IAT sensor
 

Is it a measurable benefit going to a fast IAT like the one bofi sales(<2 seconds) compared to a GM sensor?

Fast IAT

My MAT Correction changes fueling by 2.5% over a 20F range. I don't think a 10 second (which I think is a marketingly large number for the GM) will see enough error in real life to move the AFR more than 0.1 or 0.2.

Also, how are they defining response time? I the most typical, instrumentation definition of response time is the time it takes a sensor to report 90% of a step change. If they are using that definition (IF), then a 10*F instantaneous change in temp, which would make about a 0.15 Error in AFR, will be 90% wiped away in 10-20 seconds on the GM. In fact, a 10 second pull is long. So you're out of boost and cooling back down anyway.

TLDR: It would not be worth any extra $$ to me. If it were the same $$, AND I knew what values to put into the MS3 calibration, then, sure, I'd go with the faster one.

EDIT: I see that they do give the calibration curve.

I zeroed out my MAT correction curve for initial tuning and that was uh..... 2 years ago? I run a little rich up top, tune on a colder day, and then only use it if intake temps get super high. Anywhere I am cruising I just use EGO closed loop correction.

All this to say, I don't really even use the MAT sensor in my tune....

MAT has value for Idle PWM initial values, even if one does not use MAT Correction for fueling.

I prefer to try to minimize EGO, except at idle, where the temperature variation of the high impedance injector coils wreaks havoc.

X_25: zeroed out MAT curve should normally result in Lean at cold MAT, and rich at hot MAT. I guess you are saying that you've tuned the "up top" when cold MAT, and let EGO pull fuel in other situations.
DNM

Yes, I tuned my fuel table in sub freezing weather so EGO would be pulling fuel when active and I just run a bit richer up top where EGO isn't active.

Is it the right/best way to do it? Not at all. But it works good enough for my needs. My overall point is that a fast acting IAT, while it would be nice, is certainly not at all nessisary.

Thanks for the input, just trying to get the last things before I get started with my MS3. I have a few other questions as they pertain to wiring and what not but have some more researching before to answer as much as I can first.

Just wanted to make sure that paying over 3x as much for the IAT compared to a GM that it wouldn't make a huge difference after seeing the threads of warm start issues. Thanks guys.