spectacle

My AP1 has the stock IAT located in the intake manifold. As recommended by Hondata for the Kpro upgrade, I also swapped the IAT sensor out for part number 37880-P05-A00 (not sure what car it comes stock on). I've run it like this for 3 years now, and I've always had problems with IAT's coming down to a resonable level after heat soaking at a light or idling otherwise. Another example is during a highway pull, after letting off the IAT's seemingly skyrocket (due to the closed throttle) and they take forever to come down, if they do at all. My sensor is being moved to the charge piping, which I'm told will eliminate this issue.

Now, I've heard lots of people mention how slow the stock IAT sensor reacts to temp changes and the best thing to do is to switch to a GM unit. Of course, that can't be easily done with Hondata (Kpro or Flashpro) because they don't have the necessary scaler adjustments for a different sensor.

What I'm looking for is a tech discussion about the IAT sensor, its purpose and optimal location. Here's what I know:

Stock IAT & location
Upside: you get the most accurate representation of the air temp right before it goes into the cylinders
Downside: the sensor gets heatsoaked VERY easy because of its location on the aluminum intake manifold. Also (alleged) slow response

Charge piping (Stock IAT)
Upside: not susceptible to heatsoak
Downside: requires extending wires, new mount to be welded on the charge piping, and creation of custom block off plate for stock IAT location on intake manifold

GM (or other) IAT sensor
Upside: faster response
Downside: not compatible with stock or Hondata ECU systems (need AEM, Haltech, etc)

How important is the response time of the IAT? How much slower is the stock sensor compared to the GM? I said 'alleged' above because I haven't verified the response time difference between the GM and stock sensors. Also, a faster GM sensor doesn't necessarily mean the stock sensor is 'slow', just that the other is faster.

Let the discussion commence.

9krevvin

Very interesting subject. I personally think the nest route would be to move the sensor to the charge piping and block off the intake. That way there would be no heat soak. With the GM sensor you might get a false reading if not properly calibrated.

camuman

Mine stays in intake mani. As long as the iat correction tables are tuned for its location no need to move it.

Temps skyrocket cause when u decel no air is coming in and it's hot in the oven.

spectacle

That's what I thought too. But the correction tables are there to correct air temp changes related to the environment, not heat soaked induced air temp changes. When the temp reading is falsely high because of heat soak, you're not really compensating for the correct parameter.

s2konroids

The IAT you mentioned is calibrated right due to the heat soak issues - i presume it reads lower than the stock IAT?

I'd keep it where its at otherwise you are getting a fake reading (so to speak) surely when entering the combustion camber its hotter than the IAT reports, i'd rather be on the safer side but i can understand your issues with it, mine is located in the intake manifold and is the stock IAT, I've seen it before as high as 140F!, i cant see why it would be slow to respond other than the material its made out of.

There's not a lot you can do about it, however i made a custom intake like a snorkle for my CTSC+AC and it actually helps to reduce the temperatures quicker - not a massive difference but never the less it made a difference

9krevvin

AP1's were the only cars to have the IAT sensor in the intake manifold. The AP2's were in the intake piping. I think that if Honda decided to change it , it had to be for a good reason. I'm sure Honda probably changed it due to heat soak factors? ?

spectacle

I don't think it reads lower per se. I'm guessing that the stock S2k IAT is mechanically different than the sensor they recommend (which is most likely the OEM sensor for the RSX) which would skew the IAT readings if the sensor isn't changed.

How is moving to the charge piping a fake reading? If anything, I think its the best place to get the most accurate reading of the actual air temp.

camuman

It was moved in 06 when s2k went dbw.

spectacle

Exactly. I'm thinking Honda realized the postive effects of having the sensor that close to the head weren't worth the inaccurate readings they were getting in certain situations.

s2konroids

'Fake' wasnt the best word, its not going the exact same temperature as it passes through is what i meant - however thinking about it, its negligible. I'm well aware that Honda moved it to a better place, I have contemplated moving it myself but I only run a GEMU - I'd be happy doing this with a DTA standalone which i tuned but had to sell for cash.

Why not leave it where it is and experiment with a snorkle/cai type thing and do some logging?