my FI PCV/Crank VAC system.
Thread Starter
Joined: Nov 2001
Posts: 10,018
Likes: 51
From: Virginia
boostaholic
under boost the vaccum does not come from intake vaccum, but from the vaccum created when the turbo is sucking air through the air filter. going to this pipe i have two 3/8" hoses. if this amount of draw on the crankcase still is not enough, and there begins to be pressure, i another valve on the valvecover that is exit only where any positive pressure can escape.
under vaccum the above hoses are the air leak that limits the vaccum in the crankcase to at or under 5" and the one way valve on the valvecover is sucked shut.
kaos, that would work, but be careful that the one hose to the turbo pipe may not be enough to allow positive pressure to be drawn out, maybe explore some of the brake booster valves like the one on my valvecover.
the only thing i dont like is that the intake can suck some fresh air straight from the air filter hose, where i am pulling out the 'dirty' air from across the opposite side of the engine.
under boost the vaccum does not come from intake vaccum, but from the vaccum created when the turbo is sucking air through the air filter. going to this pipe i have two 3/8" hoses. if this amount of draw on the crankcase still is not enough, and there begins to be pressure, i another valve on the valvecover that is exit only where any positive pressure can escape.
under vaccum the above hoses are the air leak that limits the vaccum in the crankcase to at or under 5" and the one way valve on the valvecover is sucked shut.
kaos, that would work, but be careful that the one hose to the turbo pipe may not be enough to allow positive pressure to be drawn out, maybe explore some of the brake booster valves like the one on my valvecover.
the only thing i dont like is that the intake can suck some fresh air straight from the air filter hose, where i am pulling out the 'dirty' air from across the opposite side of the engine.
Have you tried this w/o the vacuum reliefs? And, if so whats the highest you saw? Just wondering since I had always been told that 12-14inches was optimal and we could never pull that much.
Thread Starter
Joined: Nov 2001
Posts: 10,018
Likes: 51
From: Virginia
at 11" i heard a squealing, talking to kurt he told me that it was air sucking past the front / rear crankshaft seal. said it didnt hurt anything but was annoying to hear on a street car.
i would like to run more, but without a really large one way valve to vent any pressure, you can only get so much vaccum while still allowing plenty of pressure relief.
for instance when i had it at 11" at idle, it was because i only had 1 hose going to the filter from the crankcase, and no valve on top of the valve cover. when i punched it with that i let off at 2psi cankcase pressure which was unacceptable
i would like to run more, but without a really large one way valve to vent any pressure, you can only get so much vaccum while still allowing plenty of pressure relief.
for instance when i had it at 11" at idle, it was because i only had 1 hose going to the filter from the crankcase, and no valve on top of the valve cover. when i punched it with that i let off at 2psi cankcase pressure which was unacceptable
i would hate to see what my crank case pressure is if you are letting off at 2 psi mine was horrible. MM what if i ran two hoses to the can would that make a difference. really what i need is for you to tell me exactly how to do this, rememger im a retard that knows nothing. think of me as a elementry school kid.
This is a great thread. Has anyone here hear of this thing:
http://www.et-performance.com/tech_info.html
Sounds good. Seems popular with 3000GT VR-4s and supercharged Vipers.
http://www.et-performance.com/tech_info.html
Sounds good. Seems popular with 3000GT VR-4s and supercharged Vipers.
Last edited by bone324; Jun 4, 2006 at 03:40 AM.
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Brett Foote how are you drawing vaccum from the break booster? at WOT the turbo is blowing air to the back of the intake and to the break booster right so how exactly is this sucking air out of the engine? or am i missing something. like i said im an idiot
Teching In
Joined: Sep 2005
Posts: 26
Likes: 0
From: Bloomingdale Il
This is the Vaccum pump/oil seperator setup I made for my C6 Vette with Ls2 402 D1SC@15psi. It sits in my factory battery tray (battery relocated to rear compartment like Z06).
When idling, lite cruising and no boost conditions the pump will be off and will act as vented a catch can setup.I am using a boost switch to activate the pump. I will start the pump with 3psi of boost to start off.
It pulls -5 vaccum with a high cfm so should it hold it at high RPM. I did bench testing that looks promising. I am putting the motor in the car this week.I'll keep you updated with the results with a post when it's installed if anybody is interested.
When idling, lite cruising and no boost conditions the pump will be off and will act as vented a catch can setup.I am using a boost switch to activate the pump. I will start the pump with 3psi of boost to start off.
It pulls -5 vaccum with a high cfm so should it hold it at high RPM. I did bench testing that looks promising. I am putting the motor in the car this week.I'll keep you updated with the results with a post when it's installed if anybody is interested.
Thread Starter
Joined: Nov 2001
Posts: 10,018
Likes: 51
From: Virginia
c6 dude, nicely executed. i ran my stock air pump as a scavenge pump under WOT for a summer until it got killed with oil. yours should last longer with the catch can in front of it.
kaos the brake boost valve seals under boost. no vaccum happens from there.
however under boost there is a draw from the other side of the engine, where the two hoses go to the air filter pipe before the turbo. at high flow there is a pressure lower than atmospheric between the air filter and turbo (or supercharger). this mostly just helps to move air through the engine i guess, as i dont read any actual vaccum at wide open.
kaos the brake boost valve seals under boost. no vaccum happens from there.
however under boost there is a draw from the other side of the engine, where the two hoses go to the air filter pipe before the turbo. at high flow there is a pressure lower than atmospheric between the air filter and turbo (or supercharger). this mostly just helps to move air through the engine i guess, as i dont read any actual vaccum at wide open.
Thread Starter
Joined: Nov 2001
Posts: 10,018
Likes: 51
From: Virginia
the hose from the brake booster is connected as stock. the change was i cut it and put a t into it that goes to a catchcan, then a 1 way valve, then to the valvecover
the hoses from the turbo pipe to the engine are on the front passenger corner. please review the photos
the hoses from the turbo pipe to the engine are on the front passenger corner. please review the photos
Thread Starter
Joined: Nov 2001
Posts: 10,018
Likes: 51
From: Virginia
there are two important routes for my set up.
route 1.
intake to oil separator to 1way check valve to engine
route 2.
pre-turbo fitting to engine
vary the size and number of route 2's to reach appropriate vaccum and pressure release by hooking boost gauge to engine
the configuration doesn't matter but i would try to put the routes on different ends and sides of the engine so you have as much fresh air turnover through the engine as possible.
route 1.
intake to oil separator to 1way check valve to engine
route 2.
pre-turbo fitting to engine
vary the size and number of route 2's to reach appropriate vaccum and pressure release by hooking boost gauge to engine
the configuration doesn't matter but i would try to put the routes on different ends and sides of the engine so you have as much fresh air turnover through the engine as possible.
Thread Starter
Joined: Nov 2001
Posts: 10,018
Likes: 51
From: Virginia
just make sure you have plenty of are for the engine to vent (or have gasses sucked) out of during boost. don't seal up the crankcase and DON'T blow boost into it.
Originally Posted by MiaSSmaro98
damn i still dont get this whole pcv crap for boost
Are you serious? I even drew 2 pics in the other thread. I seriously dont think you need to be in FI or have a shop do it all for you.
way to be supportive. for those of us that are FI illiterate it takes a while for us to get it. mia dont worry about county boy. i finally got mine figured out. it doesnt blow anymore oil. a check valve between the intake to a catch can then from the can to the vally cover. then a line in front of the turbo. no issues yet. plus venting the valve covers. seems to work great so far