MAT Sensor Location on FMIC

[rcparks1]

To you experienced BTR guys, this may seem like a stupid question. I have an 87 TR, Te44, 009 inj., Prog. Alky, Cotton FMIC. Question is: When you have an intercooler, especially front mount..wouldn't it make more sense and be more accurate to have the mat sensor on the pipe between the FMIC and the throttle body, obviously not between the alky and tb. This would be the actual temp of the air entering the motor. Currently mine is mounted on the K+N flange.
Don't mean to be ignorant. Thanks

 

[scottyb]

My understanding of the MAT sensor is that it has little to do with actual temp of the "intake charge". It is used in conjunction with the MAF to correct for deviations in the MAF readings based on temperature changes. In other words, the MAF reads slightly different if the air is cold vs being warm. The MAT allows for temp compensation.

If this is true, then placement of the MAT where you suggest would skew the MAF reading incorrectly.

Of course i could be wrong. Do a search for MAT.

 

[rcparks1]

Thanks, I guess I didn't understand the actual function of the MAT. So its just used to kind of double check the temp the maf reads. Thanks again, Ray

 

[scottyb]

Thanks, I guess I didn't understand the actual function of the MAT. So its just used to kind of double check the temp the maf reads. Thanks again, Ray

The MAF reads airflow, which is a significant player. Because of it's design, changes in temperture can alter it's airflow reading. I believe the MAT temp reading is used to correct the airflow readings at extreme temperatures.

 

[bruce]

To you experienced BTR guys, this may seem like a stupid question. I have an 87 TR, Te44, 009 inj., Prog. Alky, Cotton FMIC. Question is: When you have an intercooler, especially front mount..wouldn't it make more sense and be more accurate to have the mat sensor on the pipe between the FMIC and the throttle body, obviously not between the alky and tb. This would be the actual temp of the air entering the motor. Currently mine is mounted on the K+N flange.
Don't mean to be ignorant. Thanks

http://www.t6p.com/forums/showthread.php?t=7607
http://www.t6p.com/forums/showthread.php?t=7557

It actually makes more sense to place it in the plenum area (upper doghouse), and then redo the timing tables so they work. When in doubt the library is you friend <G>

 

[scottyb]

http://www.t6p.com/forums/showthread.php?t=7607
http://www.t6p.com/forums/showthread.php?t=7557

It actually makes more sense to place it in the plenum area (upper doghouse), and then redo the timing tables so they work. When in doubt the library is you friend <G>

Now I'm confused. Your link stated that the MAT is for MAF temp sompensation. So Am I wrong in assuming that the 2 kinda go hand-in-hand?

 

[bruce]

Now I'm confused. Your link stated that the MAT is for MAF temp sompensation. So Am I wrong in assuming that the 2 kinda go hand-in-hand?

The Manifold Air Temp. is used as a correction for the Mass Air Flow sensor.

In oem form, the GN *MAT*, is actually, an Intake Air Temp sensor. Since it just reads the temp., of the air in the intake tract. A Manifold Air Temp sensor measures the air temp of the air in the intake manifold.

The GN MAF, is a rather primitive design, and needs the IAT/MAT to correct it's readings.

To give the ecm the best and most accurate data to work with, means measuring what's going into the engine as it goes past the intake valve (or as close as posible). Well, actually an in chamber sensor would be best, but that's still a long way off, from what I hear. Any way, the better the info is the ecm has, the better it can account for what will make the engine happiest.

 

[scottyb]

The GN MAF, is a rather primitive design, and needs the IAT/MAT to correct it's readings.

If the IAT is used for MAF correction, then wouldn't it be best to place the MAT right next to the MAF?

If the MAT sensor is "after turbo", then wouldn't the hotter temp reading yield an incorrect MAF sensor airflow correction?

 

[rcparks1]

Ok Guys, Which is it? Should it be after turbo at plenum for actual temp.(in an ideal world) . Or is it a check factor for the maf? The compressed charge should be cooler because of the IC? or how about after alcohol? I think that would be much cooler than initial intake temp???

 

[bruce]

Or is it a check factor for the maf? The compressed charge should be cooler because of the IC? or how about after alcohol? I think that would be much cooler than initial intake temp???

It's not a check factor, is supplies information that allows the MAF's calibration to be corrected.

The compressed air leaving the turbo is hotter then ambient. Compressing air, heats it up.
If the alky is in fact cooling the incoming air to below ambient, wouldn't it make sense to compensate for that?.

But, if you're not getting a chip that accounts for the new location, then it's not really to important what you do... That was the reason for the references to the other site, to explain what it all meant.