Logging IAT2 on Roush Phase 2 Car - Possibly With OBDLink MX+?

[SplawnDarts]

I'd like to log IAT2 on my 2019 5.0 car with a Roush phase 2 supercharger. I have an OBDLink MX+ that I could use if that would be helpful.

What do I need to do to get access to it?

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[SplawnDarts]

So far I've figured out that the Roush kit installs what they call a "Air Charge Temperature" (ACT) sensor in the intake manifold, separately from the IAT1 sensor which remains part of the MAF.

I also found the PID and a conversion formula for ecoboost IAT2 sensors:

PID: 2203ca
Equation: (A-40)*1.8+32

The equation sort of looks like Celsius to Fahrenheit conversion, but not quite. Not sure what they're doing there.

I know I've seen people reporting Roush IAT2 values, so hopefully someone can help with how they did it.

 

[hlfbkd420]

Install OBDLink and then scan your car with the Mx. it will ask if you want the ford specific package. Say yes and download. Add a dashboard and have it set to iat2.

 

[SplawnDarts]

Thank you mucho. I'll try it tomorrow. Do you know if it reads true to temp? I've seen some vague comments about inaccuracy, but I'm having a hard time figuring out what to believe.

 

[hlfbkd420]

Thank you mucho. I'll try it tomorrow. Do you know if it reads true to temp? I've seen some vague comments about inaccuracy, but I'm having a hard time figuring out what to believe.

The polling rate is a little slow (about 1 second between logged info) but it seems accurate. From what I understand, the IAT2 temp is *inferred* but still pretty close. I will tell you this, at 160 degrees the throttle blade will start closing on the Roush setup. Phase 1 and 2 are both the same way. I have seen pulls at the strip where at half track the TB is at 60% and boost is around 3-5psi.

Most of the time for me, IAT2 is about 35 to 50 degrees over ambient depending on the temp.

 

[SplawnDarts]

I very much appreciate your help, but you mention several things I've also seen in other threads that have me confused:

1) The Roush kit has an additional sensor that's installed (section D, step 11 of the installation for anyone following along) - why would anything be "inferred" when there's a sensor right there? Timing (and throttle) decisions have to be coming from that sensor, right?

2) People are reporting large differences between ambient air and IAT2. This seems highly suspicious (especially for phase 2) barring a heat soak situation. I'm wondering if these various tools pull the right PID, but are using the wrong formula for the Roush sensor? I guess the way to test this is to look at the temps right at startup with a cold engine and coolant. If there's still a big gap between ambient and IAT2 even though the air is passing though a cold intercooler, we know IAT2 is not reading right.

 

[hlfbkd420]

I very much appreciate your help, but you mention several things I've also seen in other threads that have me confused:

1) The Roush kit has an additional sensor that's installed (section D, step 11 of the installation for anyone following along) - why would anything be "inferred" when there's a sensor right there? Timing (and throttle) decisions have to be coming from that sensor, right?

2) People are reporting large differences between ambient air and IAT2. This seems highly suspicious (especially for phase 2) barring a heat soak situation. I'm wondering if these various tools pull the right PID, but are using the wrong formula for the Roush sensor? I guess the way to test this is to look at the temps right at startup with a cold engine and coolant. If there's still a big gap between ambient and IAT2 even though the air is passing though a cold intercooler, we know IAT2 is not reading right.

Without looking at the manual you may be referring to a sensor that was recently added. Not sure if it’s the same sensor you are referring to but a lot of p2 kits didn’t have a sensor that later buyers say they have. Roush has said the sensor isn’t necessary to some users and mainly monitors the temps more accurately to control the Heat Exchanger fans.. Hence why I assume on some cars it is inferred.

as for iat2 temps, mine is ambient during a cold start in the AM but quickly gets to 30 or 40 above ambient. Cold starts in the afternoon in AZ in 115 degree heat can mean heat soak very quickly.

 

[SplawnDarts]

OK, if it's starting close to ambient that seems right - the SC heats the air, but the intercooler is still cold so it should come out near ambient in the end.

 

[SplawnDarts]

So first off, I want to thank you because your information worked. I attached the MX+, paired it to my phone, installed OBDLink, connected them, installed the 2019 Ford specific stuff, and the created a dashboard with "intake air temperature, bank 1 sensor 1" and "bank 1, sensor 2" and sensor 1 was clearly cold outside air, and sensor 2 was higher and went up with heat soak and/or driving. I'm going to assume this is IAT2 unless someone tells me otherwise.

I still need to look at them when the engine is off/cold to confirm that the scale on sensor 2 is not bogus. Sensor 1 I know is right because I can compare it to IAT on the dash and the outside air temp, and they're all the within a degree.

