 cam vent inputs.
1 drain, which i do not return to the sump, ever seen how much water can collect in a catch can?.

[mic*]

Ill try find a pic of the paper filter i mean. Its like a tiny little baby pod with a 3/4" hose into it. I sealed a cup around the other side. It would get oily with time. Then i could wash it out and start again. Was not restrictive even when saturated.

Hydra what you say about oil in the combustion is reasonable, but the amount makes it negligable if you use a catch can.

I dont think you will/would find any measurable reduced tendancy for knock when you install a can.

And, even without a catch can - from brand new i estimate a car would take at least a few years of residue building up to increase the ONR (octane number requirement) of your car as much as a hot summer day would.

[Hydra]

This is true, but on an engine thats getting to be 20 years old it should help a little more. I guess every bit would count in the end.

[mic*]

I guess i feel like ive been on that side of the fence - being paranoid bout it.

The way i think about it now is - i know that its insignificant in terms of affecting the tune of the vehicle. Ie, you wont get more timing advance...

And i know that there is no way my manifold will ever spend years on the car without getting overhauled. Doing all this pedantic stuff seems a bit of a waste of effort when you know you'll clean it out next time you pull it off - whether it LOOKS dirty or not.

And... i dont place a lot of value in it but ppl will tell you that the oil keeps your throttle butterfly & ISCV (depending on type) lubed. I think there is probably more truth in the stories of rust occuring without the oily surface.

[JZA70 R]

I am really interested in this topic. If been thinking of the most efficient setup of a CCV system for my 1JZ.

I guess its not much different to any other motor in regards to the oil breathing system.

Basically you have a PCV on the cold side of the motor sucking from one cam cover under vacuum straight back into the motor via your plenum.

Then on the hot side of the motor you have a larger port on one cam cover that vents directly to PRE turbo, therefore that would be at vucuum 100% of the time.

I dont like either of these oil breathers despite their simplicity, because of the following.
The cold side's oil breather is just sucking blowby back into the motor directly mixing with the A/F and lowering the octane or what have you.

I dont like the hot sides oil breather because...
1. both turbos are being hit with blowby
2. my intire intake system including turbos, intercooler, piping and the throttlebody are being coated with oil.
The intercooler is my biggest concern being a aftermarket item, i cant help but wonder how less efficient it is being internally coated with oil!

Now just recently i have disconnected the hot sides oil breather from the preturbo intake and have attached a simple filter for the time being. The filter catches most of the oil and i guess it just makes its way back into the cam cover. Im wondering just how 'bad' this method is but i wasnt prepared to soil my new intercooler .

The cold side is still attached as factory and im now waiting to find the 'right' catch can which incorperates the following...
appropriate sized fitting for a 1JZ's oil breather ports on the cam covers.
super efficient baffling system that can be routed back to pre-turbo.
oil drain to sump provision
servicable.

I have yet to find such a catch can and am now considering having something fabricated.

To touch on someones comment about the difference between having a vacuum on the crank case and actually having the crank case breath fresh air under vacuum...
Is it possible to somehow tap a breather directly to the crank case to aid breathing of the whole system?

[Toycrash]

The flaps DONT need to be lubed by anything, thats why they started to use roller bearings at late '70s.
Even my setups on those pictures arent the messiest, the flaps were allready sticky and jammed.
Every bit of oily carbon is bad for airflow.

I understand manufacturers have to do ccv like this, but I DONT and i wont

[Hydra]

I cannot see why you would want oil anywhere in the intake system on most engines? They don't use metals that are likely to rust anyway

I know that in the end the difference may be insignificant but hell, anything that helps prevent knock is good in my book!!

[mic*]

The idea that you can run different (better) tune if your PCV system vents to air as opposed to using a catch can plumbed back into your intake is a bit exaggerated.

Hardly any volume of each compression stroke is actually gonna be blowby that is recirculated.

And furthermore after 95% of the suspended oil is removed by the catch can how much oil is in the already miniscure volume?

Ive said it before but a hot day will play with your ONR more.

The biggest performance gain would be smoother airflow throught the intake... still buggerall.

If you vent to air i think you're a bit of a noob who doesnt care about the environment and wants to save 10 minutes cleaning next time they do a 3 hour overhaul of their intake.

[monkeymajik]

I dont think there are many people who vent to the air without a filter. And a vast majority of those that do, have a car that came like that from factory.

[mic*]

I dont think there are many people who vent to the air without a filter. And a vast majority of those that do, have a car that came like that from factory.

Good...