Relieving Crank Pressure
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Relieving Crank Pressure My set-up is: removed all lines running to and from the valve covers/intake/throttle body, plugged them, and put valve cover breathers on the driver and passenger valve covers. This should net as much ventilated crank pressure as possible correct?
Before my engine blew up, I had oil frothing in my oil filler neck. I didn't pay any attention to it and chalked it off as condensation. Then on the dyno, I noticed oil misting out of my pass. valve cover breather under boost.This was with the log style TTi kit and 11.5 lbs of boost/stock engine.
The engine blew on the dyno about 15 pulls later, ringland #7. Was the engine already damaged or is my breather system wrong and the engine blowing just a coincidence? I am having a new engine with forged internals put in my car in about a week so I want to make sure it is ok.
I plan on hooking up the kit and tuning it for street driving without getting into any boost for the first 500 miles. Then I will tune it for WOT and see what happens. I plan on running about 15lbs of boost or 600rwhp (you need 15lbs on this kit to make that much power.) Think I am ok? Do I need to do anything to my PCV system?
Before my engine blew up, I had oil frothing in my oil filler neck. I didn't pay any attention to it and chalked it off as condensation. Then on the dyno, I noticed oil misting out of my pass. valve cover breather under boost.This was with the log style TTi kit and 11.5 lbs of boost/stock engine.
The engine blew on the dyno about 15 pulls later, ringland #7. Was the engine already damaged or is my breather system wrong and the engine blowing just a coincidence? I am having a new engine with forged internals put in my car in about a week so I want to make sure it is ok.
I plan on hooking up the kit and tuning it for street driving without getting into any boost for the first 500 miles. Then I will tune it for WOT and see what happens. I plan on running about 15lbs of boost or 600rwhp (you need 15lbs on this kit to make that much power.) Think I am ok? Do I need to do anything to my PCV system?
11.5 boost and stock engine. I think that sums it up. Allot of the later LS1 motors have loose ring problems to begin with, I think there might even be info about it on the web. Add FI to that and you get lots of blowby and thats probably why you saw PCV issues. Going with two breathers gets you halfway there, you also want to put a little vaccum in the equation. The LS6 valley cover works good for this, there is a 3/8 tube in the front that on Z06 cars goes to the nipple on the intake. You can also run it right to the inlet nipple on your turbo. A bunch of us do this, some put a catchcan somewhere inline but dont use one with a vent or you will lose vaccum at the can and it wont work. I run this setup and no oil ever comes out of my breathers, also a little vaccum at WOT in the case can ensure good ring seal. Lastly for all the TTI street kit guys the big reason you have oil drain problems from the turbo is because the case is usually pressurized and wont allow the oil to come back in because its only a gravity feed. How many times have you heard this in a post "Everytime I get on it hard it makes a smoke cloud behind the car" Oil just backs up and gets pulled through the bearing seals in the turbo, this can also lead to premature seal failure.
As far as the engine blowing, stock pistons just dont like 11.5 pound boost and everything that comes with that, mine broke at 10# on a good tune, they just dont hold up well.
As far as the engine blowing, stock pistons just dont like 11.5 pound boost and everything that comes with that, mine broke at 10# on a good tune, they just dont hold up well.
I also run a -8 hose to a K&N directly from the front of the oil pan up to the radiator support. This lets the crankcase breath without having to travel back up through the heads to get vented. Between that and 2 breathers per valve cover, I finally got a handle on crankcase pressure. Even now I get a little dribbling out the pass. side front vent after a hard run.
