The quality Aluminum Map Sensor is designed to measure the manifold�s intake pressure and use that signal as a fuel mixture control parameter. This sensor is enclosed in an aluminum holder to protect it in the engine compartment. They come in 4 versions, 1.1 Bar, 2.5 Bar, 3 Bar and 4 Bar. The accuracy of these sensor makes it possible to use the 3 Bar sensor for normal aspirated engines. It will be scaled by the software. In some cases the 4 Bar sensor is also used as a fuel pressure sensor for normal aspirated engines.
The 1.1 Bar is used for altitude compensation sensor on the Mercury 2.