I'm no expert on EFI. But I like to be technical with only give out correct information. Usually bias'd from my own personal experience or my own personal likes and dislikes. So take what I say with an open mind. Its not always the 'proper' or only way to do something.

They way I understand Air Density vs MAF 5.0 cars is like this.

The 86 - 88 cars have 3 main components for engine management. The MAP sensor which reads manifold vacuum, the TPS sensor which read throttle position and the O2's which read oxygen levels in the exhaust. The problem with trying to modify an Air Density car is not the fact that it doesnt have an MAF. The really fast prostock guys running EFI do not use a Mass Air Meter. They use something like a FAST system which is indeed Air Density Based. But they tune their car for WOT,.. and Air Density is the easiest to tune for WOT. You set your fuel and timing tables per RPM level. Its preprogrammed that at a said RPM level it should have a known amount of air coming into the engine. The fuel and timing is set accordingly. And that is pretty much how Ford Air Density works,.. except the map sensor and O2's try to compensate some of the variables for drivability. The stock computer has a preset table it reads as the RPM's climb it knows how much air should be coming into the engine. If you alter that with a cam, larger intake and TB, and then throw headers on it so the engines breaths better,.. the computer does not have the ability to read and compensate for all of it.

With a MAF meter the computer can now adjust fuel and timing because the MAF sends voltage signals that tell it how much air is coming in. It can compensate for more variables at different RPM levels that an Air Density system is just not capable of doing.

For an all out race car,.. Air Density is cheaper and easier to tune. For a street driven car.. an MAF provides more information to the computer to adjust the engines needs. But an MAF can only read so much air before it becomes (Pegged out) voltage limited. Once more air passes through the MAF than what it can read,.. you run into the same problems that you had with Air Density.

Converting an Air Density car to MAF is really pretty easy. There are detailed how to's with step by step pictures all over the net.

What you need:
An MAF housing with a 4 pin meter set for 19lb injectors (if your stock)
An MAF 4 pin pig tail to tie into the computer and wiring harness.
And lastly you need an 89 - 93 computer. The A3M and A9L are the two most desirable. They are essentially the same thing.

The computers go for about $100.
the MAF meters run anywhere from $25 to $250 depending on where and what you buy.
The pig tail can be free if you steal it from a junkyard or $45 to $65 for ready made ones from online vendors.


I hope that was understandable in laymens terms,.. and I hope most of it was correct. Those who really know and understand this better then I do,.. please feel free to correct me if anything I said was incorrect.



Peace,..

Hurst