Hotwire vs Flapper
Discussion
Good question and sure it will get a few differing answers, but to explain in brief.
The older vane airflow meter has a variable resistor that measures the movement of the vane as air flows through the airflow meter. It doesn't actually measure airflow directly but the drag caused by the air as it flows through which is proportional to the airflow. It does not cater for the air density just flow and additional sensors are added to calculate adjustment for changes in air density.
Hotwire airflow sensors use a heated wire that is heated by either a constant voltage or constant current, the amount of current or voltage to maintain the wire at a set temperature provides not only the airflow but also air density. As airflows over the wire it removes heat and therefore more voltage or current is required to maintain the heat, the denser the air the less flow is required to remove heat and therefore the hotwire airflow meter caters for both airflow and air density.
Their are benefits in the later hotwire system, these include less drag and reduced airflow, less prone to mechanical failure, responds very quickly to changes in air flow, doesn't really care about the mounting location, orientation etc.. The system reduces the number of I dependant sensors required to determine airdensity, smaller and cheaper..
Other changes are less obvious, these will include updated software more capable of providing more accurate fueling which in tern provides more power with better fuel consumption and less emissions.
If you want any more info just shout..
The older vane airflow meter has a variable resistor that measures the movement of the vane as air flows through the airflow meter. It doesn't actually measure airflow directly but the drag caused by the air as it flows through which is proportional to the airflow. It does not cater for the air density just flow and additional sensors are added to calculate adjustment for changes in air density.
Hotwire airflow sensors use a heated wire that is heated by either a constant voltage or constant current, the amount of current or voltage to maintain the wire at a set temperature provides not only the airflow but also air density. As airflows over the wire it removes heat and therefore more voltage or current is required to maintain the heat, the denser the air the less flow is required to remove heat and therefore the hotwire airflow meter caters for both airflow and air density.
Their are benefits in the later hotwire system, these include less drag and reduced airflow, less prone to mechanical failure, responds very quickly to changes in air flow, doesn't really care about the mounting location, orientation etc.. The system reduces the number of I dependant sensors required to determine airdensity, smaller and cheaper..
Other changes are less obvious, these will include updated software more capable of providing more accurate fueling which in tern provides more power with better fuel consumption and less emissions.
If you want any more info just shout..
Edited by keatsie on Saturday 8th February 21:00
And more general information:
Hotwire more easy to tune = possibility to change the chip and get that reprogrammed if you want. Tornado chips are about and you just need the right chip socket to be able to change it.
Flapper difficult to tune. Can't change the chip, rest is resistors: remains the fuel pressure regulator.
Flapper needs the resistor pack to go with the injectors, on the hotwire they are different and run direct of the ECU.
Rob
Hotwire more easy to tune = possibility to change the chip and get that reprogrammed if you want. Tornado chips are about and you just need the right chip socket to be able to change it.
Flapper difficult to tune. Can't change the chip, rest is resistors: remains the fuel pressure regulator.
Flapper needs the resistor pack to go with the injectors, on the hotwire they are different and run direct of the ECU.
Rob
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