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whats important is the temperature of the aircharge entering the cylinder. not the intake tract. it is compensated for ect.
From a tuning perspective, it does not matter. The air charge at the intake or the air charge at the manifold you compensate for the difference in temp. 100 degrees at the intake is 160 at the manifold. You set the ecu to start pulling timing at 105 at the intake or 165 when in the manifold. It accomplishes the exact same thing.
 
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of course it matters. how was it determined that the temp at the cylinder is 160, but 100 in the intake?
you are saying the same thing with different words. act is compensated for by the ect.

ill choose to sample that temp as close to the cylinder as possible. you may feel otherwise. to each their own

time spent worrying about a heat soaked act sensor can be spent best elsewhere.
 

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of course it matters. how was it determined that the temp at the cylinder is 160, but 100 in the intake?
you are saying the same thing with different words. act is compensated for by the ect.

ill choose to sample that temp as close to the cylinder as possible. you may feel otherwise. to each their own

time spent worrying about a heat soaked act sensor can be spent best elsewhere.
I posted this earlier, but you probably missed it. You can easily see these differences when comparing a 93 ecu strategy to a 94 ecu strategy but youre focused on the specific numbers i posted.. the numbers i used dont matter, they are just an example.. Youre going to adjust them for your application. With the ACT in the intake, a 94 ecu starts pulling timing about 105 degrees, at the manifold in a 93 ecu its about 165 degrees (if I remember correctly). If you don't know, you can easily data log the information to determine what normal is in that particular application and then adjust based on the logs. Its not really hard to determine what a normal IAT is for a particular setup.
 

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Well I think I may have changed my mind about this again.



I just checked my sensor out and the resistance looks right but I don't have a great way of blowing air across the tip in a controlled manner while heating the body up to simulate conditions installed in the lower manifold on a running engine.

Although, one thing I noticed, the sensing element is situated pretty well away from the brass body and supported up into the air stream by tiny prongs not likely to transfer much heat. Especially when you consider how much airflow this thing probably sees. The insulating separator is plastic. It looks like a pretty good design that wouldn't heat soak much...



I watched his video and he made good points about the location of the sensor affecting the A/F ratio on warm engine restarts. Basically the sensor cools off really fast if it's located in a cold area, even if the engine itsself is still hot, so the computer commands a richer mixture as a result of seeing this cold air temp when it's not really needed. I don't really like rich starts. I would like my setup to run as efficiently as possible.

And finally, it will save myself the work of tapping or welding a bung to install it in a different location. I'm thinking it's just not worth the effort. It doesn't look like I have to worry about any great differences in readings, or at least anything that can't be compensated for in my tuning adjustments.
Remember that there is 2 different compensations in tuner studios for engine starting fuel and air temperature compensation. Engine starting is mostly based on actual coolant temp, and a small percentage is based on MAT. However, what you’ll find is sometimes the engine might need a little more fuel for a short period of time on a hot restart than you might imagine.

IMO I like to put the sensor in a charge pipe or plenum to see temps post intercooler because It gets a better representative temp on what it’s like leaving the intercooler. As I can tell you if it’s in the runner, you will start a hot engine and the sensor will be hot as hell, which won’t be indicative If the actual air temp on a running engine. I agree that if it’s compensated for correctly it doesn’t matter, but I’d rather start with the reading directly past the intercooler.
 
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Discussion Starter · #25 ·
It also just occurred to me that hot EGR and PCV blowby gasses are introduced back into the intake at the upper manifold ahead of the air temp sensor's stock location. The reading wouldn't take that temperature change into account if the sensor was placed anywhere else...
 

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It also just occurred to me that hot EGR and PCV blowby gasses are introduced back into the intake at the upper manifold ahead of the air temp sensor's stock location. The reading wouldn't take that temperature change into account if the sensor was placed anywhere else...
Egr doesn’t work with microsquirt anyways. You’re running a turbo correct?
 

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Yep, I just think that may be a contributing factor into Ford's decision for placing the sensor there.
I wouldn’t know. I can’t see it contributing that much to an increase in iat though.

I’d probably look into a catch can setup with the turbo.
 
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