88droptopgt

So what is the diff, why is the MAF better? The HP between them is the same in these cars so what is the deal?

tmajikman

do you mean mas and speed density?

vristang

Assuming the question was with regard to mas and maf...

Typically the terms MAS and MAF are used to differentiate between 2 seperate components of a Mass Air equipped car.


MASrefers to the sensor. This will be a black electronics box mounted on top of the mass air tube.
MAF refers to the housing. The housing can be found in several sizes, from several manufacturers.

The MAF should be large enough to flow sufficient air at the higher rpm ranges. The MAS must be properly matched to the MAF size, injector size, and computer being used.

The MAF/MAS/Injector/Computer combination is critical and must be correct.

jason

88droptopgt

ok, i am confused. The 87-88 do not have a MAF unit, the 89 and updo? Why is one set up better then the other?

Ninety5five0

The others are speed density, they calculate instead of read i believe. MAF is better, you have more options with it.

vristang

It isn't that MAF is better than SD (speed density).
The major difference is that MAF equipped cars directly measure the air that is entering the motor.
An SD car calculates the air entering an engine using Manifold pressure and temperature.

If you put a camshaft in a MAF car the air flow potential of the motor will change dramatically.
A MAF car can directly measure the airflow, so the negative impact of the modification will be minimal.
The SD car relies on the accuracy of its calculations. The cam will introduce a percentage of error that the computer will not be able to account for, without a custom tune.

There are several applications where SD is still used in race/performance applications. It has its place, but it is overlly sensitive to change.
It is this sensitivity to change that motivates many Mustang owners to swap out the SD system for MAF.

FordMustangXBA

I think you mean MAP, which stands for mass air pressure, or in other words, speed density.

AdderMk2

Correction... Manifold Absolute Pressure

And it is true that MAP based vehicles have difficulty with larger cams. But systems like the megasquirt can run a map/alpha-N blend. Simply put, the car will run off a pre-set table of values based on RPM and TPS voltage until the car blends the MAP readings, then switching to the map altogether.

I have MY megasquirt setup to run on Alpha-N until 1000rpms where it will then use a blend of both alpha-N and MAP until 1500rpms where it reads only from the map sensor

vristang

Following Standard Ford naming conventions of the Fox generation...

MAP stands for Manifold Air Pressure. This is the same sensor as the mass air cars use for sensing Barometric Air Pressure; the difference being the MAP is hooked to a vac source from the intake, and the BAP is not hooked to a vac source.

MAF stands for Mass Air Flow

vristang

Obviously which cam was used would have a major impact on how well the stock Ford computer could deal with the change.
I was just using that as an example.

Aftermarket SD EFI systems are completely different. The MS for example will allow you to make changes to how the computer uses the sensor info (as you mentioned).
Basically, you can re-tune the SDsystem to run properly, with any mods. It is just that SD is more sensitive to error in the fuel/air calculations, until tune changes are made.

It is possible to get a stock Ford SD computer tuned after modification, but support for the SD computers does seem fairly limited.

That is how I understand it anyway...
jason