IAT sensor location on S/C system
 

Where is your IAT sensor located?

I am gathering parts and information on my planned powerdyne S/c install and there seems to be lots af variation in the location of the IAT sensor. I see many pictures with it located after the supercharger. This makes no sense to me. Everything I read and know is that this sensor should be before the supercharger. There it will read a stable intake air temp. With it located in the s/c discharge tube it will see huge swings in temps from 60 to 160+ degree temps. This will mess with the computer and tune and will run poorly. With high IATemps the computer will add fuel and pull out timing. This is not how to accomplish this.

Any comments or thoughts?

Its been my experience that you want it after the sc so the computer sees the rising intake temps. under boost you can see 200* intake temps, you wouldn't want the computer reading before the sc if its 40* out. The computer will add a bunch of timing thinking the air in the motor is cold and that's when detonation occurs


I switched to turbos years ago so this may have changed but when I did play with superchargers, powerdyne was know for making junk. Maybe they cleaned up there act, some one else can chime in there

What is computer range for the IAT sensor, will it even range to 200 degrees. Does it react fast enough to make the timing and fuel changes? It makes more sense to tune it properly and use the IAT for true stable intake temps.

To be honest I don't know the range of the stock sensor. I know in my 92 mustang would go to 220. I use the stock sensor placement on my truck but I also have an ic so even under boost air temps are still right around ambient

your thinking is flawed, you want the ECM to see the increase in charge temps to keep from cooking a few pistons

exactly.

for example, i used to run methanol/water injection on my stang when it was supercharged. the tuner programs the computer to run X amount of fuel and X amount of timing at wot AS LONG AS THE TEMPS STAY BELOW A SET NUMBER...SAY 120*. the methanol is about 112 octane and cooled the air temps so i could run less fuel from the injectors and more timing. when i floor it, if the meth fails to spray for one reason or another the computer would see intake temps go above the safe point of 120 and automatically dump fuel and pull timing to make up for the meth thats not spraying, in order to save the motor. in other words, without the computer watching intake temps when under boost and changing the tune accordingly, the motor would have blown

so with that said, IAT sensor after the supercharger

All the s/c and turbo systems I have had or seen all put the IAT before the s/c intake. You build the tune correctly and don't use/reley on the IAT to add fuel and pull back timing, that is what the tune, knock sensors, O2 sensors are for. This is the only place where I see the IAT sensor after the s/c. Using the IAT and increased heat to correct your tune is just trickery and not the halmark of a good tune. Maybe everyone else is wrong?

Maybe where the confusion is, Does the lightning have 2 IAT sensors? One before and one after the s/c? I am talking about a system that only has one IAT.

My Roush IC Supercharger has the IAT located in the number 5 intake runner after the supercharger. I dont think Roush would put it there if it wasnt needed. Once you start running higher boost levels the intake air heats up real quick and you need to know what it is so the computer can react accordingly. Think of it has your home A/C thermostat for it to work properly it is mounted inside the house not outside. Same with a supercharger you want the iat to read the air temps that are important which is after the supercharger to make the adjustment that will benifit the motor.

The iac belongs in about the same location as where it was located from the factory.

The pcm will start pulling timing ~ 150* iat.

Here's mine - iat rh side, meth lh side of pic. The meth stream hits the iac in this config.

https://www.f150online.com/forums/me...7-dscn1325.jpg

Interesting, I have just never seen it done that way. Thanks for the info.

Not trying to argue but I have never seen it any other way them after the sc.

Look here at Vortech install manual-

http://www.e90post.com/forums/attach...1&d=1318613959

And the by-pass valve hose is well away from the MAF sensor to avoid the 'backwash' effect.

looks like some one just penned that in.

Yea I did the red pen.
go to http://www.vortechsuperchargers.com/...0Ford%20Trucks
and click on 1997-2001 4.6/5.4L and go to page 18 or 26 of 28 in the pdf.

I believe the Procharger instructions had the iat pre blower also, but it is common to change them to post blower.
We know that the blowers make heat, so the temps pre are going to be too cool and the temps post will be more accurate.
Good pics, showing the bypass routing and air feeding directly into the impeller.