fperra

Does anyone have any experience with the KrankVent? I've just installed a pair on my turbo S. If nothing else, it's good insurance against pressurising the lower end of the engine through a sticking PCV valve. At best, if it works as advertised, it may be good for a 3 to 5 % HP boost. Check it out at http://www.krankvent.com

Nobody

Does this have the same effect as venting the crankcase to a K&N?

AndyS2

Isnt 5% a little too much gain. It correspondes to like 12hp on a stock and about 20-30 hp on a modded S.

fperra

No. It creates a partial vacuum in the crank area and that is where the added HP is suppose to come from. Visit their web page; they have a good write-up on how it works. It was originally designed for drag bikes.

fperra

All those with intercoolers/aftercoolers should look into this. It will prevent oil from collectiong inside your intercooler and destroying the heat transfer capabilities.

Gernby

I read the tech info. I think the HP increase is a far fetch. HP shouldn't be effected by positive pressure any more than it is vaccuum. Positive pressure would resist on the down stroke, and assist with the up stroke. Vaccuum would resist on the up stroke, and assist in the down stroke. What's that saying "6 in one, half-dozen in the other"?

fperra

The system was originally designed for drag race Harley engines. I believe on a Harley, both con rods are connected to the same journal on the crank - both pistons go down at the same time. That is what gives them their unique sound, and that is why it works so well on those engines. Why it works on an engine where the up moving piston is balanced (speaking of crank pressure) by the down moving piston, I don't know, but a lot of people use them in high performance cars and swear by them. What I can see is that the when the intake manifold in a vacuum condition, this will be transferred to the crank case, which is a good thing. Under a boosted condition, the one way check valve will prevent the crank from being pressurized. The PCV valve, in theory, should prevent this, but they are not the fastest responding devices and they are prone to failure. Imagine if the PCV valve stuck open under boosted conditions such as 6 or 7 psi. That pressure is going straight into the crank case and working against the power stroke. Some of the pressure will be released through the forward vent on the valve cover that feeds into the intake piping right after the air cleaner, bringing along with it a lot of oil which will condense and contaminate the inside of the intercooler/aftercooler. This is a well documented problem with turbocharged Supras. For about $100, the KrankVent is good insurance if nothing else.

Gernby

Why not just put a breather on the front of the valve cover? Even if the PCV valve fails, the breather will flow more volume than the PCV will. The only difference in performance I can see from having vacuum over having pressure is that the pistons will be moving less dense air around in the crank case.

fperra

Well Gernby, all I can say is that a lot of people swear by it, including Farrari and Porsche owners. Here are a few testimonies:

http://www.durable1.com/crank_vent.htm

http://www.stealth316.com/2-krankvents.htm

http://www.3si.org/portal/forums/showthrea...ts&pagenumber=1


Next time I dyno, I'll try with and without. But even if there are no HP benefits, which I doubt, there will be reliability benefits.

GaryRudolph

I'm a little confused... From my understanding the PCV should flow out into the intake manifold, and the air inlet on the front of the valve cover should flow in. But... the KrankVent instructions say differently.

They are claming that the air inlet on the front of the valve cover should flow out?!?



Does this make sense? The issue is what direction should the KrankVent flow be on the air inlet on the front of the valve cover.