Speed density vs. Mass air
Speed density vs. Mass air
Posting Guru
Joined: Jul 2002
Posts: 2,205
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From: Vancouver WA
Speed density vs. Mass air
Mass air vehicles will have a sensor in the air tube that goes from the air filter box to the throttle body, usually close to the air filter end. If there is a sensor with wires running to it in the air tube, it's mass air. No sensor, speed density.
Posting Guru
Joined: Jul 2002
Posts: 2,205
Likes: 1
From: Vancouver WA
Speed density vs. Mass air
Speed Density systems rely on sensors that measure intake manifold vacuum (and probably a few others) to regulate fuel/air ratio. Mass Air uses a sensor in the air intake tube that actually measures the amount of air coming in to the engine. SD can get really messed up by doing lots of modifications on your engine that affect vacuum like bigger cams. Mass Air isn't affected by that because it's still measuring actual air flow.
Post Fiend
Joined: Nov 2002
Posts: 9,987
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From: Memphis, TN
Speed density vs. Mass air
Speed/density uses a preset program based on engine specs, truck weight, transmission, and several other criteria to control the engine, using the sensors only to choose which data table to use.
MAF measures all those things all the time to figure out how to run the engine, and that's why it can adapt to bigger changes.
MAF measures all those things all the time to figure out how to run the engine, and that's why it can adapt to bigger changes.
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