Curious about MAF Voltage breakpoints on 2005-2010 Mustang GT

[Black_Sunshine]

I'm currently in the process of copying over parts of later model 4.6l 3v stock tunes to my 2006 Mustang GT to see if there are any improvements that Ford made that would be easy and safe to apply. One thing I've noticed is that the voltage breakpoints on the MAF Voltage vs. Airflow chart have shifted over the years and I'm curious as to why that is. In comparing my 2006 to a 2008 Bullitt tune, there's a good handful of breakpoints that have shifted a decent amount.

By the time 2010 rolled around there were a few more minimal shifts but not as large as between 2006 and 2008. I've applied the 2008 Bullitt table breakpoints and done a proper calibration with wideband and all is well but still curious. Even if you take the Bullitt out of the mix because of it's factory CAI, 2006 and 2010 are significantly different and as far as I know basically share the same factory intake. First image is 2006 and second is 2010.
Screenshot 2024-12-04 125831.pngScreenshot 2024-12-04 125917.png

[B E N]

Tune this by using LTFT+STFT and a log. No reason to use data from the wrong car. There are lots of reasons these would change with time.

[Black_Sunshine]

I've already gotten everything dialed in with STFTs at part throttle and a wideband I popped in one of the rear O2s temporarily for WOT tuning. Every cell is within less than 2% error at this point. I'm just curious. The MAF is the same part number across 05-10 but a handful of the breakpoints have shifted down by a good couple mV over the years so my reasoning is that maybe Ford decided over time that it was important to have more granularity in the lower-to-midrange of airflow readings, possibly for smoother everyday driving?. Whenever the points are farther apart the PCM has to interpolate or average the values in between. Sorry, I'm just the kind of guy who always has to ask: "But why"

As far using the "wrong" data or car, the 2008 Bullitt has the exact same hardware as an '06 besides the addition of a factory CAI. I've had 0 problems since I manually copied over all the settings and tables.

[B E N]

Like you said the Bullit had the FRPP power pack CAI, which means all of those values are setup for that exact intake, not a stock intake... so unless you are using that specific CAI it is the wrong car. The primary things that will effect that table are going to be tube diameter and intake design. It is possible Ford increased the granularity at the bottom because they realized they were not getting anything near the top and it cured some drivability issue with that particular intake. It is possible that it is arbitrary, IE they did it because they were redesigning the intake and someone else came up with the numbers, whatever flow bench they used to test the intake had a different scale, on and on, who knows. You can set them to whatever you want, if you believe having more resolution in a particular area is going to improve your driving experience then give it a shot, it's unlikely to harm anything if you set the values to something reasonable and tune properly.

What are you after exactly? If you are looking for power you should be looking at timing and an octane increase.

[Black_Sunshine]

The idea was, while I'm learning this stuff from the ground up, to grab some initial easy gains in performance off of a car that was tuned by Ford engineers to have more performance than my car but mechanically is essentially the same. Even differences like the IMRC plates becoming integrated into the manifold doesn't happen until 2009 so a 2008 Bullitt tune is technically plug 'n play besides the CAI which is something you'd want to calibrate for yourself anyway. I could be wrong but I haven't noticed any ill effects so far even though some differences do seem weird like the stock manifold volume being set to 10.90l vs 9.81l in the Bullitt stock tune.

Dialing in the timing for 93 is next on the list! It's also a lot of fun to play with the torque management to find one's own "perfect" pedal feel.