HYDRODYNAMIC
Rock Stacker
So to start this off: Fuel Air Trap System or FATS is known within our sport and fairly well accepted by all as a way to prevent fluid from leaking from an object during rollover. The simple way I have read is four sides and down. Theory is plumb from the top then around the four sides somewhat parallel to the ground but with slope so the liquid will run back into the container, then lastly down past the container. Any way you roll the container the line will always be higher and prevent fluid from running out. SEE Fuel cell picture swiped from BillaVista. FATS applies to fuel tanks, engine crank cases, transmissions, power steering reservoirs, transfer cases, axles, and more.
I started researching engine venting which is greatly debated both on and off road. On road people do not care about FATS but do debate between venting to atmosphere or running back to the intake with a PCV system. Theories are that positively venting and removing the blow by and acidic gases provides cleaner oil and better ring seal. Theories also say that you do not want to pull oil vapor or actual oil and gum up the pistons and top end of the motor or hydro-lock if you suck up oil from the valve covers or pool it in the intake and pull in a glob. Some have proved that today's oils have no issue absorbing and cleaning the crank case gases. Another theory is vacuum is beneficial, race engines can add power by adding a vacuum pump. Running a vacuum pump on a normal engine is advise against by some engine builders, I believe it has to do with the rings. If you are wide open throttle on a normal engine you are probably not going to be running enough vacuum for the PCV system to function unless you are running a pump. Applications also come into play, as a car in traffic idling or cold short trips could benefit from ventilation vs a engine that is working hard all day long.
I researched regarding a gen IV 2010 6.0. The factory PCV system => The intake pulls dirty air from one valve cover which is connected to the crank case and the other valve cover pulls clean air after the MAF and before the throttle body and dumps that into the crank case.
While GM was road and track testing they found that the oil was getting picked up from the valve covers and burning a lot of oil. The LS2 and LS7 had a new crank valley cover designed with a center pickup for the PCV system. It has what I have only heard to be a baffle system to prevent oil vapor and liquid from being picked up. Most inportantly for FATS routing is that the pickup is top and center as far away from oil as possible. The differences between the LS2 and the LS7 covers is the hose barb on the LS2 and the QD tube on the LS7 cover. Also shown below is the baffled LS6 valley cover with the knock sensor locations.
So my plan so far is to run a 1/2" vent line off the LS7 valley cover and go around the engine and down with a 1/2" hose and filter on the end to keep out dust. I might try 1/2" hard line as well since it will look cleaner and be safer for fire resistance. The intake and the valve covers will all be capped.
I have heard some say that the single line is not enough and that the blow by will pop the dip stick out or causing leaking from the seals. I have also heard that if this is the case then your rings are short and a PCV system is not going to help especially at WOT with no vacuum.
What is everyone else doing?
I started researching engine venting which is greatly debated both on and off road. On road people do not care about FATS but do debate between venting to atmosphere or running back to the intake with a PCV system. Theories are that positively venting and removing the blow by and acidic gases provides cleaner oil and better ring seal. Theories also say that you do not want to pull oil vapor or actual oil and gum up the pistons and top end of the motor or hydro-lock if you suck up oil from the valve covers or pool it in the intake and pull in a glob. Some have proved that today's oils have no issue absorbing and cleaning the crank case gases. Another theory is vacuum is beneficial, race engines can add power by adding a vacuum pump. Running a vacuum pump on a normal engine is advise against by some engine builders, I believe it has to do with the rings. If you are wide open throttle on a normal engine you are probably not going to be running enough vacuum for the PCV system to function unless you are running a pump. Applications also come into play, as a car in traffic idling or cold short trips could benefit from ventilation vs a engine that is working hard all day long.
I researched regarding a gen IV 2010 6.0. The factory PCV system => The intake pulls dirty air from one valve cover which is connected to the crank case and the other valve cover pulls clean air after the MAF and before the throttle body and dumps that into the crank case.
While GM was road and track testing they found that the oil was getting picked up from the valve covers and burning a lot of oil. The LS2 and LS7 had a new crank valley cover designed with a center pickup for the PCV system. It has what I have only heard to be a baffle system to prevent oil vapor and liquid from being picked up. Most inportantly for FATS routing is that the pickup is top and center as far away from oil as possible. The differences between the LS2 and the LS7 covers is the hose barb on the LS2 and the QD tube on the LS7 cover. Also shown below is the baffled LS6 valley cover with the knock sensor locations.
So my plan so far is to run a 1/2" vent line off the LS7 valley cover and go around the engine and down with a 1/2" hose and filter on the end to keep out dust. I might try 1/2" hard line as well since it will look cleaner and be safer for fire resistance. The intake and the valve covers will all be capped.
I have heard some say that the single line is not enough and that the blow by will pop the dip stick out or causing leaking from the seals. I have also heard that if this is the case then your rings are short and a PCV system is not going to help especially at WOT with no vacuum.
What is everyone else doing?
Last edited:
