What do I have for a Mass Air Meter?

[vristang]

I finally contacted someone on the Ford Tech line.

The 93 Cobra 70mm MAS sensor is not interchangeable with the 5.0HO 55mm MAS sensor. The way I understand it is that the output voltages are not on the same scales. So...

At idle both MAS sensors could be at say .5v and ~30 kg/hr of mass air flow.
At higher rpms both sensors could be reading the same as well, say 4.5v and 1000kg/hr.

This would be due to both sensors operating on the same 0-5v range. Both motors have similar airflow capacity, so similar amounts of air would be flowin at min and max levels.

However, the rate at which the voltage changes with respect to mass air flow can vary in the middle of the 0-5v range.

At 1/2 throttle the Cobra meter could read 2.5v and ~200kg/hr.
While the A9L 55mm sensor could read 2.5v and ~180kg/hr.

I made these numbers up, but they illustrate how the rates can vary between the two sensors, even though they both have the same range.
If the MAF curves were linear we wouldn't have this trouble.

Long story short...
If you have an A9L, you must use the 55mm MAS sensor.
If you have an X3Z, you must use the 70mm MAS sensor.
The MAS must be matched to the ECU.
We cannot mix and match.

I will be adding this to the FAQ section on my website.

Hope it answers your guys' questions,
jason

 

[GT_Rich]

?

Thanks for taking the time to sort that out. There's one thing I'm still not sure of:

I have an A9L computer and i'm using the 55mm MAS, but it's on a 70mm housing. The way I read your post, that is okay b/c I've matched the MAS with the computer. What about housing size? How can it not matter?

 

[vristang]

Thanks for taking the time to sort that out. There's one thing I'm still not sure of:

I have an A9L computer and i'm using the 55mm MAS, but it's on a 70mm housing. The way I read your post, that is okay b/c I've matched the MAS with the computer. What about housing size? How can it not matter?

Guess I need to re-write that.

You will want to either use a stock 55mm housing. The MAF transfer will be all over the place if using an A9L/55mm MAS/70mm MAF/19lb Injector combo. Also the MAF/MAS is not matched to the Injector size, as needs to be done when NOT using a tuner.

Rich,
I would pick up an aftermarket MAF housing from C&L or Pro-M. Make sure it is appropriate for your setup.

I'll revise my FAQ sometime today. The current version on my site has a chart of 2 different maf transfers that should help exlain things.

jason