JDS Performance

Please contact me on this - we might be able to get something going..
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s13ontap

maybe this has been asked...... To the topic of venting, not power...

wouldn't an aftermarket air/oil separator do the exact same thing?

Moroso : Category Display

I found this thread cause I've got a built motor now making high boost, and my catch can is filling like crazy now.

I was considering welding a bung, or doing a conversion valvecover, but I just shaved and polished my s13 valve cover, and i don't want to do it again....

anyone?

huffandpuff00

The 13.4/modified s13 VC will reduce the amount of oil that makes it to a catch, so it wont fill up as quick. u should still run a catch can with an s13.4/modified VC.

Here is the can i use: Saikou Michi Co. 2013

ryandriftingfat

I understand this is kind of a contentious issue but wanted to see peoples opinion of mine.

I have the front of my T capped.
The rear of the T is run into my catch can AND is T'd into the drain fitting behind the turbo.
The PCV on the intake side is replaced with a hollowed fitting and also run to my catch can.
My catch can vents to atmosphere.

I have never, across either SR cars, had issues with filling up my catch can. Even now after 4 full track days, there's not more than a little film of oil in my can. Both were S13 SR's with stock VC's.

So no issues filling my can and no oil in my intake tract. Unless I'm going to blow something up I have no plans to change it.

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Kingtal0n

It sounds like you are sending boost right into the atmosphere. If you have a "hollowed fitting" you mean empty, such that boost from the intake manifold can run right into your catch can?
The T should not be capped either. Not to be mean or rude, but you obviously have no idea what you are doing. This is the 14th page of this post, did you read through pages 1-13?

I just want to point you in the right direction. the idea is to pull a vacuum on the valvecover. I dont care if you use a vacuum pump or the engine as the pump or the exhaust as a scavenging utility, use all three if you can all at once. The better the vacuum you can pull on the crank case, the cleaner the oil will be, the better the ring seal will be, the more power you will make.

Consider this. A vacuum present at the valvecover will also be present in the oil pan. The head is connected to the block, and there are holes for the passage of oil from the head, to the oil pan. That said, you could technically fabricate a pcv system that pulls vacuum from the engine block instead of the valvecover, there is simply no good reason to however.

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ryandriftingfat

Definitely appreciate that. I'd appreciate it if you'd read my post too because you made two big assumptions that were wrong. If you seriously think I'm spitting boost into my catch can after a few track days and not noticing myriad other issues, I'm not sure I want your advice. Nothing in my post should put that in your head.

No no no no. Intake side. The PCV on the VC is hollowed (so I don't need to pull vacuum across it to open it). Also, the front of the T is capped off, not the whole thing.

I have read a significant amount of this thread - there are a lot of different ways, none of them being utopia unless you have some way of pulling vacuum across the head without oiling up the intake tract. (yeah yeah vent into exhaust is one way)

So again, unless there is something seriously wrong that is going to blow up my motor, I'm not changing it. This is just another way of doing it. It's not perfect but few are.

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Kingtal0n

Ok help me understand. The intake side, to me means intake manifold side. make sure you are using the right terminology. The intake manifold side of the pcv system has a 1-way check valve to prevent boost from entering the valve cover. The compressor inlet is not the "intake side" because intake usually means intake manifold. Are you saying that your compressor inlet, that contains the air filter, is connect all the way around to the valve covers one-way check valve on the other side of the engine? Or are you saying your one-way check valve on the intake manifold is "hollowed out" because thats what it sounded like.

A picture is worth alot here.

Also, did you ever put your finger on the front of the T with the engine running? Why dont you try that and get back here with what you experience. Right now, it sounds like you have absolutely no positive crankcase ventillation, only a route for oil in the event blow-by suddenly gets real bad due to ring failure.

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quickdiversion

If he is taking about the intake side of the motor, than the only thing i can think of that could be hollowed out is the one way check valve, or pcv valve. Which is also not a good idea. As it is designed to close once vacuum is noticed on the crack case.

If i remember correctly, it allows in air for atmospheric pressure at idle, than in throttle it closes to help create vacuum. Vacuum is created on the exhaust side of the motor via mentioned in previous methods. If the T is blocked than there is no where to go besides in to the vc unless he has something else pulling vacuum.

Thus leaving him with positive crank case pressure on throttle. This leads to the motor working harder to rotate due to the pressure under the pistons, also the pressure on the rings can cause excessive wear over long periods of time. It can also lead to a blown mirror because of to much pressure.

His only saving grace that i can think of that would keep him from blowing is if the pcv valve was hollowed allowing a small amount of vacuum. Provided it is hooked up to a vacuum source.


Write on my phone at work. Sorry if it is short

ryandriftingfat

I think you both have the wrong idea of what I've got. Not saying that "if this then that" that you're saying is wrong, only that your assumptions are wrong.

