Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: 20thanniver-ls on November 24, 2008, 06:33:54 PM

Title: Mass air flow...Dumb question
Post by: 20thanniver-ls on November 24, 2008, 06:33:54 PM
ok heres the dumb question....  Exactly what is a mass air flow conversion and what does it consist of as far as parts? How does it help the motor? I know on my old 94 cougar it had a mass air flow sensor, but nver really understood what it was or why it was there. Could someone help me out?  :makefun:
Title: Mass air flow...Dumb question
Post by: vinnietbird on November 24, 2008, 06:39:37 PM
For the swap,you'll need the Mass Air meter and sensor,conversion harness (best is on Ebay for about $30.00....worth it),air intake ducting,and a computer for Mass Air.When you swap cams and heads,the Mass Air is good to have,if you are just doing a basic H.O upgrade,you can run Speed Density just fine (with the H.O computer for speed density).
Title: Mass air flow...Dumb question
Post by: 20thanniver-ls on November 24, 2008, 06:45:30 PM
Well im not really looking to do it right now i was just wondering what it was and what good it did thanks for the info though i was really dumbfounded on the whole subject...
Title: Mass air flow...Dumb question
Post by: vinnietbird on November 24, 2008, 06:47:44 PM
I added an E303 cam,and at that point,I knew I was going to need the Mass Air.
Title: Mass air flow...Dumb question
Post by: 20thanniver-ls on November 24, 2008, 06:49:46 PM
Why would you need it? What does it do?
Title: Mass air flow...Dumb question
Post by: Cougar5.0 on November 24, 2008, 07:28:32 PM
The mass airflow sensor (MAF) measures the mass of air entering the engine. The old speed density setups estimated the amount of aircharge based on throttle position & MAP (manifold absolute pressure) sensor & a couple of other inputs. Since the MAF measures the actual airflow, the engine can adjust to modifications fairly easily. With the speed density setup, there was a lookup table in the ECU - once you modify the engine beyond a certain amount, the lookups are way off. Since a big cam messes up the expected manifold pressure (low vacuum), it can really screw up a speed density setup. Small cams with decent vacuum are supposed to work OK with speed density.
Title: Mass air flow...Dumb question
Post by: thunderjet302 on November 24, 2008, 07:41:28 PM
Oh and don't switch to MAF unless you do the HO conversion ;)
Title: Mass air flow...Dumb question
Post by: Kitz Kat on November 24, 2008, 07:47:05 PM
Quote from: Cougar5.0;244603
The mass airflow sensor (MAF) measures the mass of air entering the engine. The old speed density setups estimated the amount of aircharge based on throttle position & MAP (manifold absolute pressure) sensor & a couple of other inputs. Since the MAF measures the actual airflow, the engine can adjust to modifications fairly easily. With the speed density setup, there was a lookup table in the ECU - once you modify the engine beyond a certain amount, the lookups are way off. Since a big cam messes up the expected manifold pressure (low vacuum), it can really screw up a speed density setup. Small cams with low vacuum are supposed to work OK with speed density.

That is a great answer!! and the truth.