SR Owners... More HP Easy Mod... Catch Can Setup - Page 17 - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

hobbs · 12-12-2014, 07:12 AM

Quote:

Originally Posted by slider2828

You would have to plumb it an extra pipe and also the opening is pretty small. So I would say it wouldn't help too much....

Not to mention the carbon and all the other crap the oil mixes with when going though the baffles you don't want that shit back in your motor. Also depending on climate water can collect in your catch can, also don't want that returning back into the sump.

sil14zenki · 12-12-2014, 09:30 AM

Quote:

Originally Posted by Kingtal0n

1. Its nice work. good job emulating the oem setup with the integrated catch can, for the situation in which the engine explodes and oil comes pouring out.

2. Let me ask you, if you take a random tube, and suck on one side with your mouth, what is the pressure differential inside the tube?

I think we need more physics and less random adding containers to our engines. This is what I see happening, "look guys, I added a container where there used to be none. And it stays empty! (why did I add it?)"

let me explain then.
i had the stock setup and with a 2871r @21psi it was filling up every week.
and now with this setup that's a cheaper alternative to the s13.4 cover,
my catch tank is empty.

Kingtal0n · 12-12-2014, 10:29 AM

Quote:

Originally Posted by slider2828

You would have to plumb it an extra pipe and also the opening is pretty small. So I would say it wouldn't help too much....

Also lets see this part as what it really is, just another hole in your valve cover. Some companies make shit just because they think they can sell it to somebody. It's like somebody made a "race engineering kit" that consist of a drill bit and a sticker, for you to drill a hole in your valvecover and say its for "oil control boost overflow" and people would buy it.

Quote:

Originally Posted by slider2828

Long story short, if it is a stock engine running a stock turbo, then this mod won't help too much. But with higher horsepower cars that run higher boost and turbos, then it would help.

Lets jump right to the point with this. There are two issues here, one is oil control, the other is crankcase ventilation. The oil control feature is part of your valvecover, there should never be any oil coming out of anyone's valvecover to begin with, and if there is, it is a problem on any engine. Some engine's are more likely than others to cough up oil from their valvecovers during certain situations, like the S2000 engine when it is beaten on a track. Those guys are actually drilling holes in their valvecover's baffle to help control the oil, and they are running a catch can just to catch anything that comes out. But it should not be there to begin with, and the issue was addressed by the manufacturer at later years. If you have oil spilling out of your valvecover, a catch can is just a temporary solution so you can drive the car while you try to fix the real problem. For some, it becomes a permanent solution because they do not know why the oil is there, or how to stop it.

The second issue is crankcase ventilation. You desire a pressure below atmospheric inside your engine's crankcase, plain and simple. During boost, the only place to find that, is right in front of your turbo. So the manufacturer did us a favor and did some math, and decided that they would run a short line with a small restrictor directly from the crankcase to this location. And that is as good as it is going to get, as anything we do, adding miles of extra plumbing, and removal of that restrictor, will all diminish the vacuum signal that is already so weak to begin with.

*TheRealSy90* · 12-12-2014, 06:21 PM

Why not keep the Oem restrictor with any catch can setup...

cotbu · 12-12-2014, 07:31 PM

Quote:

Originally Posted by TheRealSy90

Why not keep the Oem restrictor with any catch can setup...

I recommended this, a while ago! This is how mine has been run for years.

Sent from my Slightly Tuned Note 4!!!

Dboyizmlg · 12-13-2014, 01:12 AM

^ I was thinking the same thing.

*TheRealSy90* · 12-18-2014, 10:15 AM

ProTip: How not to oil catch can...

Quote:

Originally Posted by ehhhregartless

*slider2828* · 12-18-2014, 11:00 AM

Quote:

Originally Posted by Kingtal0n

Also lets see this part as what it really is, just another hole in your valve cover. Some companies make shit just because they think they can sell it to somebody. It's like somebody made a "race engineering kit" that consist of a drill bit and a sticker, for you to drill a hole in your valvecover and say its for "oil control boost overflow" and people would buy it.

Lets jump right to the point with this. There are two issues here, one is oil control, the other is crankcase ventilation. The oil control feature is part of your valvecover, there should never be any oil coming out of anyone's valvecover to begin with, and if there is, it is a problem on any engine. Some engine's are more likely than others to cough up oil from their valvecovers during certain situations, like the S2000 engine when it is beaten on a track. Those guys are actually drilling holes in their valvecover's baffle to help control the oil, and they are running a catch can just to catch anything that comes out. But it should not be there to begin with, and the issue was addressed by the manufacturer at later years. If you have oil spilling out of your valvecover, a catch can is just a temporary solution so you can drive the car while you try to fix the real problem. For some, it becomes a permanent solution because they do not know why the oil is there, or how to stop it.

