What is the difference between speed density and maf

It can be said that the MAF equipped cars are a little more forgiving to new modifications Since the MAF sensor measures air mass directly it can be said that a MAF equipped car might stay in calibration as the engine wears or in extreme environment changes however this is not normally a concern for well tuned speed density applications.

Disadvantages Sensitive to changes to the intake plumbing Can be fouled by becoming dirty. Once fouled MAF calibration is skewed Sensitive to cam reversion on large cammed cars. Limits on performance. Most systems can not read at higher horsepower levels. Speed Density Speed density systems calculate the density of the air first by measuring the temperature of the inlet air and manifold pressure.

Advantages Less restriction in the intake tract More freedom in the intake tract Able to measure air consumption on very high horsepower builds where a MAF sensor might be limited. Able to read boost if equipped with a greater than 1 Bar map sensor Free from errors encountered in MAF fouling. Works better with large cams where reversion affects reliability.

Disadvantages Is a little more difficult to tune Relies on a well tuned Volumetric Efficiency Table Less forgiving to new modifications to the engine Might have errors in large weather changes however a proper tune makes this minimal if any error.

Facebook Instagram Youtube. Speed density offers an advantage in that it is better at handling high-revving engines than a MAF sensor is. Most engines — especially those of smaller displacement — that rev above 8 or RPM are better suited to speed density.

Conversely, MAF systems deal with rapidly changing environmental or engine conditions more effectively than a speed density setup. Speed density is still preferred by many modified car enthusiasts, because tuning is simplified and because the wire within a MAF sensor can become an obstruction at very high power-levels.

Jan 22, This helps compensate for wear and tear and production variables. Other sensors on a typical Speed Density system usually include an idle-air control motor to help regulate idle speed, a throttle-position sensor that transmits the percentage of throttle opening, a coolant-temperature sensor, and a knock sensor as a final fail-safe that hears detonation so the computer can retard timing as needed.

All ''87 and '88 non-California Ford 5. Most Mopar fuel- injection systems have used Speed Density too. Because a Speed Density system still has no sensors that directly measure engine airflow, all the fuel mapping points must be preprogrammed, so any significant change to the engine that alters its VE requires reprogramming the computer.

Mass Flow By contrast, Mass Air Flow MAF systems use a sensor mounted in front of the throttle body that directly measures the amount of air inducted into the engine. The most common type of mass-flow sensor is the hot wire design: Air flows past a heated wire that's part of a circuit that measures electrical current. Current flowing through the wire heats it to a temperature that is always held above the inlet air temperature by a fixed amount. Air flowing across the wire draws away some of the heat, so an increase in current flow is required to maintain its fixed temperature.

The amount of current needed to heat the wire is proportional to the mass of air flowing across the wire. The mass-air meter also includes a temperature sensor that provides a correction for intake air temperature so the output signal is not affected by it. The MAF sensor's circuitry converts the current reading into a voltage signal for the computer, which in turn equates the voltage value to mass flow. Ford has used MAF metering on '88 California 5.

MAF systems are much more flexible in their ability to compensate for engine changes since they actually measure airflow instead of computing it based on preprogrammed assumptions. The first is the older of the two systems: speed density. Speed density systems do their work first by measuring the temperature of the inlet air and then the manifold pressure via a manifold air pressure sensor, or MAP sensor.

They then calculate a density of air with which the ECU can calculate how much fuel it needs. The ECU has to refer to a volumetric efficiency table within its programming to decide how much air the engine will be drawing in at any given speed, but at that point the calculations are made and the desired amount of fuel is squirted in. Where the MAF sensor differs and simplifies the process is that it does the work of several sensors by quantifying the actual mass of air flowing through the intake.

It sits smack-bang in the middle of the intake air flow, away from bends in the plumbing and centrally in the pipe so that it the core air flow has to pass it — ensuring the most accurate measurement. Most use an electrically-heated wire that is cooled by the passing air. The extra voltage that the car has to send to the wire to keep it a constant temperature is directly proportional to the air flow.