Afm Vs Map

[Akshunhiro]

If you're planning on running MAP without IAT, you're gonna have a bad time.

I'd go MAP over MAF, easier to tune and more reliable.

[R31Nismoid]

So in a nutshell, there really is no difference/benefits between running either MAF or MAP on your average 'line..other than maybe saving a few bucks

Pretty much.

[GTRNUR]

The most frustrating thing I find with MAP sensor ecu's is the lack of capability to accurately tune for altering altitudes or atmospheric pressures. I initially used an atmospheric compensated GM 3 bar sensor, and it would over compensate and run lean at higher altitudes. I've now switched to the Apxei 3.5 bar sensor and it goes the other way.

The Apexi sensor is a far better quality item for accuracy and reaction speed. I've picked up massively noticable throttle response and eliminated a flat spot that would occur during the transition onto boost. This is balanced out by the need to have a completely different map made up when I drive up a hill. The PIM value is changing near on 400-450, which is nearly 1/2 a load band cell group in the vacuum range.

This means a cruise AFR of 14.7 turns into a fat 13.x. Add to this that the air temp sensor is adding more fuel due to the air temps on the tablelands being at least 10 degrees cooler than the coast. This charactoristic is more noticable off boost than on, but I can't really say for sure as I've only driven the range once with the new sensor in the car and it was pretty much all at a slow pace. The on boost load bands change at a PIM rate of 2000 per band.

MAF sensor tunes are SO much easier to get correct, and they compensate way better at altitude as it is measuring air density/temp/volume all at once and all the time. Less drift in tune. Map on the other hand, just compensating with air air temp sensor to predict altered air density just isn't enough. The only correct way to do it would be to use a propper atmospheric pressure compensation sensor, and use the sensor data to alter the MAP sensor value by a % over RPM.