The second issue is crankcase ventilation. You desire a pressure below atmospheric inside your engine's crankcase, plain and simple. During boost, the only place to find that, is right in front of your turbo. So the manufacturer did us a favor and did some math, and decided that they would run a short line with a small restrictor directly from the crankcase to this location. And that is as good as it is going to get, as anything we do, adding miles of extra plumbing, and removal of that restrictor, will all diminish the vacuum signal that is already so weak to begin with.

So after running on the track numerous times, here is my situation which caused me to figure out how to do this mod. 1st under high G load, oil will slosh to one side of the pan and will be picked up into the turbo because the stock s13 setup runs directly into the turbo. The black box air oil separator is overwhelmed when the restrictor is lost between the black box air oil separator and the T that runs to the valve cover. Now in larger turbo applications and high G load, these components are overwhelmed because the car is no longer pulling stock vacuum and with aftermarket headers you can not retain the stock black box air oil separator.

In larger turbo applications, you are going to have a great source of vacuum from the turbo, so why not use that. By ditching the T, and going with an L adapter and a bigger line from the crankcase to the valve cover we can use the head as the 1st scavenger point of oil. Now without a kink in the system like the stock 90 turn, the air oil separator, the inline restrictor, and new larger shorter vacuum line to the valve cover, I think we can agree that this is an improvement.

Now the problem I agree with is that the catch can to the turbo is too far away and may reduce the vacuum due to the longer line. Truthfully the best solution is what someone posted a few pages back, which is from the top of the valve cover directly into an air oil separator into the turbo elbow. This would be the best for performance, but bad for the environment. But I think if you have 18+PSI, I think with the increased length in the line that it will have more vacuum than the stock setup regardless.

Def · 12-18-2014, 11:34 AM

Seriously... that's horrible.

*TheRealSy90* · 12-18-2014, 12:15 PM

I've been considering running a one way valve on the downpipe and pulling the crank case pressure from there using the exhaust flow to create a vacuum. So from the valve cover - catch can - exhaust valve. I noticed it was pretty popular out at the sand dunes on a lot of the various turbo i4 powered rails out there. So what would pull more vacuum, the intake on the turbo or the outlet from the turbo? Also i'm running an s13.4 hybrid valve cover so I no longer have the s13 black box / restrictor -_-.

quickdiversion · 12-18-2014, 12:30 PM

Quote:

Originally Posted by TheRealSy90

I've been considering running a one way valve on the downpipe and pulling the crank case pressure from there using the exhaust flow to create a vacuum. So from the valve cover - catch can - exhaust valve. I noticed it was pretty popular out at the sand dunes on a lot of the various turbo i4 powered rails out there. So what would pull more vacuum, the intake on the turbo or the outlet from the turbo? Also i'm running an s13.4 hybrid valve cover so I no longer have the s13 black box / restrictor -_-.

You don't need a hybrid valve cover. If you look back a few pages I posted pictures of my exhaust evac with a check valve. It is not difficult but you need to use steel tube and flare nuts coming off the exhaust cause the heating and cooling will warp and ruin the aluminum. I will repost the pix if you want.

***S14DB*** · 12-18-2014, 02:17 PM

Quote:

Originally Posted by TheRealSy90

I've been considering running a one way valve on the downpipe and pulling the crank case pressure from there using the exhaust flow to create a vacuum. So from the valve cover - catch can - exhaust valve. I noticed it was pretty popular out at the sand dunes on a lot of the various turbo i4 powered rails out there. So what would pull more vacuum, the intake on the turbo or the outlet from the turbo? Also i'm running an s13.4 hybrid valve cover so I no longer have the s13 black box / restrictor -_-.

Exhaust breathers only work at idle. There is suction behind each exhaust pulse. Once the pulses start to blend together as rpm increases there is only pressure in the pipe. Works great on things like drag cars and applications that only are on power for limited time.

Turbo intake is going to pull the most vac under load than anything else. The catch can is there to catch any oil and let the gasses thorough to get burnt in the combustion chamber.