Jim
Jim
Originally Posted by libertine1015
11.5 boost and stock engine. I think that sums it up. Allot of the later LS1 motors have loose ring problems to begin with, I think there might even be info about it on the web. Add FI to that and you get lots of blowby and thats probably why you saw PCV issues. Going with two breathers gets you halfway there, you also want to put a little vaccum in the equation. The LS6 valley cover works good for this, there is a 3/8 tube in the front that on Z06 cars goes to the nipple on the intake. You can also run it right to the inlet nipple on your turbo. A bunch of us do this, some put a catchcan somewhere inline but dont use one with a vent or you will lose vaccum at the can and it wont work. I run this setup and no oil ever comes out of my breathers, also a little vaccum at WOT in the case can ensure good ring seal. Lastly for all the TTI street kit guys the big reason you have oil drain problems from the turbo is because the case is usually pressurized and wont allow the oil to come back in because its only a gravity feed. How many times have you heard this in a post "Everytime I get on it hard it makes a smoke cloud behind the car" Oil just backs up and gets pulled through the bearing seals in the turbo, this can also lead to premature seal failure.
As far as the engine blowing, stock pistons just dont like 11.5 pound boost and everything that comes with that, mine broke at 10# on a good tune, they just dont hold up well.
As far as the engine blowing, stock pistons just dont like 11.5 pound boost and everything that comes with that, mine broke at 10# on a good tune, they just dont hold up well.
Originally Posted by DeltaT
I also run a -8 hose to a K&N directly from the front of the oil pan up to the radiator support. This lets the crankcase breath without having to travel back up through the heads to get vented. Between that and 2 breathers per valve cover, I finally got a handle on crankcase pressure. Even now I get a little dribbling out the pass. side front vent after a hard run.
Jim
Jim
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From: Louisville, Ky
So you recommend changing over to the LS6 valley pan and running the tube off that into the intake manifold? And this will also create a vacuum which helps in what way? I know you said it ensures better ring seal, how is that? If I do this without the catch can, will there be oil mist going back into my intake manifold? Can this potentially harm anything. I really appreciate the advice.
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Verdad Gallardo No, run the hose from the LS6 valley cover to the inlet side of your turbo, on some turbos there is a nipple in place, some people run it into the rubber inlet hat also with some combination of a barbed connector. Mine has a nipple on the turbo inlet so thats what I did. Case by case basis depending on your setup. The vaccum pulls the excess pressurized air built up in the crank case, as far as oil mist or contamination goes you should not be getting more than you would with the stock PCV system which does the same thing. You are already burning off contamination through the engine in this manner right from the factory. Remember when you have blowby you are also getting fuel and a small amount of spent gasses in your oil from the cylinder. Why does vacuum increase ring seal? I dont know, I am an interiors engineer so I cant answer that but Im sure someone here can. It is however a known and undisputed fact in motorsports.
This method does not pull oil from the crankcase but will pull any particles that are in the pressurized gasses thats why some guys like to run a catch can in conjunction with this method. I will probably add one this winter although I have had no problems without one. I pull at the turbo inlet so to check for trouble I took my MAF off and looked at it and it doesnt have anything on the screen or sensors and is very clean so I have no worries, Im only adding a catch can to keep any oil or contaminents from building up in the intercooler.
This method does not pull oil from the crankcase but will pull any particles that are in the pressurized gasses thats why some guys like to run a catch can in conjunction with this method. I will probably add one this winter although I have had no problems without one. I pull at the turbo inlet so to check for trouble I took my MAF off and looked at it and it doesnt have anything on the screen or sensors and is very clean so I have no worries, Im only adding a catch can to keep any oil or contaminents from building up in the intercooler.
Pix as requested:
Upper Shot (obviously not an LSx):
Shot from underneath:
The oil pan breather really took a load off the top end breathers, since it is venting pressure closer to the source. It does not blow any oil, since when I am accelerating, the crankcase pressure is highest, but the oil is all at the back of the pan!
Jim
Upper Shot (obviously not an LSx):
Shot from underneath:
The oil pan breather really took a load off the top end breathers, since it is venting pressure closer to the source. It does not blow any oil, since when I am accelerating, the crankcase pressure is highest, but the oil is all at the back of the pan!
Jim
