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.

LS1derfull

7.5 g/sec @850 346" MMS 220*on a 112* 100*F

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

horist

looks like it bounces around 9.20

382, 236/242 593/603 112 cam, 120s IAT

LS1derfull

My bad i stated my idle gms/sec were 7.5 but i checked today and they were around 8.5 at same idle rpm.

Bink

Altitude doesn't effect mass - that's a major advantage of using the MAF.
Common misconception.

joel

NicD

iTrader: (7)

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.

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

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

Bink

Nope...that IS my point. I completely agree with you.

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

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

red ws6 99

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

P Mack

iTrader: (6)

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.

NicD

iTrader: (7)

Now that makes sense. The density of air will be different at elevation compared to sea level and the motor obviously doesn't change displacement so the mass air meter will read that difference.

Another_User

The dynamic air on my MAFless setup says that it is getting about 10 g/sec at idle @900rpms.

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)

Another_User

Your PCM dynamic air will read the same as your MAF. I am MAFless. Pull the plug on your MAF and watch that number change when you restart your car.

P Mack

iTrader: (6)

Found and old log file from when I was stock.

Same as my other post except no headers or cam.

Altitude: 7000 ft
Baro: 80 kpa
MAF: 4.9 g/s
MAP: 24 kpa