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Crank case vent Mod

7K views 9 replies 6 participants last post by  Zack92 
#1 ·
in a lot of other forums about cars/trucks...I always see mods on crank case vent , so I decided to try one on my sentra. for those of you who have never heard of this...the theory is that the crank case on most vehicles today are routed back into the air box so that the engine can re-burn this oily, hot air. a lot of people seem to think that putting oily ,hot air back into the engine is not a great idea and it is mainly done by manufacturer's for emissions purposes. a lot of people believe that this air can cause loss in power and fuel mileage...plus could, over time, add sludge to the upper valve train area.
So, with that idea in mind....I looked at the set up by Nissan and made my own crank case mod. i'll keep my eye on it and let everyone know if there are any pro's and con's on this mod....
 
#3 ·
I did the air breather on my wife's 2010 Nissan Armada...its more of a pain. you have to check it periodically.....and even though it did collect some oil....I'm not sure it was worth the extra cost. I think I paid over $50 bucks for a cheap kit....and I only paid $4.50 for the breather for the sentra and I had the 3/4" vacuum cap in my tool box
 
#4 ·
Ahhh ok. I think it would be cool to see the results of engines with and without breather mods or catch cans. Like after 50k miles what the insides look like on an engine with a breather/catch can and then the same engine without the mod. Just to see what the oil blow-by does to the internals.
 
#5 · (Edited)
My concern about breather filters is that there will be no active negative pressure to suck/ventilate the crank case.

I remember reading an article that in the early days, car manufacturers would put the crankcase vent to somewhere near an outside body panel where there is ample air flow so that ram effect will create negative pressure in the vent opening to pull out crank air. Then they thought that it would be more efficient to make use the vacuum created by the air intake itself. So I think if the crankcase ventilation was designed to be mated with the air intake, disconnecting the system will have a negative effect on oil life (unless we ram effect in the breather filter).

With my old 96' sentra, the crankcase ventilation tube have a separate filter in the air box (and that's even before the separate main air filter). So I'm sure the air is almost always clean before entering the intake manifolds. I don't know why our present car has the ventilation tube connected directly near the throttle body, bypassing the air filter.:smack: No filter of any kind to stop some occasional oil splurge??? If that is the case, I think, a filter with catch bucket may be warranted.

Edit: I just checked my engine bay, and noticed there's a fatter tube connecting the breather tube to the main air intake tube just before the throttle body. I really hope that there is some kind of filter inside it. I tried to loosen the clamp holding it but it is still tight so I hadn't checked it. ;p
 
#6 · (Edited)
The hole you plugged is before the throttle so no vacuum. that is filtered air. So all you did is add a filter to a hose that allready was sucking filtered air! I would leave it the way it was. However if you do not want your engine sucking on the crank case leave what you have done and find the screw in pcv valve passenger side top valve cover it goes to a vacuum port this is still sucking your crank air. Plug both ports. But like I said I would leave it stock. Note the vapors inside your engine water and gases from combustion need a way out the more the better the gummy varnish that if forms will make your rings stick causing loss of power and oil consumption and smoke .
 
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