IAT - What's too hot?

[ViperGeorge]

I've searched and read a bunch of threads concerning Intake Air Temp. Mostly some good info on Gen2 cars with Roe Superchargers and VEC3s. I couldn't find very much though on Gen3 cars with Paxtons.

My Gen3 has a Paxton and a PLX gauge capable of reading the Intake Charge Temp from the PCM's OBDII stream. The IAT sensor on a GEN3 Paxton is after the supercharger so it is reading temps of the compressed air. I believe the PCM will subtract timing and add fuel (to help cool the engine) after a certain IAT temp is reached. You can feel that the car is not as lively as it gets hotter. Question is at what temperature does the PCM do this? The other day I was running the car on the track at NJMP. It was a fairly warm day, in the 80s ambient. IAT was reading 123. Is that hot? At what point should I bring the car off the track and let her cool down?

 

[ViperGeorge]

What goes bump in the night? Not this thread, its daylight.

 

[plumcrazy]

might wanna call one of the paxton tuners for the info. DC, woodhouse, DLM etc...

 

[mjorgensen Woodhouse]

If you don't have a SCT tuner that will compensate for the overactive catalyst temp protection feature (most prevalent on the 06' cars) you will get serious decreases in power when the cats get hot. The temp of the cats when too high will trigger a massive addition of fuel to cool the cats down. They do this for cat longevity and when you remove this capability just be aware that the life of the cats is compromised.

I've searched and read a bunch of threads concerning Intake Air Temp. Mostly some good info on Gen2 cars with Roe Superchargers and VEC3s. I couldn't find very much though on Gen3 cars with Paxtons.

My Gen3 has a Paxton and a PLX gauge capable of reading the Intake Charge Temp from the PCM's OBDII stream. The IAT sensor on a GEN3 Paxton is after the supercharger so it is reading temps of the compressed air. I believe the PCM will subtract timing and add fuel (to help cool the engine) after a certain IAT temp is reached. You can feel that the car is not as lively as it gets hotter. Question is at what temperature does the PCM do this? The other day I was running the car on the track at NJMP. It was a fairly warm day, in the 80s ambient. IAT was reading 123. Is that hot? At what point should I bring the car off the track and let her cool down?

 

[plumcrazy]

Another reason to ditch cats on a SC car.

 

[vpower01]

Hehe what he said.

 

[ViperGeorge]

Mark, Thanks for the info. How does the PCM measure Cat temperature? I have Random Tech high flows and a Corsa exhaust on the car. Does the PCM somehow figure this out via the O2 sensors? Or does it extrapolate from IAT? If the latter at what temp what it begin to add fuel? I am running all 4 O2s by the way.