EDIT: I should also mention the two nipples on the intake runners normally connected to the PCV are also capped.

This picture sucks but you can kinda see:


Basically this diagram:


My VC is not pressurized and VC breather/venting is isolated from the intake and exhaust.

So again. I'm not saying this is the best way, I accept that positive vacuum is the preferred way. This is what I decided on and I've made my decision on oily pipes vs perfect setup. There are too many examples of various configurations that run fine to get too worked up over this.

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quickdiversion

Looking over your diagram you have no vacuum or crank case relief.

Be careful dude, your on borrowed time.

EsChassisLove

My PCV valve, brand new, still lets oil past and into my intake manifold. Not sure if its normal or not but I'm about to run a catch can in between the two.

Any input?

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quickdiversion

Your pcv will still let oil pass. Have you ever modified the lines that go from the fuel rails to the pcv valve?.

I ask this because if you have then you might not have noticed that there is a restricter. That allows the air but because of the size, it usually does a decent job blocking the oil. Obviously it still lets some through. But just a heads up. First picture posted is of the restricter.

The second picture is of my setup, which is exhaust evac. Mainly you use the power of the exhaust flow to increase the vacuum siphon in the crankcase and head.

idahotuner

the is why my original motors rings went, this new motor is using the intake just haven’t had time to set up the exhaust for extra vacuum

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akara

I have read this whole thread as well as many other threads on the sr20 PCV system and I cant find any repeatable dyno proof that a closed PCV system will make more power by promoting ring seal. Anyone know where I could find some facts on this? maybe I will unhook my pcv back to atmoshphere next time I am at the dyno and let you guys know if I lose any power, but I dont think I will.

EsChassisLove

My vac line goes straight from my PCV to my intake. Doesn't go to my fuel rail at all. I'll have to try and find a restrictor for it. It's a small amount of oil but I still don't like it on a brand new engine.

SR20s seem to love blowby also

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quickdiversion

There is no need to dyno the facts. The facts are in the simple mechanics of how a motor works.

I'll explain this again.

When a motor is at idle, the pcv valve is used to allow the crankcase to pull in small amounts or air into it. This method is used at idle because there is no vaccum on the system.

When you hit the gas the car goes into vacuum in order to run, I won't get detailed about that. Now the vacuum pulls the pcv valve closed and now must find it from another source. This is where the large tube by the turbo comes in.

In the stock "T" design it was used by the inlet of the turbo compressor, in the plastic intake tube. to pull vacuum from the case and the hv at the "T". This is stock setup.

The S14 uses a different system that eliminates the "T" and has better baffling in the VC.

Now, the engine mechanics part again.... If the motor can not pull vacuum under throttle, the pressure will rise in the crank case from the force of the motor pounding away at the air under the rotating assembly. To much pressure and pop go yout rings, and other things.

In order have proper flow in your crankcase you need to have it in vacuum to decrease resistance in the crank case and keep pressure down.

Now lets think. TO much pressure under the pistons will will increase the stress on the rotating assembly and can cause ring failure because the pressure.


Now, doesn't it seem like a good idea to pull that pressure out with vacuum?

quickdiversion

Sorry didn;t mean the fuel rail. I meant off the soft line, it goes to a metal "T" and then into the long runners. Yeah a spacer is easy to make for that. Go to Home Depot and look for a small spacer for spacer a bolt away from where it secures. grind down the outsides till it slides into the line. poof

akara

This is the way I understand it,
When a motor is at idle, the pcv valve is used to allow the intake manifold to pull vacuum on the crankcase (my car idles at 20mmHG). The restrictor and check ball prevent too much oil getting into the IM, and prevents boost from entering the crankcase.

doesnt make sense to me, the PCV check ball closes under boost, not under part throttle vac. My car has vacuum from idle until 20% throttle. Once this checkball is closed and the engine is in boost, the crankpressure is directed straight out a breather to atmosphere, so it doesnt build up any pressure.

This also doesnt make sense to me, because I was wondering about a atmospheric PCV is not sealed so no pressure builds up in the crankcase at all.

Interested in your thoughts. It's a trivial matter to unhook the hose on the dyno and actually get some real evidence, so I will be sure to do that as soon as I can

The way I see it, pulling 20mmHG(.4psi) vacuum on the crankcase VS none at all will only change the pressure differential of the crankcase/combustion chamber by 2%, hardly enough to notice.

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http://www.strokerengine.com/vacuumpump.html

this is actually a common modification among the big horsepower V8 crowd. its percentage based, the more displacement, the more boost, the more payback.
And you have to actually be making power, to notice a difference in power.

