[maxi-overdose]

iTrader: (3)

I started a thread about the power loss I felt when I am boosting

http://forums.maxima.org/showthread.php?threadid=193850


when I tried to trace back on what was done that changed the car. I remembered that the CAI was installed and the air temp sensor is no longer in the intake pipe. I went back and took a look at my car, it was sitting behind the battery and it did not get much cool air flow. So I zip-tied it to the battery cable and run the car again. It seems that power loss is not noticible.

I remember Jay25 told me that playing around with this sensor can change the car's performance.

hmmmmmm..........

Stephen Max

iTrader: (59)

According to the FSM for my 95, the intake air temp sensor is used only as a cross-reference for checking other sensors, such as the coolant temp sensor, and does not provide any input to the ECU for closed loop operation. Besides, you produce boost at WOT at which time the ECU reverts to preprogrammed fuel mapping and any input from sensors is ignored.

But here is something interesting. The FSM showed an electrical resistance vs. temperature chart for the iat sensor. I had an extra sending unit for my Autogage oil temp gauge, and I measured its resistance at four or five temperatures, and guess what, the resistance vs temperature curve is exactly the same for both!

What this means is, if you have an oil temp gauge already installed, then it is an easy matter to disconnect the harness and jumper the iat sensor over to the oil temp gauge to get an analog readout.

I did this shortly after installing my supercharger, because I was interested in finding out how hot the intake air got from being compressed and also from crossover pipe heating due to close proximity to the front exhaust manifold. I found that on a 70F degree day, the intake air gets to slightly above 150F after several 7-8 psi runs.

Once I get my CAI installed, I'll retest and see if there is any difference.

turbomax97

iTrader: (6)

So In English, for guys like me where the sensor is hanging there, is it worth installing it in the pressurized air pathway?..

Stephen Max

iTrader: (59)

Nah.

[maxi-overdose]

iTrader: (3)

if it is used as a cross-reference, can that affect the result from other sensors that tries to use this air temp sensor as a baseline? But if the ECU overwrites the fuel mapping at WOT like you said, this sensor does not play any role at WOT.

Quote:

But here is something interesting. The FSM showed an electrical resistance vs. temperature chart for the iat sensor. I had an extra sending unit for my Autogage oil temp gauge, and I measured its resistance at four or five temperatures, and guess what, the resistance vs temperature curve is exactly the same for both!

What this means is, if you have an oil temp gauge already installed, then it is an easy matter to disconnect the harness and jumper the iat sensor over to the oil temp gauge to get an analog readout.

I am a bit lost here....so you are suggesting we can use a tranny fluid temp guage to measure intake temperature??

Quote:

I did this shortly after installing my supercharger, because I was interested in finding out how hot the intake air got from being compressed and also from crossover pipe heating due to close proximity to the front exhaust manifold. I found that on a 70F degree day, the intake air gets to slightly above 150F after several 7-8 psi runs.

Once I get my CAI installed, I'll retest and see if there is any difference.

I am ruling out the iat sensor as the cause of my power loss. I really dont have a clue now. I tightened my BOV and re-route the sensor to the front and the problem seems to be corrected. I will find out this afternoon. boost time!

Y2KevSE

iTrader: (13)

Maybe it's time to dyno.

Stephen Max

iTrader: (59)

The iat sensor is used to determine if other sensors are functioning normally, as far as I can tell from reading the FSM. The FSM does specifically say that the iat sensor is not used to control engine management.

Yes, you can use the iat sensor as the sending unit for an Autometer oil temperature gauge. It is calibrated exactly the same as the Autometer sending unit.

Tightening the BOV does increase part throttle power, since it reduces the amount the BOV opens at part throttle. So instead of getting, say, 10 inches of vacuum at part throttle you might get 5 inches. This results in slightly more air to the engine and thus more power. The trade-off is increased susceptibility to compressor surge if you're too aggressive with the preload screw. But there's a happy medium in there somewhere.

[maxi-overdose]

iTrader: (3)

it is....it is, boss.

have you decided when we should drop by ATP?