More Oil Catch Can Contents
#21
I'm extremely interested in this as well. I've been going back and forth about what to do about my catch can setup.
Could one just run the 2 VC breather ports to a tee, and the 3rd line off the tee to the exhaust, eliminating the catch can all-together?
Could one just run the 2 VC breather ports to a tee, and the 3rd line off the tee to the exhaust, eliminating the catch can all-together?
Last edited by mighty mouse; 01-27-2011 at 09:02 PM.
#22
Its actually an aerodynamic effect more then a ring seal effect. The amount of pressure in the cylinder is over a 100 times higher then the few pounds of - pressure created by the vacuum.
By reducing the pressure in the crank case reduces this reduces the air density in the crank case. So following from aerodynamic drag density is a proportional scalar of this drag. So if you reduce the pressure in the crank case to 20% of normal, then aerodyanmic drag will be 20% of what is normally experienced.
This system combined with crank scrapers could do an excellent job to improve efficiency and get extra horsepower out of the engine.
I don't see any problem with the system from a reliability standpoint either as the intake manifold regularly pulls the crank case pressure down, this just does it on a larger scale and at loads that matter as far as horsepower is concerned. The actual effect seen here is the bournulli effect.
http://en.wikipedia.org/wiki/Bernoulli_effect
Using the equations here you could probably round about estimate an optimal pipe size to exhaust flow velocity to get suction sucking.
By reducing the pressure in the crank case reduces this reduces the air density in the crank case. So following from aerodynamic drag density is a proportional scalar of this drag. So if you reduce the pressure in the crank case to 20% of normal, then aerodyanmic drag will be 20% of what is normally experienced.
This system combined with crank scrapers could do an excellent job to improve efficiency and get extra horsepower out of the engine.
I don't see any problem with the system from a reliability standpoint either as the intake manifold regularly pulls the crank case pressure down, this just does it on a larger scale and at loads that matter as far as horsepower is concerned. The actual effect seen here is the bournulli effect.
http://en.wikipedia.org/wiki/Bernoulli_effect
Using the equations here you could probably round about estimate an optimal pipe size to exhaust flow velocity to get suction sucking.
#23
I'd considered this way back, but from what I understood the tube needed to be located near the beginning of the exhaust system to generate good vacuum. That meant ahead of the cat, which is out of the question for those who have emissions (and maintain that standard annually).
And I don’t understand why it would make much difference where along the exhaust system you put it as long as you didn’t put it in before a restriction. The exhaust flow has the same mass flow rate along the entire distance it losses a small amount of velocity as it cools but it can't be much.
Bob
#26
Bob
#27
Elite Member
Thread Starter
iTrader: (2)
Join Date: Jan 2009
Location: Columbus, OH
Posts: 4,140
Total Cats: 229
I'm worried about the ability of the cat to pass the expelled contents of the crankcase without eating itself apart. I don't plan to pass emissions testing, but the cat is staying in. This is a 99.9% street car, I care at least some for emissions components - enough to not run a crankcase vent to the exhaust if it means removing the cat.
#28
I’m actually thinking of putting the slash tube in my test pipe where the cat would be and have the components so I could quickly convert my catch tank system into a PCV emissions legal closed system.
Bob
#29
I'm worried about the ability of the cat to pass the expelled contents of the crankcase without eating itself apart. I don't plan to pass emissions testing, but the cat is staying in. This is a 99.9% street car, I care at least some for emissions components - enough to not run a crankcase vent to the exhaust if it means removing the cat.
Bob
#30
Elite Member
Thread Starter
iTrader: (2)
Join Date: Jan 2009
Location: Columbus, OH
Posts: 4,140
Total Cats: 229
Divided into subcomponents - these are 2oz (to the rim of the glass) shot glasses.
The middle third doesn't subdivide very readily, and I don't have a centrifuge, so that's as fine of detail as I'm going to get.
Enjoy!
The middle third adheres to the glass, which further increases the difficulty of separating it. You can see where it has adhered to the water glass on the right during separation.
The middle third doesn't subdivide very readily, and I don't have a centrifuge, so that's as fine of detail as I'm going to get.
Enjoy!
The middle third adheres to the glass, which further increases the difficulty of separating it. You can see where it has adhered to the water glass on the right during separation.
#33
Moderator
iTrader: (12)
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 20,645
Total Cats: 3,009
I've been using one of the Summit slash cut/check valve evacuation kits on my old GTO for years. It works well in the header collector. If you drop the breather hose in a gallon jug of water it will suck it dry in just a couple of good jabs on the throttle. You will want to disconnect it if you put your car on a dyno because it will cause the tailpipe o2 sniffer to read incorrectly. And it is better to use it in conjunction with a catch can so that all of that oil doesn't end up in your exhaust (makes a little smoke).
#34
Elite Member
iTrader: (2)
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,682
Total Cats: 130
Yeah I"ve told others about using the exhaust to create a vacuum in the crankcase, people call me crazy, finally good to see others thinking about doing it.
By null at 2010-11-13
you can see the o2 sensor and underneath is the tube with slashcut and a one way check valve. That is my downpipe.
I don't see why not to do it, gains you some power, puts a vacuum on the rings and you don't have to suck stuff though the intake to create that vacuum.
By null at 2010-11-13
you can see the o2 sensor and underneath is the tube with slashcut and a one way check valve. That is my downpipe.
I don't see why not to do it, gains you some power, puts a vacuum on the rings and you don't have to suck stuff though the intake to create that vacuum.
#35
Elite Member
iTrader: (2)
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,682
Total Cats: 130
I don’t think it would be good to eliminate the catch can it is needed to separate some oil. I've never been able to keep lots of liquid oil from filling up my catch can due to certain cornering/acceleration conditions I seem to see on a lot of tracks. Never a problem on the street though. I don’t mind some blow by going out the tail pipe but I think dumping a cup of oil out in the exhaust every so often would look sort of bad.
Bob
Bob
Valve cover only routed to catch can
catch can VTA
and
catch can also routed to exhaust slash cut.
Or is the VTA in the catch can not necessary?
#36
Divided into subcomponents - these are 2oz (to the rim of the glass) shot glasses.
The middle third doesn't subdivide very readily, and I don't have a centrifuge, so that's as fine of detail as I'm going to get.
Enjoy!
The middle third adheres to the glass, which further increases the difficulty of separating it. You can see where it has adhered to the water glass on the right during separation.
The middle third doesn't subdivide very readily, and I don't have a centrifuge, so that's as fine of detail as I'm going to get.
Enjoy!
The middle third adheres to the glass, which further increases the difficulty of separating it. You can see where it has adhered to the water glass on the right during separation.
#38
Elite Member
iTrader: (2)
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,682
Total Cats: 130
Also, if one had a restrictive exhaust, this wouldn't work as well.
I found a one way valve at summit:
http://www.jegs.com/i/JEGS-Performan...93#moreDetails
It would be nice to find one with threads so I could run AN fittings and braided line instead of something that will wear out.
#40
I know the stock crankcase ventilation system is inadequate for boosted application. I know a lot of us have tried ways to increase ventilation port size, but that success has been limited at best. Has anyone actually found a viable way to increase port size in the valve cover?
Perhaps more importantly, has anyone found a way to tap directly into the crankcase to relieve this pressure instead of forcing it through the smallish oil drain passages through the block and head?