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Kingtal0n

and for ryandriftingfat, I agree with what others posted about your setup, with all due respect you need some form of pcv. Every auto manufacturer of every engine in the world has included a functional pcv system with their engine that Im aware of since it's benefits are realized. removing it is not a good idea. This is about having a cleaner healthy engine.

some good info about POWER gains while using vacuum pumps in this thread:
http://www.performanceboats.com/dyno...um-pump-3.html

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akara

Thanks a bunch! I totally agree with you like you said that its percentage based, the more displacement, the more boost, the more payback.
In your example the 25hp gain equates to about 2.8%, in line with what I was thinking.
I will be curious to see the difference when I am on the dyno as I am only making around 300WHP(guesstimate) on a 2L

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quickdiversion

I have noticed a huge difference on my setup. I originally can of the left of the "T" into a catch can and then into the intake line for the compressor. The problem with that was in pulled so much oil from the VC that the can would fill and get sucked into the compressor. Had to tear my entire turbo and exhaust side apart because I thought I blew the turbo. I didn't but what I did notice is that the valve seals were starting to leak. I am talking new valve seal with less than 15k miles on them.

I went from a 2871r making just under 340 hp with nice linear power, to an hx35 twin scroll and swapped to an external gate. No dyno yet because I just got the exhaust and hot side done but I was able to take it out for a spin with half the old turn and a recalculated fuel map (Its good to have a stand alone) I can not only feel the difference when driving it, but at idle you can hear the air flow from the exhaust evac. Even though the holes for the baffling are small its pulling hard.

I just took all the exhaust apart to look for oil and smell for oil, and nothing.

So while it looks like alot of work it cost me less than 150 bucks to run the exhaust evac. The bung and insert were like 30 from Vibrant, -8 AN hose was like 5, the fittings were 60 from summit, and the welding was 50.

So its not a super expensive upgrade, but then you never have to worry about it, having blow by, or in my case, getting oil into your compressor.

Motosx

(quickdiversion) a pic would be nice.

quickdiversion

Of which part would you like, I have lots of pictures of my setup. lol

Motosx

Just of the catch venting ext...

quickdiversion

my exhaust and intake side, no catch can on the exhaust side, catch can on the intake, between the pcv valve and the intake plenum.

Croustibat

Approx. none.

Serious drag racers use vacuum, but they also use 3+ bar boost, and put cement in the block cooling system to prevent it from cracking.

Having the crankcase under vacuum is good because the oil return line from the turbo has to be at lower pressure than around the turbo seals, otherwise oil goes where there is less pressure. Crankcase with pressure = oil in exhaust and intake. You dont want that.

Crank does create pressure from its pumping effect, and rings always leak some pressure when used with high boost. Using vacuum at the crank case allows for a more secure oiling system, as pressure will also be lower at the crank case than in the head, allowing oil to be sucked back from head to crankcase instead of just depending on gravity.

But for low boost on small 4pots (i'd say up to 2 bar boost), you can just stick a huge breather between cam covers and crankcase, and vent it to atmosphere. It will work enough. The vacuum system would be better, but power wise it should not change much. Not worth the money to do it if you are after HPs IMHO.

Manufacturers dont do it anymore for 2 reasons:

1/ emissions - it just is illegal now to vent to atm. Oil vapors are required to be recycled, one way or another. Most of the time they are just injected back at the intake and burned. On some cars, there is a closed catch tank and oil condensates back.

2/ fire hazards (oil vapors released under a hood may burn)

The problem with a catch tank that vent to atm is that it is often filled with water condensation, that goes in your breathers at night ... and in your cam covers, and in the crank case. Remember to empty it often, or to close it when not used... If you dont and it fills up, it will prevent any breathing, and you will get pressure in crankcase, thus oil going through turbo seals.

akara

Thanks for the photos, I have mine set up to vent to atmosphere for the same reason, because I dont want any chance of oil getting in my compressor. I am the kinda guy whos checking everything under his hood every day so I havent had a problem with the can filling up yet, but the exhaust evacuation seems like a great idea to me.
One question for you, it seems like you have the bung for the PCV welded on your downpipe perpendicular to the air stream. A lot of places say you need to have it at a 45 degree angle to get the venturi effect. Have you noticed any exhaust coming out of that hose at low RPM/idle or does it pretty much always draw vacuum? Thinkin of venting my can to exhaust as well.

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quickdiversion

the bung is cut on a 45* angle and welded on a 45* of the down pipe. lol so it looks straight up and down, but it is not. If it were it would not work at all because there would be no way for the exhaust to pull enough air through it. when it is not in vacuum it does puff a tad of smoke, but if you blip the throttle with your hand on the hose you feel it sucking the air into the hose

akara

ahhhh cool thanks i get it now that Ive seen the full pic of the insert
I just found the Vibrant fitting you used on summit as well as some Moroso instructions in case any one else is interested.
http://www.moroso.com/catalog/images/25900_inst.pdf
Just bought the fitting Vibrant 1189, I'll install mine with a 1 way check valve to prevent exhaust going into the VC at idle and it should be great!

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