Under engine braking(Vacuum on the boost gauge) the intake manifold has the most pull and why the PCV runs from the valve cover to the intake manifold. PCV valve closes under boost if working properly.

blackmags91 · 12-18-2014, 02:22 PM

I read the first two pages, im not gonna read the next 15, especially while im at work haha.. so pardon me if this has been brought up already, but what is the issue with the OE oil/air separator? Why does everyone hate it? (I dont think it's THAT ugly..) I bought my current SR without one and one of the first things that I did was find another one and reinstall it. Nissan wanted it there, its supposed to be there.. So why not?

I also have a greddy catch can between the "T" and the turbo intake that never fills up even on the hardest of track days. Ive had kids at local meets and shit laugh and ask why I have the separator and a catch can, but tbh I dont deal with ignorant kids wearing flatbilled Hoonigan snapbacks that barely have their GED. So please, can someone that's educated convince me to remove the factory separator.

*TheRealSy90* · 12-18-2014, 02:27 PM

I know I don't need it but I went with one anyways since it was a good deal. That's weird I was always under the impression that the venturi from the exhaust flow would always pull vacuum at the valve if it came into the exhaust at a small enough angle, like less than 45 degrees.

Kingtal0n · 12-18-2014, 02:45 PM

Quote:

Originally Posted by S14DB

Exhaust breathers only work at idle. There is suction behind each exhaust pulse. Once the pulses start to blend together as rpm increases there is only pressure in the pipe. Works great on things like drag cars and applications that only are on power for limited time.

Turbo intake is going to pull the most vac under load than anything else.

blatant word vomit, than Anything Else? Guarantee a belt driven vacuum pump designed for crankcase evac on a big block chevy will pull more vacuum.

Exhaust breathers work at idle? People are installing these things to improve their idle crankcase vacuum? What kind of nonsense are you spewing all over the place...

Here are the steps you would need to take to prove that,
1. Install crankcase Evac 1-way valves to the exhaust system
2. Measure the pressure in the exhaust system, compare it to the pressure at the crankcase. If the crankcase pressure is < atmospheric, then it works.|

ya havn't done that, have yeh. your just saying random shit to get your post count up, huh.

I know because I did these things myself when I was 17 years old, on a boosted chevy engine no less.

And it works F*@&#& AWSOME AT ALL RPM. HIGHLY RECOMMENDED.

*slider2828* · 12-18-2014, 03:52 PM

Quote:

Originally Posted by Def

Seriously... that's horrible.

Well how would you run it? Instead of a stupid smug comment....

Quote:

Originally Posted by Kingtal0n

blatant word vomit, than Anything Else? Guarantee a belt driven vacuum pump designed for crankcase evac on a big block chevy will pull more vacuum.

Exhaust breathers work at idle? People are installing these things to improve their idle crankcase vacuum? What kind of nonsense are you spewing all over the place...

Here are the steps you would need to take to prove that,
1. Install crankcase Evac 1-way valves to the exhaust system
2. Measure the pressure in the exhaust system, compare it to the pressure at the crankcase. If the crankcase pressure is < atmospheric, then it works.|

ya havn't done that, have yeh. your just saying random shit to get your post count up, huh.

Nothing really would work at idle, unless like said belt driven vac pump, which would basically be the best thing.

Kingtal0n · 12-18-2014, 03:54 PM

Quote:

Originally Posted by slider2828

well how would you run it? Instead of a stupid smug comment....

Nothing really would work at idle, unless like said belt driven vac pump, which would basically be the best thing.

Quote:

Originally Posted by s14db

exhaust breathers only work at idle.

\

tell him not me...

... But to be honest my chevy did pull a vacuum from the exhaust at idle. it really did. It just got better with RPM and LOAD.
Exhaust gas scavenging is a well known phenomenon. Anyone want a good read look up David Vizard. You can get more suction from the exhaust system during overlap than you can from the descending piston. This is also the reason why you dont want a large exhaust on a naturally aspirated engine, why it kills low end torque.

*TheRealSy90* · 12-18-2014, 04:06 PM

So what's the optimal angle for the valve to enter the exhaust? Also, where can one of these valves be purchased? I've actually never seen them for sale lol.

jr_ss · 12-18-2014, 04:11 PM

Exhaust venturis create vacuum under all conditions, not just at idle.

blo0d · 12-19-2014, 10:10 AM

@slider2828 what about the newer flat nissan valve covers, how good are they? do they still need this type of modification on RWD?

