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Nobody does but you could. The idea of a pump is not to just relieve pressure but to put the crankcase under constant vacuum. After learning what a cluster the stock PCV is I wonder if a pump would not work very well on an LSJ in the AC compressor or tensioner location. More weight vs a few hp. More complex vs stupid simple. This is all out race stuff but since dabbling in that is what we do..... Tech: How External Vacuum Pumps Free Up Horsepower - EngineLabs
electric vacuum pumps are becoming more common to pull contamination from the angine and keep negative pressure on the crank case
What are you saying here exactly? Are you talking about the tube from valve cover to intake?
correct it pulls vacuum wot from that location the check valve in the intake manifold meters in both directions to keep negative pressure on the crank case and to remove contamination
There should be a slight vacuum from air filter and general restriction in the intake tract but it shouldn't be much. However the absolute pressure has to be less than atmospheric or air wouldn't be sucked in.
There should be a slight vacuum from air filter restriction in the intake tract but it shouldn't be much. However it has to be less than atmospheric or air wouldn't be sucked in.
Pulls vacuum or creates vacuum. That would be referred to venturi or ported vacuum which is usually less than 1 inch of mercury. About 15" less than what is needed to evacuate a crankcase.
Pulls vacuum or creates vacuum. That would be referred to venturi or ported vacuum which is usually less than 1 inch of mercury. About 15" less than what is needed to evacuate a crankcase.
Originally Posted by HGT
Depends how plugged or inferior the air filter is. Always under 1" with a good air filter. It takes a water manometer to measure it.
it takes a lot more then an inch of mercury to keep the dipstick in place
Ok... I have been a GM Field Engineer since March of 1980... You will have to explain this one to me and I am sure others. Besides the interference double o-ring fit there is also gravity. So when you shut your engine off your dip stick just starts to levitate out of the tube?
If your blowing your dip stick out of an OEM production vehicle you have a defective stick, tube or too much crankcase pressure building up. And even on a high boost engine you have an issue as you are not properly evacuating the crankcase for the build. Then there are those that put a blower on their 2.4's and 2.2's that blocked off the PCV system wondering what went wrong.
Ok... I have been a GM Field Engineer since March of 1980... You will have to explain this one to me and I am sure others. Besides the interference double o-ring fit there is also gravity. So when you shut your engine off your dip stick just starts to levitate out of the tube?
If your blowing your dip stick out of an OEM production vehicle you have a defective stick, tube or too much crankcase pressure building up. And even on a high boost engine you have an issue as you are not properly evacuating the crankcase for the build. Then there are those that put a blower on their 2.4's and 2.2's that blocked off the PCV system wondering what went wrong.
I think what MrB. is trying to say is there is a certain amount of vacuum required to prevent crank case pressure from building to the point it will pop your dipstick. Not saying he is right or wrong just trying to interpret what he meant. Obviously it doesn't need crankcase vacuum to stay in or the dipstick would pop out just sitting there with the engine off.
Obviously it doesn't need crankcase vacuum to stay in or the dipstick would pop out just sitting there with the engine off.
That is my point but that is not what he is saying. I believe there are a lot of members here that don't quite understand vacuum, atmospheric pressure and boost, little lone what goes on in the crank case. At WOT all naturally aspirated engines drop to zero or near zero engine vacuum. Around 7" H2O or less. Their dip sticks do no come out.
Ok... I have been a GM Field Engineer since March of 1980... You will have to explain this one to me and I am sure others. Besides the interference double o-ring fit there is also gravity. So when you shut your engine off your dip stick just starts to levitate out of the tube?
If your blowing your dip stick out of an OEM production vehicle you have a defective stick, tube or too much crankcase pressure building up. And even on a high boost engine you have an issue as you are not properly evacuating the crankcase for the build. Then there are those that put a blower on their 2.4's and 2.2's that blocked off the PCV system wondering what went wrong.
I love when people say they've been gm techs or engineers for some odd years. Who cares? Ive been wiping my ass for 20 years, and sometimes I still get **** everywhere.
I love when people say they've been gm techs or engineers for some odd years. Who cares? Ive been wiping my ass for 20 years, and sometimes I still get **** everywhere.
i have to say this may be one of the funniest things ive ever seen
Ok... for those that give a **** while some are still learning how to wipe their ass.
An example of the absolute air pressure / vacuum correlation within the intake manifold of a boosted car at sea level capable of creating 15psi of boost
That is my point but that is not what he is saying. I believe there are a lot of members here that don't quite understand vacuum, atmospheric pressure and boost, little lone what goes on in the crank case. At WOT all naturally aspirated engines drop to zero or near zero engine vacuum. Around 7" H2O or less. Their dip sticks do no come out.
na engines drop to 0in but the vacuum source to keep a negative pressure on the engine changes locations to before the throttle plate at wot and without that the dip stick will pop right out
na engines drop to 0in but the vacuum source to keep a negative pressure on the engine changes locations to before the throttle plate at wot and without that the dip stick will pop right out
Sadly you do not understand even the most basic principles of an internal combustion engine.
That doesn't surprise me as most who grew up after the carbureted cars were out of production don't. It's the fact that you're still trying to explain that engine vacuum at WOT moves to different places within the engine
09-13-2017, 04:52 PM
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