S2000 Forced Induction S2000 Turbocharging and S2000 supercharging, for that extra kick.

Boost into the crankcase is bad

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Old 06-09-2006, 11:25 AM
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Actually, the front vent on the s2000 valve cover(or any car for that matter that has a pcv system) is the source of "fresh" air when the contaminated air is sucked through the pcv area. Check out these links:

http://www.advanceautoparts.com/english/yo...20050101pv.html

http://autorepair.about.com/cs/gener.../bldef_621.htm

"PCV is an acronym for positive crankcase ventilation. A PCV valve is only half of a two-part system. At one end of the system is a breather, which allows fresh air into the crankcase"

"Besides totally eliminating crankcase emissions as a source of air pollution, the constant recirculation of air through the crankcase helps remove moisture which otherwise would cause sludge to form. Thus the PCV valve extends the life of the oil and engine."


Old 06-09-2006, 01:21 PM
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IS this correct
Old 06-09-2006, 02:18 PM
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Yep, away from the valve cover.
Old 06-09-2006, 09:22 PM
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Originally Posted by gary_phd,Jun 9 2006, 07:30 AM
I "introduced" the Kranvents to Comptech. I had some issues with my blower, and brought my car to their facility. In the process of trying to diagnose the issue, they tested the amount of pressure in the blower and crankcase with and without my Krankvents installed. What they found was that boost was entering the crankcase, and by the third run dyno run, I was getting FULL boost in the crankcase and blower. Mind you, the pcv on my car only had 5000 mile on it. I installed the Krankvents almost immediately after installing my SC (@5000 mi).

Without the Krankvent system, I achieved only ~ 270 ish whp (can't remember off hand). This was when boost was bypassing the pcv. With just the Krankvent at the PCV, ~ 285 whp. Then, with both installed at the pcv and breather, I hit 305 whp.

Aside from the power gains, you do not want any boost inside the blower because of the design of the gaskets (inner and outer) at the shaft. This increases the chance of the gaskets blowing, and eventually leaking.

As a result, they opined that the AP2 pcv design may be weaker, and that they were going to recommend the Krankvents - at least to one at the pcv - to prevent boost from entering the crankcase.

I've got over 36k on my car, SC installed around 5k, with Krankvents installed around 5500k.
So, then the optimum setup would be to install two of the mini kits correct?
Old 06-09-2006, 10:05 PM
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Originally Posted by Harpoon,Jun 10 2006, 12:22 AM
So, then the optimum setup would be to install two of the mini kits correct?
Each mini-kit comes with two krank vents, one for the PCV valve and one for the breather at the front of the valve cover. You only need one set.
Old 06-10-2006, 12:56 AM
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I just ordered that kit, because my dip stick pops out a bit time to time.

Now my question is:

If I run turbo and not SC and I removed the secondary vacuum system since the AEM EMS does not support it, do I need to put something on the front breather as well? I run it nacked open for over a year, just wanted to put a small filter on it. Boost can not get in my crank case trough it anyway, since NOTHING is connected to it. Only problem might be sand entering that nacked whole right?

And one more time the stupid tripple check question...

Boost should not come FRom the intake manifold through the PCV INTO the crank case, so I will install it in a way where it flows only FROM the engine, INTO the manifold, but blocks the flow the other way around, correct?

Thanks in advance...haven't been here for a while and this got me paranoid BIG time....
Old 06-10-2006, 06:03 AM
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Jakub, I have the same thing on my car. I have just a small k&n type filter on the front of the valve cover.

In this case to block the boost from entering the crank case via the pcv valve couldn't I just put another small filter in place of the pcv valve and cap off the niple on the manifold?
Old 06-10-2006, 08:25 PM
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Here's the schematic of the PCV system on the stock S:

As you can see, that front breather flows "fresh" air into the valve cover. Putting a crankvent there would prevent this from happening. Would there be any ill-effects from doing this?
Old 06-11-2006, 12:41 AM
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I don't belive XViper is asking something?OMG! :-))))))))))))))))
Old 06-11-2006, 08:16 AM
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Correct me if I'm wrong, but the PCV system is strictly an emissions related component, and really isn't truly necessary. It's to keep any blowby into the manifold to be combusted, which otherwise would just be released into the atmosphere.

However, if you really wanted, you can eliminate the pcv and run open elements at the breather and pcv side. If you remove the pcv, blowby / fumes will come out through the front and rear openings. Originally, the blowby was just allowed to vent into the atmosphere - which the feds didn't want, and hence the creation of the recirculating system.

It's the pressure build up that you need to worry about, which could damage your engine. If you use the two Krankents, you don't have to worry about pressure build up.

How about the possible "sludge" that'll stay because you only have vacuum conditions? Well, you still get a good amount of flow regardless, as it's only a slight vacuum, and you still get gasses passing the piston rings. The "fresh air" or breather component is set up this way so that flow only goes in one direction - into the intake manifold. You don't need the "fresh air" as you get positive pressure already, which is created by the blowby gases. The vacuum condition of part throttle and idle pulls these back into the intake manifold. If you put an oil catch can in line, you don't have to worry about sludging up your intake manifold.

Kranvent at the pcv:


Inline catch can:


Accumulated blowby:



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