This thread on the dash forums suggest these VC's are "improved" (post #2)
http://www.sr20-forum.com/informatio...d-edition.html
http://www.sr20-forum.com/informatio...d-edition.html

ixfxi · 12-19-2014, 10:49 AM

Quote:

Originally Posted by Kingtal0n

We have already approached this issue and it is the same as it was when I approached it on earlier pages(1-X) of this thread, that is, as the plumbing increases in length approaching infinity, the effects of a change in pressure at one end are diminished at the other end, to the point of not making any difference in pressure from baseline at the long end. Please refer to the previous examples in this same thread I have already given.

what type of special school did you get your degree from?

*slider2828* · 12-19-2014, 11:51 AM

Quote:

Originally Posted by blo0d

@slider2828 what about the newer flat nissan valve covers, how good are they? do they still need this type of modification on RWD?

This thread on the dash forums suggest these VC's are "improved" (post #2)
http://www.sr20-forum.com/informatio...d-edition.html
http://www.sr20-forum.com/informatio...d-edition.html

Truthfully I am not sure how the valve cover does its baffling and how it pulls vacuum. How I would approach it is look at how it was originally used with any stock air/oil separators or restrictors and how the valve cover is designed, then look at the baffling in the valve cover, then let me know.

I think that is the safest way....

PoorMans180SX · 12-19-2014, 12:41 PM

Quote:

Originally Posted by jr_ss

Exhaust venturis create vacuum under all conditions, not just at idle.

^THIS (sort of).

There is so much misinformation in this thread. The ONLY way you can (effectively) evacuate the crankcase without a vacuum pump or dry sump system is the venturi effect and the pressure present in the crankcase. Whether you route it to your exhaust or your intake, you are still trying to use the venturi effect to draw gases out faster than the pressure would push them out anyway. There is never any "vacuum" in your intake tube or your exhaust.

And unless you have a very well-baffled valve cover, you'll probably be sucking out some oil mist along with the crankcase gases, so you'll need a catch can to catch them, at least if you're running it to your intake tube. If you're running it to your exhaust, it really won't matter much except that it might smell bad from burning said oil mist.

The exhaust evac route is arguably more effective at high rpm, as the gases in the exhaust tube are moving faster and therefore generate a stronger venturi effect, you'll just need a one-way check valve so you aren't blowing exhaust into your engine at low engine speeds.

You can and should mount one of these in your exhaust or stainless intake tube for maximum effectiveness:

Def · 12-19-2014, 12:45 PM

Quote:

Originally Posted by slider2828

Well how would you run it? Instead of a stupid smug comment....

Easy there, killer. I was commenting on this post, but must have hit reply instead of quote:

Quote:

Originally Posted by TheRealSy90

ProTip: How not to oil catch can...

Given that the damn thing forms a loop around the engine and doesn't go anywhere (not much evacuation there).

Def · 12-19-2014, 12:47 PM

Quote:

Originally Posted by PoorMans180SX

^THIS (sort of).

There is so much misinformation in this thread. The ONLY way you can (effectively) evacuate the crankcase without a vacuum pump or dry sump system is the venturi effect and the pressure present in the crankcase. Whether you route it to your exhaust or your intake, you are still trying to use the venturi effect to draw gases out faster than the pressure would push them out anyway. There is never any "vacuum" in your intake tube or your exhaust.

And unless you have a very well-baffled valve cover, you'll probably be sucking out some oil mist along with the crankcase gases, so you'll need a catch can to catch them, at least if you're running it to your intake tube. If you're running it to your exhaust, it really won't matter much except that it might smell bad from burning said oil mist.

The exhaust evac route is arguably more effective at high rpm, as the gases in the exhaust tube are moving faster and therefore generate a stronger venturi effect, you'll just need a one-way check valve so you aren't blowing exhaust into your engine at low engine speeds.

You can and should mount one of these in your exhaust or stainless intake tube for maximum effectiveness:

The tube should be turned 180 degrees to get maximum vacuum. Then you'd see static pressure (aka venturi effect) PLUS the negative component of the dynamic pressure.

This is exactly how steam ejectors work in altitude chambers. Blow a ton of steam down a huge ass pipe, and then have a tube from the chamber facing downstream of the steam ejectors. Will pull to almost a perfect vacuum if ya got enough ballz in your steam system.

Having it facing the upstream way is stupid because you get the POSITIVE component of the dynamic pressure (i.e. sticking your hand out the window and feeling the air push your hand back).

PoorMans180SX · 12-19-2014, 12:52 PM

Quote:

Originally Posted by Def

The tube should be turned 180 degrees to get maximum vacuum. Then you'd see static pressure (aka venturi effect) PLUS the negative component of the dynamic pressure.

