Discussion
Quite right, there isn't an airflow meter. There is, however a MAP sensor (manifold absolute pressure, the modern alternative to an airflow meter), but this is only used to make a correction for changes in barometric pressure (while on your Alpine holidays
).
Measuring airflow, or MAP is a way of reading the engine's load against it's RPM (and other parameters) for correct fuel metering. This is all well and good, but there is a small time delay between a change in the engine's load, and the airflow meter or MAP sensor being able to read it. Airflow meters also cause a restriction to the total inlet airflow, which reduces hp, (although MAP sensors don't).
The throttle pots can also read the engine's load, but instead by measuring how far open the throttles are (known as throttle angle), the difference is that there's no time delay for the reading.
As a result, this set-up (throttle angle) gives excellent throttle response, and is favoured from a competition/race engine point of view. Fuel consumption is not considered to be affected, but who knows?
). Measuring airflow, or MAP is a way of reading the engine's load against it's RPM (and other parameters) for correct fuel metering. This is all well and good, but there is a small time delay between a change in the engine's load, and the airflow meter or MAP sensor being able to read it. Airflow meters also cause a restriction to the total inlet airflow, which reduces hp, (although MAP sensors don't).
The throttle pots can also read the engine's load, but instead by measuring how far open the throttles are (known as throttle angle), the difference is that there's no time delay for the reading.
As a result, this set-up (throttle angle) gives excellent throttle response, and is favoured from a competition/race engine point of view. Fuel consumption is not considered to be affected, but who knows?
Hi Russel, Hi Julian.
you don't actually need to measure airflow to know how much fuel to inject - for any given throttle angle and engine revs the airflow will be the same, all you do is map the fuelling off the gas analyser / lambda sensor mixture reader without knowing the airflow.
Fuel consumption theoretically shouldn't be affected since at part throttle the mixture is lambda sensor/ecu trimmed anyway, the only downside on the cerbie is that such amphasis is placed on throttle position that and pot voltage fluctuation activates the accel enrichment.
you don't actually need to measure airflow to know how much fuel to inject - for any given throttle angle and engine revs the airflow will be the same, all you do is map the fuelling off the gas analyser / lambda sensor mixture reader without knowing the airflow.
Fuel consumption theoretically shouldn't be affected since at part throttle the mixture is lambda sensor/ecu trimmed anyway, the only downside on the cerbie is that such amphasis is placed on throttle position that and pot voltage fluctuation activates the accel enrichment.
Hmmm I have a boatload of voltage fluctuation from my right hand throttle pot. Although when the engine stationary not a jot from idle to above 4000.
No obvious play in the linkage, I guess that means I should be looking at the routing of the two wires.
However not much space to route them away from an EMF rich engine.
Has anyone tried changing the wire type to a more insulated version, is this all really worth doing or are we being too theoretical here?
No obvious play in the linkage, I guess that means I should be looking at the routing of the two wires.
However not much space to route them away from an EMF rich engine.
Has anyone tried changing the wire type to a more insulated version, is this all really worth doing or are we being too theoretical here?
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