Supercharge the S4 for $1500???
02-06-2003, 03:58 AM
#61
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The MAF heats the hot wire a fixed amount above the temperature of the air passing through it. That means if it was in front of the supercharger the difference in temperature between the sensor wire and the air is the same as the difference in temperature between the sensor wire and the air if it was behind the supercharger. That takes care of the differences in air temperature as being a factor in how well it can cool the sensor wire. If it wasn't for that fixed temperature difference above the air passing through it, cold air would cool the wire more efficiently than hot air even if their mass was the same.
If the MAF is placed in front of the supercharger, the air velocity is greater, and the density is less (the air molecules are further apart). The air is moving fast, which would cool the wire well. Those air molecules are spaced relatively far apart though, so not as many of them are actually striking the hot sensor wire to remove heat from it, which wouldn't cool the sensor wire well.
If the MAF is placed behind the supercharger, the air velocity is lower, and the density greater (the air molecules are packed closer together). The air is moving slow, which would cool the wire poorly. Those air molecules are packed close together though, so a lot more of them are striking the hot sensor wire to remove heat from it.
The actual mass of the air (number of molecules) going through the MAF is the same either way. In the first example you've got fewer fast moving molecules hitting and taking heat from the sensor wire. In the second example you've got slower moving molecules taking heat from the sensor wire, but you've got a lot more of them hitting the wire and doing that heat removal.
Think of the air molecules moving through the MAF as cars moving through a toll booth. Since the temperature of the sensor wire is a fixed amount above any air that passes through it, it would be like every car paying the same toll (amount of heat removed from the sensor wire), and no more or less as they passed through. Putting the MAF (toll booth) in front of the supercharger would be like widely spaced cars, driving through fast, and each paying a $1 toll (removing heat from sensor wire). Putting the MAF (toll booth) behind the supercharger would be like a traffic jam of cars, driving slowly, and each paying a $1 toll (removing heat from the sensor wire). Either way you'd be getting the the same amount of dollars (heat removed from the sensor wire) in the toll booth (MAF), and the same number of cars would be counted as having passed through. The number of cars that passed through would be representative of the number or mass of air molecules, and the dollar count would be representative of the MAF signal to the computer. Hopefully the computer will put that signal to better use than the tollway authority does those dollars.
If the MAF is placed in front of the supercharger, the air velocity is greater, and the density is less (the air molecules are further apart). The air is moving fast, which would cool the wire well. Those air molecules are spaced relatively far apart though, so not as many of them are actually striking the hot sensor wire to remove heat from it, which wouldn't cool the sensor wire well.
If the MAF is placed behind the supercharger, the air velocity is lower, and the density greater (the air molecules are packed closer together). The air is moving slow, which would cool the wire poorly. Those air molecules are packed close together though, so a lot more of them are striking the hot sensor wire to remove heat from it.
The actual mass of the air (number of molecules) going through the MAF is the same either way. In the first example you've got fewer fast moving molecules hitting and taking heat from the sensor wire. In the second example you've got slower moving molecules taking heat from the sensor wire, but you've got a lot more of them hitting the wire and doing that heat removal.
Think of the air molecules moving through the MAF as cars moving through a toll booth. Since the temperature of the sensor wire is a fixed amount above any air that passes through it, it would be like every car paying the same toll (amount of heat removed from the sensor wire), and no more or less as they passed through. Putting the MAF (toll booth) in front of the supercharger would be like widely spaced cars, driving through fast, and each paying a $1 toll (removing heat from sensor wire). Putting the MAF (toll booth) behind the supercharger would be like a traffic jam of cars, driving slowly, and each paying a $1 toll (removing heat from the sensor wire). Either way you'd be getting the the same amount of dollars (heat removed from the sensor wire) in the toll booth (MAF), and the same number of cars would be counted as having passed through. The number of cars that passed through would be representative of the number or mass of air molecules, and the dollar count would be representative of the MAF signal to the computer. Hopefully the computer will put that signal to better use than the tollway authority does those dollars.
