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Thread: Fuel Table issues for MAP?

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2014-07-10 12:50:19
Fuel Table issues for MAP?
I am planning on converting to Speed Density but my fuel map lines cross on the 2D graph as the tune sits now. As the engine approaches redline the MAF load starts to come back down and the fuel numbers have to decrease, but the fuel values at slightly lower MAF load values need to be higher at the same RPM. Is this going to be a problem with the MAP or will the load values respond differently to the MAP sensor? I plan on getting the sensors and just logging the values to develop the tune before I switch, this is in preparation of a new intake manifold and i don't want to run a MAF.
2014-07-10 15:50:12
A general rule of thumb for a speed density car is that your fuel table will "follow" your torque curve to a certain point.

Since your load values will stay much more stable with the map sensor at wide open throttle, you will see that your load values will not start moving AS MUCH to the left as you get higher in RPM and your torque starts dropping off. So since your load value will stay higher, you will decrease your fuel table values to follow your torque curve.

Take a look at some of the speed density tune files in the startup calibration folder and you will see that the table values are VASTLY different than that of a MAF tune.
2014-07-10 16:53:09
Good to know. I will get some sensors installed and start logging.

Thanks John, you are always a big help and have a great product, I cant say it enough.
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