I want to modify my PCV setup...
10-22-2006, 04:49 PM
#1
I want to modify my PCV setup...
...so that I can have an undiluted mixture.
I have a breather on my front valve cover, can I add one to the rear?
Instead of running a catch can, can I just run a line to dump the oil that would be recirculated?
Thanks in advance for any advice!
I have a breather on my front valve cover, can I add one to the rear?
Instead of running a catch can, can I just run a line to dump the oil that would be recirculated?
Thanks in advance for any advice!
10-22-2006, 05:01 PM
#2
Found this post:
Originally Posted by got rice?
you'll need to richen the mixture from 1000 rpm to about 3000 rpm, which is the rpm range that the EGR is functional.
everyone thinks that recirculating burnt exhaust gas back into the combustion chamber is such a terrible thing - it's not. The burnt exhaust gas is inert, so by taking up space within the combustion chamber, it prevents a full usage of the space within. This space <I>could've</I> been filled with fresh intake charge. Since the gas is inert and fills up the space within, it keeps the combustion chamber's temperature lower. Lower temperatures result in two things: 1) lower oxides of nitrogen 2) less chances of detonation.
Detonation occurs when the cylinder pressures and temperatures are high. Since the EGR recirculates the burnt exhaust gas through and keeps the temps down, it lowers the detonation threshold. So why is it important to richen the a/f mixture? When the EGR is removed, the cylinder temps increase, increasing the detonation possibilities for two reasons: 1) detonation is most likely to occur where large amounts of torque is made in XXX rpm range 2) detonation occurs when the temps are high (as stated above). The Maxima engine makes a lot of torque in the 2000-3000 rpm range, so by removing the EGR system you're shooting yourself in the foot.
in summary, it's not worth it. the EGR is not active at wide open throttle or above 3000ish rpm. You will not find a performance gain by doing so.
everyone thinks that recirculating burnt exhaust gas back into the combustion chamber is such a terrible thing - it's not. The burnt exhaust gas is inert, so by taking up space within the combustion chamber, it prevents a full usage of the space within. This space <I>could've</I> been filled with fresh intake charge. Since the gas is inert and fills up the space within, it keeps the combustion chamber's temperature lower. Lower temperatures result in two things: 1) lower oxides of nitrogen 2) less chances of detonation.
Detonation occurs when the cylinder pressures and temperatures are high. Since the EGR recirculates the burnt exhaust gas through and keeps the temps down, it lowers the detonation threshold. So why is it important to richen the a/f mixture? When the EGR is removed, the cylinder temps increase, increasing the detonation possibilities for two reasons: 1) detonation is most likely to occur where large amounts of torque is made in XXX rpm range 2) detonation occurs when the temps are high (as stated above). The Maxima engine makes a lot of torque in the 2000-3000 rpm range, so by removing the EGR system you're shooting yourself in the foot.
in summary, it's not worth it. the EGR is not active at wide open throttle or above 3000ish rpm. You will not find a performance gain by doing so.
10-23-2006, 06:22 AM
#3
Originally Posted by Fr33way™
I have a breather on my front valve cover, can I add one to the rear?
Instead of running a catch can, can I just run a line to dump the oil that would be recirculated?
Instead of running a catch can, can I just run a line to dump the oil that would be recirculated?
10-23-2006, 04:44 PM
#4
I have been doing a good amount of reading on the subject and it seems like what I was thinking of was a venturi setup on a muscle car.
The crankcase needs a vacuum source to pull the blowby gases from the front valvecover to the rear, and then through the PCV valve during a vacuum situation (idle, light acceleration).
The breather on the front valve cover prevents this mix (blowby oil vapors) from going back into the intake (via the stock resonator) in a low to zero vacuum situation such as full throttle acceleration.
I had my terms mixed up. I think that I may implement a sort of catch-can setup in the future. I apologize for the painfully n00bish thread in this section.
The crankcase needs a vacuum source to pull the blowby gases from the front valvecover to the rear, and then through the PCV valve during a vacuum situation (idle, light acceleration).
The breather on the front valve cover prevents this mix (blowby oil vapors) from going back into the intake (via the stock resonator) in a low to zero vacuum situation such as full throttle acceleration.
I had my terms mixed up. I think that I may implement a sort of catch-can setup in the future. I apologize for the painfully n00bish thread in this section.
10-23-2006, 06:07 PM
#6
I have a catch can for the rear VC, and a 
breather for the front VC. So essentially no vapors going back to the IM.
Seems to work just fine, funny idle, but it's not anything I can't live with.
BTW, this is an A33B.
breather for the front VC. So essentially no vapors going back to the IM.Seems to work just fine, funny idle, but it's not anything I can't live with.
BTW, this is an A33B.
10-23-2006, 06:52 PM
#8
Supporting Maxima.org Member
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Originally Posted by krismax
i just did what jime did breather on both ,no more mess more simple
Any more imput on just running two breathers
-matt
10-23-2006, 07:34 PM
#9
Originally Posted by JSutter
So clarify what you want to do exactly.
I wanted to elimiate the blowby vapors from the mixture. The more I read however I hear the opinion that these gases reduce combustion temperatures and can also be benificial.
10-23-2006, 08:51 PM
#10
Originally Posted by Fr33way™
The more I read however I hear the opinion that these gases reduce combustion temperatures and can also be benificial.
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