Air charge temp sensor

[turbo Scamp]

Do you guys think that there would be any gain from moving the air charge temp sensor from the intake manifold and placing it in the intercooler plumbing just before the throttle body. The stock location on the 2 piece intake seems to heat sink pretty badly. Especially the aftermarket ones that all seem to be metal as opposed to plastic like the OEM ones.

I assume that the air charge temp sensor affects fueling and timing. To what degree, I don't know.

My theory is that if it was moved to just before the throttle body, it would read cooler (closer to actual temps.) and thereby maybe allow for more fuel and less timing pull.

Any thoughts?

- Bill

[BadAssPerformance]

I think your theory is correct in what it would do with the location change, but I'm not sure that would make any more power since all of the fuel and spark curves are calculated based on the stock location.

If you want to add a little more fuel in a similar manner you can switch to a 180* thermostat from the stock 192* one.

best way to tune fuel is with an adjustable pressure regulator :thumb:

[CSXT802]

You want to know if this makes a differance.
http://i51.photobucket.com/albums/f373/brouss29/DSCF0082.jpg
http://i51.photobucket.com/albums/f373/brouss29/DSCF0083.jpg

I can't say it's the only way my car has ever had one.:p

[Frank]

since all of the fuel and spark curves are calculated based on the stock location.


Well said!

[turbovanman²]

Paul at TU told me moving it plays havoc with the programming but hey, you can try it in the stock location, then after a while, move it to the IC piping and see what happens, :thumb:

[MiniMopar]

...and the stock sensor is measuring the temperature of the manifold casting, more than the temperature of the charge.

[turbo Scamp]

... since all of the fuel and spark curves are calculated based on the stock location.


The spark and fuel curves are also based on using a 192* thermostat and a stock FPR. I already have the 180* 'stat and an AFPR. My thought was that moving the charge temp sensor would have a similar effect as changing those. More fuel and less timing pull.

I think I need to wait until I get a scanner before moving it though. Especially if Paul from TU says that it can play havoc with the tables. Without a scanner, I am shooting in the dark anyway.

Thanks for the input,

Bill

[turbo Scamp]

You want to know if this makes a differance.


I can't say it's the only way my car has ever had one.:p

That's exactly what I was thinking about doing. Too bad you dont have before and after experience on that.

- Bill

[turbo Scamp]

...and the stock sensor is measuring the temperature of the manifold casting, more than the temperature of the charge.

That's the thing that got me wondering about this.

Do the electronics think that they are reading charge temp., when they are actually reading manifold casting temp.?

Would the electronics "make better decisions" if they were seeing charge temps. that were closer to actual?

or...

Are the tables written to take the heat sink into account?


The below thread also has me thinking that this would be a good mod.

http://www.turbo-mopar.com/forums/showthread.php?t=4963

[MiniMopar]

It is safe to say that the calibration is setup correctly for whatever setup it was originally calibrated for. The stock sensor was plastic, which helped reduce some of the conduction from the casting to the thermistor inside. Still, it was tweaked for a particular engine for thousands of hours, probably.

Also, the mount of fuel that the CAT sensor can effect is rather small. So moving it to a position that will cause cooler readings will add a small amount of fuel...but not much. A lot of the fueling changes comes from the coolant temp sensor, which is why they could eliminate it completely from the Turbo I setup. They could predict the charge temps based on the coolant temps, since there was no IC. This is different from the TBI setup, since the TB is more isolated from the manifold. They need to know the temperature of that air to figure out how well the fuel is going to atomize.

If you ever hook up a scanner, watch the coolant and charge air temps. On my 87 T2, they tend to track each other. Not at the same temperature, but they both go up and down around the same time. I was expecting the CAT to go down when in motion, but it didn't really (maybe a few degrees). The 2pc intake does put the sensor in a sub-optimal location, though.

[turbo Scamp]

Dang it, I wish I had a scanner. I would love to move the sensor and see the IAT sensor temps actually start at a lower baseline. Not having to cool the sensor first due to heat sink. I am thinking that even though it only has a small affect on fueling, every little bit helps.

It just looks like the stock location is a poor design, to me. Thanks for the insight.

- Bill