DSMlink MAS/MAF Calibration Page

WOT Airflow Calibration

Fuel Trim Calibration Page - Click Here

After posting many threads on the DSMlink Forums website regarding how to calibrate a 1G MAF, 2G MAF, EVO MAF or GMAF Translator, I decided to create a Write-Up on my site. This way I can direct users with problems right here.

This is what you do. (Make sure you have MAFraw captured)

1) Go to (F4) Values
2) Click BoostEst
3) Click "Props"
4) Enter correct elevation and displacement
5) Datalog a 3rd gear pull from 2000 to redline

A boost sensor like a AEM5Bar is not required, but it does make things easier to calibrate. If you don't have a map sensor (like me), then just pay attention to the boost gauge so you know what actual boost was during the pull. Then examine the BoostEst curve in between 5000-5500 RPM. This is where VE is 100% and where you want actual boost and BoostEst to equal each other as close as possible. If you have aftermarket cams, sheet metal intake manifold and a high flowing head, then you can stretch the RPM range to 5000-6000 RPM.

In this case, let's just concentrate on 5000-5500. Look at MAFraw in between 5000-5500 RPM so that you know which airflow sliders you are going to have to change. Here is the equation you will need to use to know how much you will need to move the sliders.

((Actual Boost + 14.7 PSI) / (BoostEst + 14.7 PSI)) - 1.0

For instance, at 5500 RPM...

BoostEst = 10 PSI
Actual Boost = 15 PSI

((15+14.7)/(10+14.7)) - 1

(29.7/24.7) - 1 = +.202

This means that you need to take the airflow slider(s) up 20%. You need to datalog MAFraw to know which airflow slider to adjust. If you are only at 1200Hz between 5000-5500 RPM, then this equation would pertain to the 1200Hz slider.

Once you get 5000-5500 RPM lined up well, I would just interpolate the other sliders and blend them in. It should work decently fine just be doing that.

Another example. This time an actual log from a DSMlink user that I located on the forum.

Notice on the DSMlink Screen capture above, the user is at these values...

RPM = 5682

Actual Boost = 21.7 PSI

BoostEst = 34.3 PSI

MAFraw = 2841 Hz

We've got a ton of calibrating to do. This particular log shows a good amount of boost being pushed through the motor. What I like about this log is that boost is very stable, so you can almost see the VE curve in the BoostEst curve. Notice how BoostEst peaks and then falls as the motor gets closer and closer to redline.

The airflow slider we are most concerned about is the 2400+Hz slider, because at 5500 we are already way past 2400Hz. Now it is time to plug the values in the equation.

((21.7 + 14.7) / (34.2 + 14.7)) - 1 = -25.5%

According to the calculation, we need to bring down the 2400Hz slider down 25% from where it is currently at. A drastic compensation like this usually will be caused by a boost leak after the GMAF.

NOTE : If for some reason you need to pull more than the DSMlink allowed 20% away from the 2400Hz slider, you may need to use the WOT Translator knob and take addition airflow away.

Now what about the other airflow sliders like 1200, 1600 and 2000Hz? You can take the easy way out and just gradually blend them in with the 2400Hz slider. Or you can do it the long and more accurate way.

The way to do this is to lower down the boost until MAFraw drops low enough that you are at 2000Hz while you pass through 5000-5500 under WOT conditions. Use the airflow equation for the 2000Hz slider. Then lower the boost again until MAFraw is 1600Hz as you pass through 5000-5500 under WOT conditions. Repeat again for the 1200Hz slider.

NOTE : GMAF calibration and Intake Air Temperature : The GMAF assumes the intake temps are in the 79-81F range. Any difference from this temp and there will be a change in BoostEst.

For every +10F degree change in intake temps, BoostEst will drop approximately 1.0 PSI. (Info taken from Rick E. Martin posts in DSMlink forum)