This is exactly how steam ejectors work in altitude chambers. Blow a ton of steam down a huge ass pipe, and then have a tube from the chamber facing downstream of the steam ejectors. Will pull to almost a perfect vacuum if ya got enough ballz in your steam system.

Having it facing the upstream way is stupid because you get the POSITIVE component of the dynamic pressure (i.e. sticking your hand out the window and feeling the air push your hand back).

Thank you for that tidbit, I never knew that. I'll make sure and run mine "backwards" when I build it in a few weeks.

feito · 12-19-2014, 01:00 PM

Quote:

Originally Posted by Def

Given that the damn thing forms a loop around the engine and doesn't go anywhere (not much evacuation there).

What do you mean "much"?.....

quickdiversion · 12-19-2014, 01:07 PM

I'll help out with a visual reference.
Here is my setup.

*TheRealSy90* · 12-19-2014, 01:15 PM

Ooh I want ls coil packs so bad haha. And yep that's pretty much the setup I was considering, although I would run the back fitting to the crank case, and run the fitting on the side to the exhaust valve, opposite of what you have.

quickdiversion · 12-19-2014, 01:22 PM

Quote:

Originally Posted by TheRealSy90

Ooh I want ls coil packs so bad haha. And yep that's pretty much the setup I was considering, although I would run the back fitting to the crank case, and run the fitting on the side to the exhaust valve, opposite of what you have.

LS2 coils are simple to set up and wire, you pull the signal from the line into the ignitor from the stock coils and the ground from there to ecu ground on the coils. Chassis ground from the other. That 12v that's the general idea.

As for your idea of running them in reverse, you might be able to, but with a top mount setup, space is limited as to where these lines can be run. Plus I am not sure how effective it will be as crankcase scavenging, like drawn out in the long explanation in the link, is mainly for high rpm and WOT use. plus with the direction of the baffling I am not sure how it would all go as It have been a while since I removed the valve cover and looked at it all.

Maybe someone that has played around with it more than I can comment on that.

12-18-2014, 11:34 AM	#489
Def Post Whore! Join Date: Apr 2004 Location: Houston, TX Posts: 2,701 Trader Rating: (16) Feedback Score: 16 reviews	Seriously... that's horrible. __________________ S13 Hatch - Goes around tracks quickly DEFSPORT

12-18-2014, 04:11 PM	#499
jr_ss Post Whore! Join Date: Dec 2005 Location: Pa Posts: 6,052 Trader Rating: (34) Feedback Score: 34 reviews	Exhaust venturis create vacuum under all conditions, not just at idle. __________________ My SR20VET

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12-13-2014, 01:12 AM	#486
Dboyizmlg Nissanaholic! Join Date: Aug 2011 Location: SoCal (I.E.), San Berdino, Colton, Redlands Posts: 1,665 Trader Rating: (17) Feedback Score: 17 reviews	^ I was thinking the same thing.

12-18-2014, 02:22 PM	#493
blackmags91 Zilvia Member Join Date: Sep 2010 Location: Phoenix, AZ Posts: 225 Trader Rating: (1) Feedback Score: 1 reviews	I read the first two pages, im not gonna read the next 15, especially while im at work haha.. so pardon me if this has been brought up already, but what is the issue with the OE oil/air separator? Why does everyone hate it? (I dont think it's THAT ugly..) I bought my current SR without one and one of the first things that I did was find another one and reinstall it. Nissan wanted it there, its supposed to be there.. So why not? I also have a greddy catch can between the "T" and the turbo intake that never fills up even on the hardest of track days. Ive had kids at local meets and shit laugh and ask why I have the separator and a catch can, but tbh I dont deal with ignorant kids wearing flatbilled Hoonigan snapbacks that barely have their GED. So please, can someone that's educated convince me to remove the factory separator.

12-19-2014, 10:10 AM	#500
blo0d Zilvia Member Join Date: Jan 2011 Location: JAMAICA Posts: 206 Trader Rating: (1) Feedback Score: 1 reviews	@slider2828 what about the newer flat nissan valve covers, how good are they? do they still need this type of modification on RWD? This thread on the dash forums suggest these VC's are "improved" (post #2) http://www.sr20-forum.com/informatio...d-edition.html http://www.sr20-forum.com/informatio...d-edition.html

12-19-2014, 01:07 PM	#508
quickdiversion Zilvia Junkie Join Date: Aug 2012 Location: nj Age: 38 Posts: 341 Trader Rating: (4) Feedback Score: 4 reviews	I'll help out with a visual reference. Here is my setup.