2QYK4U

I now have an AEM 3.5 bar MAP sensor installed in my S2000. From what several people have told me, this sensor is essentially plug 'n play with the exception that I need to go into my EMS and change the MAP sensor from stock to AEM. All the other existing tuning variables (i.e., air/fuel/timing/etc.) are supposed to be ok. Do you guys believe that to be true, or do you believe the car needs to be re-tuned with the new MAP sensor?

snakeeater

As long as you configure the scaling correctly, so that it correctly reads MAP, there is no need to retune. Unless you upgraded sensors in order to run higher boost pressure. Running higher boost will require tuning at the new elevated boost levels.

2QYK4U

Scaling profiles for the different MAP sensor are already provided in my EMS. When I selected the AEM 3.5 bar MAP sensor, it automatically inputted the scaling values.

2QYK4U

BTW...my car was tuned to almost 13psi with the stock MAP sensor. Some people believe that the stock MAP sensor can only support 10-11psi before it starts going whacko and providing false readings. If this is correct, and my car was tuned to 13psi, would you agree that my tune could be off and that the car should now be tuned to 13psi with the AEM MAP sensor?

snakeeater

That is the safest approach. It probably wouldn't take long to check the tune above 10 psi.

Are you going to try for more than 13 psi any time soon? It may make more sense financially to do both while its at the tuners.

2QYK4U

Not until I have my inlinePRO 3mm headgasket installed, which won't be anytime soon. The only reason why the car was tuned to 13psi in the first place was because we had an issue controlling boost. The tuning stopped at 7400 RPMs because the boost was continuing to rise. I now have a smaller wastegate spring, and am also having a 3" single exhaust made, so hopefully boost creep will be reduced (if not eliminated).

AusS2000

When I installed the 3.5bar MAP I used the wizard to tell the software I was upgrading.

The stock MAP is a 1.7bar MAP sensor so the AEM 3.5 has twice the range. So you'd expect all my tuned values to appear in the bottom half of the fuel table right! Nope, they were spread across the whole table. So the setting I used to have for say 10psi and 9000 revs was now in the cell for 35psi and 9000 revs. Not good.

I then had to select the entire table and copy, then select the bottom half of the map and pasted. The software interpolates the values but some retuning is necessary.

I also did some approximation for the top half of the map by doubling the top line and interpolating between it and the pasted top line (about 11psi). This was only to give a good base for tuning.

Another thing to consider is the upper limit. You only have 17 cells to play with and if you've got them spread across 35psi but only intend to go to 20 you are wasting about a 1/3 of them. You can change the values each line represents in the Load Breakpoints setting.

2QYK4U

I just confirmed with the manufacturer of my EMS that the AEM MAP sensor is indeed plug 'n play with my EMS. All I needed to do was select the appropriate MAP sensor from the list of available sensors on the "MAP" tab and all corresponding values were prepopulated for me. I was also told that the air/fuel/timing maps were unaffected by this change and should be good to go.

AusS2000

So what values did it enter in the fuel and ignition fields for values above 12 psi?

2QYK4U

I don't have an AEM EMS--I have a different EMS, and mine has 4 tables consisting of:

Table 1: 10 columns for low speed ignition
Table 2: 10 columns for high speed ignition
Table 3: 10 columns for low speed fuel
Table 4: 10 columns for high speed fuel

I don't see any reference to boost levels in these tables. The values for the x-axis are for "mBar" and the values for the y-axis are for RPMs.