Maf Under Pressure Boost
03-10-2006, 10:48 AM
#1
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arg, is there a way to edit titles, that should be maf under pressure of boost...
anyways does anyone know how bad it is to run a the maf under boost? by this I mean after the turbo.
really I'm trying to come up with a way to not have to recirculate my bov until i get a piggy back of some type. I'm only planning on running 5 psi right now and am going to be using my old cai temporarily anyways.
anyways does anyone know how bad it is to run a the maf under boost? by this I mean after the turbo.
really I'm trying to come up with a way to not have to recirculate my bov until i get a piggy back of some type. I'm only planning on running 5 psi right now and am going to be using my old cai temporarily anyways.
03-10-2006, 12:48 PM
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im not really sure about the recirc. issue and all of that, but this is my opinion..
some people run it b4, some people run it after. i have seen arguements both ways, but the way i think of it, is the MAF on the N/A application recieves air that is essentially ambient and being 'sucked' in.
with a turbo application, its basically the same as tha N/A application putting the MAF before the turbo, just getting ALOT more air sucked in..
with putting the MAF after the turbo, there will be pressurized air, and much warmer air passing thru the sensitive element. i would think that it would decrease the life of the MAF dramatically, but i am just looking at this from a physical, logical point of view, i dont really know the technical reasons to do it either way, hopefully someone with more experience/knowledge will chime in.. hopefully i helped a lil..
i have mine b4 the turbo by the way, and i know if you do it b4 turbo, have it as far away as possible..
some people run it b4, some people run it after. i have seen arguements both ways, but the way i think of it, is the MAF on the N/A application recieves air that is essentially ambient and being 'sucked' in.
with a turbo application, its basically the same as tha N/A application putting the MAF before the turbo, just getting ALOT more air sucked in..
with putting the MAF after the turbo, there will be pressurized air, and much warmer air passing thru the sensitive element. i would think that it would decrease the life of the MAF dramatically, but i am just looking at this from a physical, logical point of view, i dont really know the technical reasons to do it either way, hopefully someone with more experience/knowledge will chime in.. hopefully i helped a lil..
i have mine b4 the turbo by the way, and i know if you do it b4 turbo, have it as far away as possible..
03-10-2006, 01:17 PM
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I wouldn't run the MAF after the turbo - the positive boost pressure will distort readings. You can run the BOV to atomsphere, you'll just run super rich during shifts.
Messing up MAF readings can make you run lean, venting the BOV to the atmosphere can only make you run rich. I'd pick the latter.
It seems like you are rushing things a bit anyhow. I'd wait until you have the cash and time to get it all put together correctly the first time, rather than ghetto-rigging it so you can run boost ASAP.
Messing up MAF readings can make you run lean, venting the BOV to the atmosphere can only make you run rich. I'd pick the latter.
It seems like you are rushing things a bit anyhow. I'd wait until you have the cash and time to get it all put together correctly the first time, rather than ghetto-rigging it so you can run boost ASAP.
03-10-2006, 01:22 PM
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Trust me, do shit right the first time. You might even want to wait and get a serious engine management system like a standalone.
03-10-2006, 02:08 PM
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yah, what a_gut said seems to pretty much sum it all up.. if your gonna only push 5psi and not push your car hard, id put the MAF before the turbo and vent to the atmosphere. at those Psis, with minor management system, you shouldnt run toooo rich.. i know when i didnt have my MAF clamp set right and i would boost hi, and shift, and not give her any gas, she would run rich as HELL and die..
i wouldnt rush it like jon said, and save for it all at once, but you dont need anything close to a standalone if your just going to be using a mild to moderate setup..
i wouldnt rush it like jon said, and save for it all at once, but you dont need anything close to a standalone if your just going to be using a mild to moderate setup..
03-10-2006, 02:47 PM
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QUOTE (a_gut @ Mar 10 2006, 10:33 PM)
That puts the MAF under positive boost pressure.
it would be same amount of air going through the MAF, but air will not be that hot
03-10-2006, 03:57 PM
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but our mafs cannot sense pressure. I agree with what 01importshark said. putting it before the turbo is essentially sucking all the moving air through the maf, while after turbo the air isnt as much moving as there being continuous pressure... i dont know if that makes sense, but it just doenst even seem like it would work well.
03-10-2006, 05:37 PM
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You can go with a normal BOV and put the MAF before the Compressor IF you adhere to the following guidelines.
The BOV must be closed 100% of the time, UNLESS
A. There is positive pressure in the charge piping
B. The Throttle body is closed,nearly closed.
The MAF must be at least 12" away from the Compressor/exhaust manifold. It must seperated via silocone connectors from any metal piping.
If you hook up your BOV the way most people do, it opens under vaccum and you suck in un metered air 90% of the time. The BOV only "closes" when it senses positive pressure. THIS IS WRONG. THIS IS RICE. This vents ANY positive pressure everytime there is intake manifold vacuum, and makes the fun "psssht" sound when you shift/let off the throtttle. This is the RICE way to hook up a BOV. It makes a lot of noise, and it's what 99% of people do. But it's not the RIGHT way to install/use a BOV.
The BOV must Vent ONLY POSITIVE PRESSURE, not stay open anytime there is intake manifold vacuum.
The ONLY purpose of a BOV is to vent the pressure wave that MAY form when you close the throttle butterfly. As such, your BOV should be set to open 1-2 PSI HIGHER than your wastegate. SO if your wastegate is set to 5psi, your BOV shouldn't open unless 6-7 PSI is regisgered in the Charge pipe betwen the TB and Compressor, and ONLY stay open long enought to vent that exess pressure. If the charge piping never registers that high of a boost spike. Guess what? It didn't need to open, and it shouldn't.
The BOV must be closed 100% of the time, UNLESS
A. There is positive pressure in the charge piping
B. The Throttle body is closed,nearly closed.
The MAF must be at least 12" away from the Compressor/exhaust manifold. It must seperated via silocone connectors from any metal piping.
If you hook up your BOV the way most people do, it opens under vaccum and you suck in un metered air 90% of the time. The BOV only "closes" when it senses positive pressure. THIS IS WRONG. THIS IS RICE. This vents ANY positive pressure everytime there is intake manifold vacuum, and makes the fun "psssht" sound when you shift/let off the throtttle. This is the RICE way to hook up a BOV. It makes a lot of noise, and it's what 99% of people do. But it's not the RIGHT way to install/use a BOV.
The BOV must Vent ONLY POSITIVE PRESSURE, not stay open anytime there is intake manifold vacuum.
The ONLY purpose of a BOV is to vent the pressure wave that MAY form when you close the throttle butterfly. As such, your BOV should be set to open 1-2 PSI HIGHER than your wastegate. SO if your wastegate is set to 5psi, your BOV shouldn't open unless 6-7 PSI is regisgered in the Charge pipe betwen the TB and Compressor, and ONLY stay open long enought to vent that exess pressure. If the charge piping never registers that high of a boost spike. Guess what? It didn't need to open, and it shouldn't.