mass v map efi

[chpr1972]

mass sensor or map sensor. which is better? is mass better on fuel milage? Who is making mass type fi besides mass flo? Is mass easy to calibrate as map? Mass flo says that gas milage will increase up to 28 percent over carb.

[mitch_04]

My opinion? Mass air flow is going to be the best option. It is measuring the actual amount of airflow entering the engine, whereas the MAP measures manifold pressure and calculates airflow. I don't know if there is a new car out there that doesn't use a MAF sensor.

That being said, if you were going to go boosted I think MAP may be easier. It seems that boosting can max out some MAF sensors.

This is going off of a few fuel injection books I've read, not experience (although I work on both systems everyday, repair-wise). Greg Banish has 2 great books on fuel injection, although the advanced book seemed to be more basic than the other book...odd. Matt Cramer (Megasquirt) also wrote a book that is much better along the lines of building your own, however Banish (an actual autmotive engineer who designs systems) has a little more information on the actual theory behind systems. Both go into TPS, MAF, and MAP systems in their books, telling when each is benefitial.

[andrewb70]

Modern OEM EFI systems use both. Most aftermarket EFI system use MAP for the sake of simplicity. Which one is better depends on the what you mean by "better."

Andrew

[sccacuda]

I think asking that question in the '80's or 90's would be a definitive nod to MAF. With the increase in processor speeds and 02 technology, speed density systems can do everything as well as a MAF system. Think of it this way. Most OEM's using fast processors and sophisticated code use speed density in this era where every tenth off a mile matters for CAFE requirements, while the OEM's using less sophisticated processors and code still rely on MAF. If their was an advantage, all the OEM's would be MAF instead of relying on speed density and using active shutter grilles, airbag systems to lower vehicles at speed and all the other "tricks" to bump up the fuel economy.

[mitch_04]

I know one large reason that many cars still have both a MAP and MAF is because if one fails it doesn't leave you stranded. IIRC, they made the mistake of running MAF only on the early 3.8 engines, and that was where GM "learned" it wasn't the best idea. A lot of the time they are also using the MAP to measure barometric pressure as well as manifold pressure. The speed of computers has definitely went up and that does make the MAP a great option. I don't think, generally, you can go wrong with either or.