With the release of ECMLink, users have the option to run any number of different mass airflow solutions. They can run a Mitsubishi MAF sensor (1G, 2G, EVO8), any one of a number of GM MAF sensors, or they can run speed density. This page outlines some of the considerations of each.
If you're not sure how airflow plays into the grand scheme of engine management, then please read the Engine and ECU operation page first.
The “standard” options include a 1G DSM, 2G DSM, or an EVO8 (3G Eclipse) mass airflow sensor. Some things to note with these follow.
A popular option for running a non-Mitsubishi mass airflow sensor with ECMLink is to run a GM sensor instead. Some part numbers of compatible sensors can be found on our GM MAF Part Numbers page. Some things to keep in mind with these follow.
These sensors are designed to work with laminar airflow through the entire cross sectional area of the sensor.
When you run small piping up to a large sensor, you concentrate airflow into a small area of the sensor's cross section. This violates its assumption about airflow through the sensor and throws the airflow reading off.
When you install the sensor after the turbo (typically in the upper IC just before the throttle body), you're asking it to measure very turbulent (not laminar) airflow. This also violates some of its design parameters and throws the airflow reading off.
Honestly, given the typical installation of these sensors on the typical DSM, I'm surprised they work at all. But they do work and they can be made to meter pretty well even though we're pretty much breaking every rule in the book about their installation and operation constraints. I guess that says something positive about the sensor design after all.
We do provide a dial-in procedure that helps get airflow working right and, as I mentioned, they do seem to work pretty darn well once dialed in properly. When I run my car on the GM MAS, I can't tell any real difference between it and a Mitsubishi mass airflow sensor or speed density. It works fine for me and countless others. Some people, however, do have problems. Particularly with moisture issues. Even on my own setup, when my turbo started to develop a problem that allowed some oil to get into the intake side of things, the GM MAF got very upset and I knew pretty quickly something was wrong.
Speed density operation only requires three things: a manifold pressure sensor, an air temperature sensor and some idea of the volumetric efficiency of your engine. Much more details can be found on the following pages.
Since most people will already want to log manifold pressure anyway, that sensor is typically already available. And installing an air temperature sensor isn't much work at all.
So the only “tricky” part is getting your VE table dialed in. But that isn't really hard either because we provide a couple dial-in procedures that make this process quick and painless.
Some things to keep in mind follow.