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View Full Version : quick theoretical question on AEM EMS scaling


i3igpete
08-06-2013, 01:42 PM
So, suppose I switch from a 3.5 bar to a 5 bar MAP sensor. Now, I know when you pick the sensor type in AEMPro, it rescales the load axis. But suppose I change the load scalar so that the load points are (nearly) the same. Theoretically, would I need to change anything in my fuel/ignition tables?

Is there any real difference? I assume the only thing I would really need to "tune" for is if the sensor voltages are not calibrated perfectly, right?
Greg E
08-06-2013, 04:58 PM
Correct.

13psi is still 13psi be it at 2.7 volts or 3.2 volts.
Ninja Performance
08-07-2013, 10:42 PM
The problem lies in the tables, where you used to have (example) a graduated load axis of -14 vac to 32psi , now you have -14 vac to 50psi. And what used to be your 13psi load line is no longer your 13psi load line, this applies to any table with a load axis. Could be after installing the 5 bar, what used to be the timing and fuel for 13psi is now on the -2 line.

So you can't just pop in the sensor, tell AEM Map sensor wizard 5 bar and be set. Your tables need to be all readjusted. Save old cal, make change, open offline the old cal and use it to figure out where each load point line was and adjust accordingly.

-Chris
J. Fast
08-08-2013, 02:11 PM
The problem lies in the tables, where you used to have (example) a graduated load axle of -14 vac to 32psi , now you have -14 vac to 50psi. And what used to be your 13psi load line is no longer your 13psi load line, this applies to any table with a load axis. Could be after installing the 5 bar, what used to be the timing and fuel for 13psi is now on the -2 line.

NSo you can't just pop in the sensor, tell AEM Map sensor wizard 5 bar and be set. Your tables need to be all readjusted. Save old cal, make change, open offline the old cal and use it to figure out where each load point line was and adjust accordingly.

-Chris
^This! You have to manually transfer fuel and timing for equivalent kpa vs rpm ranges. In V2 and Infinity series EMS the auto re-scale feature will do it for you and flatten non transferring cells.