Alpha-N is also sometimes called “TPS maps” because the only sensor that is used for determination of fueling is the Throttle Position Sensor. (And measured RPM, or how fast the motor is spinning) Fuel and timing requirements for the engine are expressed as a function of RPM and TPS.

Right ? Ok thank you

No. Exactly why I hate this thread and I hate the kind people who are argue about how great mafless is... since it is very likely they are also clueless.

Google speed-density.

And, if you bothered to actually read the rest of the thread, you would have noticed mention of adding a real MAP downstream of the TB and using it to generate a load measurement in the ECU.

This seriously cannot still be debated, can it?

Mafless is a dumb term that someone else started, so it stuck.

Disconnecting the MAF on a system that uses the MAF as it's primary load input is stupid, end of story.  You're taking away the one thing that lets the ECU accurately see the air mass entering the system and derive load from the transfer function (MLHFM).

Once the primary load input is removed, the ECU which can no longer see what is going on fall back on limp home tables which are a function of TPS vs RPM also known as Alpha-N, this is at the most basic level and combined with other tables to account for (limited) basic load calculations.  IAT/MAT sensor is in the manifold and is a correction after the fact.  The pressure sensor (people here call it a "MAP" sensor which it is not) is PRE-THROTTLE.

If you understand the consequences of tuning Alpha-N style with boost (or even NA to a point) you generally will understand why it is the last thing you want to do vs having an actual load calculation (Speed density) or sensor (MAF) if you have a choice.

There is no Speed Density available on most ME7.1/7.11/7.5 (some ECU version have MAF + SD, or just SD - I'm not sure what ME version they are), the code is physically missing and can not be just "turned on" so the only thing this thread is really about is how to disable the ECU's warning/limit tables and force the ECU to stay in limp mode to allow for limited tuning known as Alpha-N, and as such is a dumb thing to do.

If you don't exactly know WHY that is, you should seriously consider learning so before switching to this method.

I don't understand why people can't accept the peoples that wanna go mafless or wanna learn how to do the hack for limp, brake 50/50 and esp instead!

It seems you (all)  take this something like to much personal... but it's not... and you  have to respect other people's thoughts.

When throttle is WOT, isn't the pre-throttle pressure sensor very close to being a MAP ? If so, then any driving conditions below WOT, where the 'MAP' is not really a MAP, are less important to MANY people, ignorant or not.

Do you also look down on old school muscle car ppl when they have access to all the EFI systems but choose to stick with carbs? Is there an ignorance at play there as well?

edit: my point I tried (horribly) to make with that last statement is that cars were tuned without all these sensors in the past and were hailed as perfectly fine. Mechanically tuning a carborater and distributor can be just as fun as hitting keys on a keyboard. The act of tial and error tweaking 'backup' maps can be considered a combination of the two.

Different ppl have different experiences that mold their motivations. Consider the ppl (and there are plenty of them out there) that have had bad experiences with replacing sensors after sensors. Sure you could bark at them saying they just didnt find the root cause, but their perception has already been molded. You can't expect them to weight all their previous, personal experienced against words from a screenname on a forum and be converted right then and there. Some are willing to run on blind maps just to stay away from fragile (in their minds) sensors.

I run a MAF. But prj has given enough hints that make me interested in rerouting/copying udslsum_l into uhfm_w. Still alphaN but avoids all the limp headaches. Then just need 2nd map (3rd for me ) sensor and then make it's voltage reading feed uhfm_w. <- this is the secret . sauce. Or is it as simple had changing maf connector to map connector and Bob's ur Uncle? I know I doing tomorrow.

You're wrong... there is nothing personal at all about this. The only reason you would use that an an argument is because you don't understand what maffless means and how much worse it is vs the correct options.

No one here cares if you do or do not hack the ECU into limp mode, believe me.

Typically one wants to set up controls based on the direct variable of interest (mass air flow), and resort to a secondary variable (manifold pressure) or (God forbid) a tertiary variable (throttle plate angle) only if there's a compelling reason to do so, e.g., sensor technology just isn't there, maybe response to transients isn't great, something like that. 

Purely philosophical argument; some carbs (Dellorto's!) are cool just because they are (and make great throttle bodies for home-brew FI, best of both worlds).  Depends on the intended character of the vehicle in question.