IAT sensor location questions

[BigBlockOlds]

As I understand it, the best place for the IAT senor is in the intake manifold itself or wherever it will see the actual air temperature that the engine sees. Probably more critical with supercharged/turbocharged engines but I will be installing mine in the intake as well.

My question is whether or not the sensor probe needs to be directly in the path of the air? Or if I weld in an aluminum bung, and it sits a little further back, will this still read the air temperature correctly?

Thanks,

[parsonsj]

Andrew,

Temperature is different than pressure, in that it takes time for it to move from one area in a plenum to another. (pressure does too, but the time variable is short enough to usually safely ignore) How much time, and what kind of variances you would see are going to be complicated and will likely require lots of experiments.

We need more information: I'm trying to understand where you would put the sensor that it wouldn't be in the path of the air flow, or at least to one of the cylinders.

jp

[Steve1968LS2]

Well GM integrated the IAT into the MAF on the LS2 series and newer of engines. I don't think you would want it too far from the intake, but in reality the temp would change much, if all, from the MAF to the TB.

If you mount the IAT in a metal intake or in a metal bung couldn't you have a problem of that metal heat-soaking and throwing off the reading of the IATS?

[Z-man]

My question is whether or not the sensor probe needs to be directly in the path of the air? Or if I weld in an aluminum bung, and it sits a little further back, will this still read the air temperature correctly?

Thanks,

I'll bet you want to do this to smooth out the air flow. IMO, you should be fine to set it back a bit. The turbulence will ensure that you get a good reading - the air temp isn't going to change a hundred times a second anyway.

[BigBlockOlds]

Yes, I was partially concerned about having a probe sticking into once of my intake runners and what that might do to the air flow into that cylinder. Probably nothing really but I wasn't sure.

Of course that is if I just drilled and tapped the intake. If I welded in a NPT bung, then I don't know how far the probe would make it into the manifold.

My manifold is an Offenhauser Super-Sonic and just about the only place I can put the sensor is in one of the runners going to the #7 or #8 cylinders. I'd like to put it in the side of the plenum but there is a lot of material there and the probe would never reach the air stream.

Thanks,

[Z-man]

If this is a street vehicle, I assume you're going to run air filters. Can you find a place to put the IAT on the lower side of whatever holds the filters? (Like the bottom of an air cleaner.) I'd guess that is a better place and you wouldn't have to take a risk messing up that manifold. (You could almost scotch tape it to the air cleaner and get the same results!).

[MonzaRacer]

In all actuallity i would run it as far away from the engine as possible in theair intake tract.Reason is the engine assimilates outside air to engine temp.
We worked over an older Ta with TPI and we moved the iat out in front of the car and the engine really did like what it saw, The car picked up 2 tenths and the mpg went up too.
BUT this is a trial and error process. Having it in the intake will have the computer trying to evaluate hot air over cold air. The iat is attempting to provide the calibration algorythum with a variable to compute fuel integration numbers.
In all actuallity I would be looking for 2 or 3 places to mount it and try it for different tunes.
The big trick is what computer are you using and for what purpose.
Also if its an oem style computer (ie GM) it wwill throw an IAT code (ie like reading too low then you would need to moveit into a warmer areas slightly.
BUT I have never had one do that when moving the IAT.

[BigBlockOlds]

Thanks for the suggestions. I'm going to have an aluminum bung welded as close to the plenum as I can for the IAT sensor and will also try putting it in the base of the air cleaner to test which works better with my setup.

I really can't get it as far away as some can with the later model fuel injected cars that use an intake tube. What I have is a 1600cfm dominator throttle body and just a standard open element air filter/housing that will seal to the underside of my W-30 hood.

So its either in the intake itself or the air cleaner.

As for the computer, I'm using a Megasquirt V2.2 with full fuel and spark control.

Thanks,