Just installed AEM serial data gauge... reads more boost than AEM?

[Dasstrum]

Ok, after installing my AEM serial data gauge (which actually was surprisingly very easy) I noticed that the boost gauge on it was reading higher than the AEM.


When I do a pull with the AEM hooked up to my laptop and viewing the engine load, my max PSI is 22.5. Then when I hook up the serial gauge back up without the laptop and do a pull, it reads 26.5!

Why would there be such a big difference? I know its not actually hitting 26psi because I have fuel cut set at 25psi. Nutz, can you help me out

[nutz]

tell ya the truth i dont know much about it, but one of the base maps for that works good for my car try some others

[Dasstrum]

Well, the one I loaded was one of the Configs that came with the software for the gauge. I loaded the "BASE CAL AEM 3.5 bar" file. I do have the stage 2 MAP in the car which I think is a 3 bar, but I don't think that would matter. The only thing it does in the program I think is set the "High Alarm" to 35.3psi default instead of 15.3psi in "High Alarm" if I loaded the "BASE CAL AEM 2 bar".


As far as I know, in the program, does it matter if its set up to 3.5 bar map if I am running a 3 bar map? Boost is Boost right, that .5 more on the MAP just means it can read a higher amount of boost right?

[nutz]

i think there is a honda map that works with the 3 bar

truthfully its been a long time since i have messed with it

[chuck's_srt-4]

Quote: Originally Posted by Dasstrum

Well, the one I loaded was one of the Configs that came with the software for the gauge. I loaded the "BASE CAL AEM 3.5 bar" file. I do have the stage 2 MAP in the car which I think is a 3 bar, but I don't think that would matter. The only thing it does in the program I think is set the "High Alarm" to 35.3psi default instead of 15.3psi in "High Alarm" if I loaded the "BASE CAL AEM 2 bar".


As far as I know, in the program, does it matter if its set up to 3.5 bar map if I am running a 3 bar map? Boost is Boost right, that .5 more on the MAP just means it can read a higher amount of boost right?

Not exactly. I think that's your problem, right there! If you have the serial data guage calibrated for a 3.5 bar sensor, and the AEM calibrated for a Mopar 3 bar sensor, there is going to be an obvious discrepancy between them.

Both the Mopar 3 bar and AEM 3.5 bar sensors work off of a 0 - 5 Volt scale, and interpret the voltages as x psi/volt.

For example, here's the scale for the AEM 3.5 bar map sensor:

Volts: 0.5 -- 1.0 -- 1.5 -- 2.0 -- 2.5 -- 3.0 -- 3.5 -- 4.0 -- 4.5
PSI: -14.7; -8.45; -2.2; 4.05; 10.3; 16.55; 22.8; 29.05; 35.30

And here's the scale for the Mopar 3 bar map sensor (starting from 1.5 volts, as I don't have the full scale in front of me):

Volts: 1.5 -- 2.0 -- 2.5 -- 3.0 -- 3.5 -- 4.0 -- 4.5
PSI: -1.30; 3.00; 7.80; 12.00; 16.90; 21.00; 25.50

You need to have the AEM serial data gauge calibrated to the same sensor you're using.