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180 wanabe

Catch can questions

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I have a ASE catch can that has been collecting dust for years that I purchased it for my 180sx, but sold the car before I got around to installing it

 

Figured I may as well install it on the S15

 

Feel free to correct/point out anything which is wrong

 

Did a bit of searching about catch cans and came up with a few things

 

The PCV valve "back of the rocker cover same side as the plenum" is one way and wont vent blow by gasses when the car us on boost. It will however open under vacuum and allow blow by gasses to be vented/sucked into the plenum and thus get burnt off.

 

Because of this there is no real need to hook up the catch can to the PCV valve

 

On the turbo side of the rocker cover there is an outlet at the back of the engine which gets left alone "think it drains back to the sump or something"

 

On the turbo side of the rocker cover in the middle, there is an outlet which is connected to the intake elbow of the turbo. This vents blow by gas into the intake which is then burnt in the engine along with the normal air which has been sucked in.

 

So basically I would want to hook up the catch can to this outlet to capture blow by gasses rather than have them burned off. But what do you do about clogging/plugging the hole in the turbo elbow ?

 

The picture I have attached pretty much shows what I was wanting to do with my catch can, would have a hose running from the catch can with a breather on the end discretely stashed out of view to vent the gasses.

 

Setting up the catch can like this should be ok? I know that the EPA conscious folk wont bee to happy but out of sight out of mind.

can.jpg

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looks about right. depending on if your catch can has baffles or not is another thing.

 

that is essentially how its hooked up.

also,

the PCV can get f**ked out over time, goo didea to replace it ! spesh with the size of that turbo, your prob running decent boost too...

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Nar thats not my engine,

 

running a HP5130 but having some issues with detonation if pushed past 18psi

 

want to at least get 20psi which aparently is where the fun starts to happen

 

Thinking that the catch can and a step colder plugs than the stock ones i'm using might help a bit

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less timing then dude.

 

go a 7 heat range plugs without a doubt!

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way you are going to hook it up is crap. you want the crankcase to be a vacuum. it helps your rings seal.

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way you are going to hook it up is crap. you want the crankcase to be a vacuum. it helps your rings seal.

 

whats the best way to hook it up bling? is it the same way but blocking the pcv as well?

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way you are going to hook it up is crap. you want the crankcase to be a vacuum. it helps your rings seal.

 

Ok so how should it be hooked up?

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either run the other side of it to the intake pipe, or get a moroso check valve welded into the exhaust and plumb it into that.

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Any chance you could post up a pic of a setup like the ones you mentioned above?

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It is pretty straight forward.

 

PCV - Leave it (just make sure it functions correctly)

 

Hose from crank case goes into rocker cover on the exhaust side at the rear.

 

Hose from middle of rocker cover goes into intake side of catch can.

 

Hose from discharge side of catch can goes into intake (before turbo and after MAF) or exhaust after turbo.

 

Like said previously, having the crank case under vacuum is a good thing as it aids to seal the rings.

 

This is why your catch can does not need a little filter. It should be a sealed unit.

SR20DET Catch Can.JPG

Edited by Deadly Nedly

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This is how I have my S13 set up. S13 standard "T" piece is terrible, hence the rocker cover modification at the rear passenger side.

IMAG0455.jpg

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Hmm I wonder what the trade off of having the crank case under vacuum vs having the blow by gasses vented and the crank case not under vacuum?

 

Obviously oil vapor going into the engine to be burned off is going to have an effect on knock as it makes the air fuel mixture more prone to ignition compared to an air fuel mixture without oil vapor. Is this benefit enough to outweigh the better ring seal?

 

Now the way I was going to have the catch can hooked up would still allow the PCV valve to function

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like i said, if the crankcase is under vacuum, the rings seal better. therefore less chance of blowby...

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like i said, if the crankcase is under vacuum, the rings seal better. therefore less chance of blowby...

 

Double entendre

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This is how mine is/the best and easiest way to do an SR (has new pcv valve aswell on other side of rocker cover)

 

Turbo pulls the vapours out of a baffled catch can via its intake pipe after the afm

 

IMG_193628995803_zps087d3827.jpg

Edited by brent47

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