air flow meter location...
- Thread starter mitto
- Start date
hmmm, the only issue I can see is that it would then be measuring the air post turbo, so it would potentially see a much greater range of air temperatures than normal.
Assuming that isn't a problem I don't see why you can't do it
Where's the air filter located in that setup?
Assuming that isn't a problem I don't see why you can't do it
Where's the air filter located in that setup?
from the looks of it in the front wing? i only have the one pic. just wondering cus it would mean i could make a venturi style intake system if i can move the AFM to that side. could you see a problem with the air being pressurized or breaking the sensor? surely the air moves slowerat that point? cus obviously the turbo has to suck air in VERY fast to fill the i/c - inlet system?
JonGTSt
Member
Mat,
Correct me if im talking crap but I thought hot wire AFM's measured air flow at normal atmospheric pressure, on the boosted side of the turbo it wouldn't get the same readings because of constantly changing pressure. I imagine it would be easier to go fcon-pro or pfc-pro and convert to MAP sensor..
my 2ps
Correct me if im talking crap but I thought hot wire AFM's measured air flow at normal atmospheric pressure, on the boosted side of the turbo it wouldn't get the same readings because of constantly changing pressure. I imagine it would be easier to go fcon-pro or pfc-pro and convert to MAP sensor..
my 2ps
Captain Muppet
Pro-tard
Compressed air will cool the wire more than atmosheric, but will flow slower for a given mass flow - so the measurement is independant of pressure. It'll see the same mass flow of air in either location, it's just on the high pressure side the air will be moving slower and will be warmer.
As long as the temperature compensating thermocouple has enough range it should work fine, although with a nice big intercooler the temperature shouldn't get all that hot anyway.
As long as the temperature compensating thermocouple has enough range it should work fine, although with a nice big intercooler the temperature shouldn't get all that hot anyway.
JonGTSt
Member
Maybe its not running an AFM and the housing is just used as a bodge to make up the gap? maybe not.. 
I cant see an AFM running like that, possibly its been modded to house a map sensor, but that should be tapped in to the inlet plenum
Find out about that car dude, i want to know now
I cant see an AFM running like that, possibly its been modded to house a map sensor, but that should be tapped in to the inlet plenum
Find out about that car dude, i want to know now
JonGTSt
Member
The guys on SDU seem to know of this being used..
http://forums.skylinesdownunder.co.nz/showthread.php?s=&threadid=37564&highlight=afm+after
Im still unsure that the AFM would measure the same flow rate that it would get at 1 atmosphere, why would nissan and other manufacturers put them in front of the turbo to start with...
Questions
1) Will the mass of the air passing the hot wire be different dependant on what the boost is doing?
2) Will the intake temperature adversly effect the cooling of the hot wire to the point that it will not produce consistant readings, and is the OEM postion designed to give more consistant readings from ambient air temperature?
3) Does the increased pressure also increase the resistance/cooling of the hot wire proportionately so that it doesnt really matter?
Im sure the answers are out there m8 but I aint a rocket scientist, maybe just try it and see.. it could work fine, it certainly seems to have done for other people
Jon
http://forums.skylinesdownunder.co.nz/showthread.php?s=&threadid=37564&highlight=afm+after
Im still unsure that the AFM would measure the same flow rate that it would get at 1 atmosphere, why would nissan and other manufacturers put them in front of the turbo to start with...
Questions
1) Will the mass of the air passing the hot wire be different dependant on what the boost is doing?
2) Will the intake temperature adversly effect the cooling of the hot wire to the point that it will not produce consistant readings, and is the OEM postion designed to give more consistant readings from ambient air temperature?
3) Does the increased pressure also increase the resistance/cooling of the hot wire proportionately so that it doesnt really matter?
Im sure the answers are out there m8 but I aint a rocket scientist, maybe just try it and see.. it could work fine, it certainly seems to have done for other people
Jon
Captain Muppet
Pro-tard
I'm guessing that the manufactures put the AFM just behind the filter to get commonality of parts and assemblies with NA cars, plus positioned before the turbo and breather pipe connections the air is clean, so the AFM won't get covered in oily shite.
Answers (I'm not a rocket scientist but I am a powertrain design engineer)
1) Mass flow is independant of pressure - you change the pressure for a given mass flow and the velocity of the air will change to compensate.
2) Within the range of the temperature compensating thermocouple on the AFM it will provide consistant readings. I'd be surprised if the air between the intercooler and inlet manifold got too hot for it.
3) Yes, the increased pressure increases the cooling of the hot wire proportionately so that it doesnt really matter
So it'll work, but it'll get dirty and may fall over if inlet temperatures get very high post intercooler.
Answers (I'm not a rocket scientist but I am a powertrain design engineer)
1) Mass flow is independant of pressure - you change the pressure for a given mass flow and the velocity of the air will change to compensate.
2) Within the range of the temperature compensating thermocouple on the AFM it will provide consistant readings. I'd be surprised if the air between the intercooler and inlet manifold got too hot for it.
3) Yes, the increased pressure increases the cooling of the hot wire proportionately so that it doesnt really matter
So it'll work, but it'll get dirty and may fall over if inlet temperatures get very high post intercooler.