I did find this line in the manual: " Air Charge Temperature (ACT) Sensor (From the factory, this function is integrated into the MAF sensor. With this kit, a separate ACT sensor is installed into the intake manifold)". That seems to clearly state there IS a sensor, which matches the installation instructions and what it looks like under the hood.

It's gotten cold here (28F) and I'm on summer tires that felt like rocks, so I drove like grandma but IAT2 seemed to stabilize at about 90F. Since there is a temp sensor for the heat exchanger, I'm guessing it's bypassed or the pump's off or both when it's super cold, so the big gap probably doesn't mean anything. When we get a warm day I'll do some pulls and see what I see.

 

[hlfbkd420]

When you add the dashboard, it should say on the gauge "intake air temperature 2". At least that is what mine says. IAT1 should normally be around ambient unless you are at idle.. then maybe plus or minus a few degrees.

In case you didn't know, you can have the car in park and hold the brakes, then press + on the cruise for about 10 seconds to turn on the HE pump and fans. Works wonders at the strip. You can do that and then turn off the car and the fans/pump will be on.

 

[Jmtoast]

I have the OBDLink MX+ and it works just fine. This kit gets super hot. Before it got super super hot but Roush has managed to get to just one "super" with the ltr.

 

[brucelinc]

I have found that in cold weather, the difference between iat1 and iat2 is larger than in warm temps. In 80-90 degree weather, I see a 35-40 degree spread. In 20-30 degree weather, it is more like 50 degrees or even more. My car does have the sensor in the HE. I also have opened up the grille where outside air is brought into the air box.

I no longer get very concerned about iat2 temps. I do live in a generally cooler climate but we do have 90+ degree days in the summer and heat index well over 100. The highest I have ever seen 1at2 temps while running is 140 and that was at the drag strip. Even when naturally aspirated, hot weather hurts performance. Since going supercharged, heat seems to have no more effect on performance than when NA. I understand that the throttle body closes at 160 degree iat2 but I have never had it that high.....with the engine and fans running. Those in hotter climates, like hlfbkd420, will likely see that happen, though. In Denver, where SplawnDarts lives, the altitude will be an enemy for sure.

I don't race my car when the temps are in the 90s. I ran at the strip when outside temps were in the mid 60s and again when they were in the 80s. The difference in ET was one tenth. I lost that much or more when NA.

 

[SplawnDarts]

When you add the dashboard, it should say on the gauge "intake air temperature 2". At least that is what mine says. IAT1 should normally be around ambient unless you are at idle.. then maybe plus or minus a few degrees.

In case you didn't know, you can have the car in park and hold the brakes, then press + on the cruise for about 10 seconds to turn on the HE pump and fans. Works wonders at the strip. You can do that and then turn off the car and the fans/pump will be on.

I took a look, and I have 8 things that could be candidates:
Intake Air Temperature bank 1, sensor 1 (6 total, banks 1 to 2, sensors 1-3)
Intake Air Temperature (C, F)
Intake Air Temperature 2 (C,F)

So far I've plotted Intake Air Temperature bank 1, sensor 1 and Intake Air Temperature bank 1, sensor 2. Sensor 1 is clearly pre-SC and reads in degF. Sensor 2 is clearly post-SC. But it also reads about 20 degrees higher than sensor 1 on cold start. I need to test this on a REALLY cold start, but it was in a cold garage overnight. Which brings me back to the question of whether sensor 2 is scaled to Fahrenheit degrees or not. I know there's a voltage to temp mapping table in the tune, and that at least Whipple messes with it. So there's no guarantee I guess.

My next step is to plot:
Intake Air Temperature bank 1, sensor 1
Intake Air Temperature bank 1, sensor 1
Intake Air Temperature (C, F)
Intake Air Temperature 2 (C,F)

all on the same chart and see how they relate.

 

[SplawnDarts]

I have found that in cold weather, the difference between iat1 and iat2 is larger than in warm temps. In 80-90 degree weather, I see a 35-40 degree spread. In 20-30 degree weather, it is more like 50 degrees or even more. My car does have the sensor in the HE. I also have opened up the grille where outside air is brought into the air box.

This is consistent with the SC cooling system being thermostat controlled in the same way the engine cooling loop is. Since there's a coolant temp sensor in the kit, I'm fairly sure it must be. Otherwise why waste money on the sensor if nothing's going to be done with the info?

 

[SplawnDarts]

I just confirmed that Intake Air Temperature bank 1, sensor 1 and sensor 2 have the same values as Intake Air Temperature (C, F) and Intake Air Temperature 2 (C,F).

So now the remaining mystery is why IAT2 doesn't read the same as IAT1 before starting a cold car. Everything should go to ambient if it sits long enough. It's possible my car wasn't cold enough - it only sat about 12 hours in a ~50deg garage. But if that's not the explanation, then IAT2 is NOT in units of degF despite what it says - it reads high by about 20deg at least at 50deg.

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