MAP vs AFM (splitted from smallport sale topic)

[banpei]

SekiguchiUeno Wrote:

banpei Wrote:Ofcourse the MAP is very possible on a non t-vis system, but the t-vis system needs a more complex calculation thus the map system is more efficient for the tvis system. The afm system is simpler and cheaper so for a non t-vis system it would be expected to have an afm.

banpei are you sure about this? writing mistakes happens, but is hard for beginners to select whats true and whats not, when they come here and search for info

Well, this is getting a bit too offtopic this way. So I decided to split the topic.

From what I understood the equations on AFM are simpler than on MAP:

- AFM measures the air flow, thus measuring the air volume and temperature you know what airmass entered the engine
- MAP measures the manifold pressure and combined with temperature and knowing how large the intake is you crudly know what airmass entered the engine

AFM has the drawback it actually needs the air to push a flap which measures the airflow, thus slowing down the air.
MAP has the drawback you need to do more calculations and the old ECUs don't have the power to do such math, thus using lookup tables

Given the t-vis system it opens the extra butterflies when the engine needs more air, thus sucking in more air. The ecu needs to pick this up and see how much air entered the engine but since the AFM system actually needs to pick up on the increased airspeed the MAP system should be more responsive in picking up the dropped pressure.

For a non t-vis system you don't have a sudden drop in pressure, so a AFM should be sufficient enough.

Then again: I'm no engine expert and this is just knowledge I picked up by reading stuff about engines. Correct me if I'm wrong, I'm glad to learn.