I seem to notice a large number of people always wanting to convert their SD type EFI over to a MAF type EFI system, can anyone tell me the logic behind this, am i missing something on the MAF sensor that makes it worth the cost and work involved in the conversion?
I have always known the MAF sensor to be one of the most delicate sensors on the engine because of its internals and i have seen many a MAF sensor fail, i found this comparison of a SD system to a MAF system online (oldfuelinjection.com), i had a little fun with it and the text inside the "quotation" marks are my response to the differences, enjoy..

~Mass Air Flow~
MAF sensor can impede maximum inlet airflow.
"that's fixable but costly"

Pulsating inlet airflow characteristics trick MAF sensor.
"hey, bonus points for SD"

Program calculations required by boosted applications will not be sensed.
"i thought that job was for the Boost sensor"

Doesn't react to throttle change as quickly as Speed Density or Alpha-N.
"damn, more bonus points for SD"

Can compensate for changes in altitude and ambient air temperature.
"not a big deal if you live at sea level but has its place in the mountains"

Can compensate for aging engines with diminished performance.
"true, but this would equate to very little adjustment"

Does not rely upon other sensors to make general fuel ratio calculations.
"true, but you are relying on a rather delicate/pricey sensor to make A/F mixture adjustments"

Air mass vs engine temp in main calibration table.
"knowing how much air is entering the engine does allow for more accurate A/F adjustments"

Works well with mild performance engines.
"suits me fine but the pony boys may not be so enthused"

Works well on engines with mild inlet airflow characteristics.
"true, but not so good on engines with harsh airflow characteristics, do some research on Laminar Airflow and it's relationship with the MAF sensor"

Engines With high emissions and economy demands.
"OBD II and the MAF sensor, a marriage made in heaven"

versus

~Speed Density~
Can't compensate for changes to engine.
"au contraire mon ami, the ECM can be reprogrammed to compensate for any changes for under $300 aka TwEECer"

Aged engine losing efficiency over time is not sensed nor compensated for in the calibration.
"i think i covered that with changes to engine"

Oxygen sensors can fix fuel ratios in closed loop, but not ideal to rely upon them.
"this was before we discovered wide-band oxygen sensing"

Does not react to throttle change as quickly as Alpha-N.
"who cares, Alpha-N is designed for race engines"

No inlet sensor restriction.
"oh, thank god"

Calculations required by boosted applications can be made.
"bonus points for supercharger, turbocharger crowd but the N/A (naturally aspirated) crowd could care less"

Manifold vacuum vs engine temp in main table.
"now you know, the MAP sensor is dominant in SD"

Can be somewhat stable if oxygen sensors are working correctly.
"modern wide-band O2 sensors are very accurate"

Low power docile engines.
"SD got a bad rap because people were using camshafts with too much overlap which killed the vacuum, not the SD's fault as it relies on vacuum or MAP to make A/F adjustments"

High performance engines with harsh inlet airflow characteristics.
"don't tell the MAF sensors, they will be so jealous"

 

For a stock set-up, speed density is great. It isn't so great for power upgrades. SD uses set tables based on engine vacuum. It can adapt some to things such as better exhaust and intake, but when you start adding larger camshafts which cause lower vacuum and better flowing heads, the SD can not adapt which causes the air/fuel ratio to be out of whack.
The MAF measures actual airflow thru the meter to determine the air/fuel ratios and other perameters.
I converted my 88 Mustang to MAF. My current set-up only holds about 14" of vacuum. With SP, it would be running way to rich.

 

Has anyone ever thought of using or used a vacuum amplifier/reservoir to smooth out and increase the vacuum signal to the MAP sensor ?

 

i do not think that they operate fast enough to keep up with changing conditions.