Survey: How much airflow at idle.
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From: new england
Originally Posted by QuickSilver2002
Just trying to collect some data from different cars.
How many g/sec of air do you move at idle.
Please specify. RPM, CI, CAM, and IAT.
How many g/sec of air do you move at idle.
Please specify. RPM, CI, CAM, and IAT.
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Originally Posted by red ws6 99
You should also be asking at what altitude (makes a huge difference) you are at and other relevent mods like turbos.
Gary
Gary
Common misconception.
joel
Originally Posted by Bink
Altitude doesn't effect mass - that's a major advantage of using the MAF.
Common misconception.
Common misconception.
I would think that the mass of the air does change with altitude. The main benefit of the MAF is that it can read that change.
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Originally Posted by Nic00Z28M6
I would think that the mass of the air does change with altitude. The main benefit of the MAF is that it can read that change.
Altitude effects density. Density = mass/volume. The higher the altitude the less mass per unit area. MAF outputs (theoretically) frequency = mass/sec.
So altitude does not change it - you'll need to flow a greater volume of air at higher altitude to get the same air mass into the engine. Make sense??
joel LS1 Tech Stories
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From: Las Cruces, NM
Originally Posted by Bink
Altitude effects density. Density = mass/volume. The higher the altitude the less mass per unit area. MAF outputs (theoretically) frequency = mass/sec.
So altitude does not change it - you'll need to flow a greater volume of air at higher altitude to get the same air mass into the engine. Make sense??
joel
So altitude does not change it - you'll need to flow a greater volume of air at higher altitude to get the same air mass into the engine. Make sense??
joelGary
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Originally Posted by red ws6 99
Think you missed the point. With less oxygen in the air you will have less mass flow into the engine for any given rpm when compared to sea level. I am only moving 4.5 g/s at 550 rpm, at sea level car would be moving ~6.5 g/s (what the air flow tables are programmed for). It makes the car sound like they have an nice cam in them at higher altitude, since they are barely running.
Gary
Gary
The beauty of the MAF is it is able to accurately report the mass of air and thus the PCM can accurately deliver the correct amount of fuel. The correct mass of air is reported regardless of density. MAFLESS ( Speed Density) - atmospheric pressures( Baro) has a huge effect on the tune due to fueling inaccuracies. Think about the density changes with elevation!! Nightmare.
I'm not trying to argue........just trying to stop the myth.
joel Last edited by Bink; Sep 15, 2004 at 07:50 PM.
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From: Las Cruces, NM
Originally Posted by marc_w
You're talking metered, not "requested via the table", right?
7-8 in P/N.
7-7.5 in G.
Requested:
6.25 in P/N
6.50 in G
7-8 in P/N.
7-7.5 in G.
Requested:
6.25 in P/N
6.50 in G
I am talking what the maf is reporting without the air conditioner on. With air conditioner on the numbers jump up a bunch ~1.5 g/s
Gary
I have logs from San Antonio (800 ft, 100 kpa baro) and Colorado Springs (7000 ft, 80 kpa baro). Both are with a 222/222 112 lsa cam, 800 rpm idle, 5.7 liter.
San Antonio: 7.8 g/s
C Springs: 6.7 g/s
Oh yeah, and MAP at idle was ~50 kpa in San Antonio, ~40 kpa in the Springs.
San Antonio: 7.8 g/s
C Springs: 6.7 g/s
Oh yeah, and MAP at idle was ~50 kpa in San Antonio, ~40 kpa in the Springs.
Originally Posted by P Mack
I have logs from San Antonio (800 ft, 100 kpa baro) and Colorado Springs (7000 ft, 80 kpa baro). Both are with a 222/222 112 lsa cam, 800 rpm idle, 5.7 liter.
San Antonio: 7.8 g/s
C Springs: 6.7 g/s
Oh yeah, and MAP at idle was ~50 kpa in San Antonio, ~40 kpa in the Springs.
San Antonio: 7.8 g/s
C Springs: 6.7 g/s
Oh yeah, and MAP at idle was ~50 kpa in San Antonio, ~40 kpa in the Springs.
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Originally Posted by deezel
570 RPM, 364c.i. (6.0L), stock cam, IAT 91*F
MAF and PCM dynair both agree:
P/N = 7.3 g/s (MAP 38)
In gear = 7.8 g/s (MAP 42)
MAF and PCM dynair both agree:
P/N = 7.3 g/s (MAP 38)
In gear = 7.8 g/s (MAP 42)
