DSMLink Air Flow Value

[SeeYaAWD]

I should mention that we are tuning a 1g with a GM MAF (and translator)

As I understand it, the MAF only supplies valid flow data to the ECU through 2400Hz. Where does the ECU get it's air flow measurement from after the MAF passes this threshold? We have a wideband installed that is reading WAY rich and a DSMLink value that is reading WAY lean. Trying to narrow down why this might be...

 

[GVR4592]

The maf needs to be calibrated using the airflow adjustments. A map sensor is usually required for this procedure. The goal is to make BoostEst and the map sensor agree at peak VE, there is a more detailed description on the Dsmlink forums

 

[olmytsi]

As I understand it, the MAF only supplies valid flow data to the ECU through 2400Hz.

Really?

 

[SeeYaAWD]

Forgive my ignorance, but by this I am assuming that the ECU would be reading air flow exclusively from the MAP sensor (never looking at the MAF?), or does it "switch over" (like in the DSMLink dialogs for the MAF) from the MAF to the MAP after 2400Hz?

 

[GVR4592]

No, in this case the sensor is for datalogging and calibration purposes only. The gm maf will read much higher than 2400 hz, that is close to the limit of the 2g maf.

 

[SeeYaAWD]

In DSMLink, there is no configuration for a GM MAF, only a 1G MAF (which has a ceiling of 2400 Hz). Will this affect the reading that actually goes to the ECU? I would assume it would be getting the air flow reading from somewhere else after it passed the specified ceiling, or there would be no point in defining one.

Thanks for the info by the way. I realize that DSMLink's forums are probably more appropriate for this type of question, but I do not have DSMLink or an account there, so I am trying to get this basic operational question answered. Basic.... to anyone who knows DSMLink that is... Thanks again.

 

[GVR4592]

No it doesn't affect the value that dsmlink sees. If you clamp the MAF at 2400hz then the ecu looks to the VE table and MAP sensor data to determine the correct amout of fuel. But you most likely don't need to clamp the MAF, you just need to calibrate it to BoostEst, using the airflow sliders.

 

[GVR4592]

Here's the how-to from the Dsmlink forums: http://www.dsmlink.com/forums/showthread.php?p=44205#post44205

 

[SeeYaAWD]

Don't suppose that thread (or explanation) is short enough to post in here. I do not have a DSMLink account and apparently the administrator has disabled new registrations...

Thanks a lot for the info!

 

[GVR4592]

How did you get Dsmlink without having access to the forums?

 

[Kevin Jewer]

Hopefully it's not a bootleg, that would be very offensive to me.

I prefer to calibrate the MAFT with WBO2, in my experience it has been much much more reliable than boostest. The problem with boostest is knowing when it is really accurate. With different setups the rpm that it is accurate at changes. WBO2 is always WBO2, and the AFratio calulation in DSMlink is very good (it's just simple math).

 

[SeeYaAWD]

No, it is not a bootleg. The guy who's car we are tuning owns it. I saw the CD yesterday and know for sure that it is not a bootleg copy. HE has access to the forums, but that does not help me out much when I am at home, so I have to rely on Tuners for info

 

[GVR4592]

You should ask him for his password or have him send you the information from the site.

 

[SeeYaAWD]

He is a member of this forum too, I will just send him this thread. Thanks for all your help! I talked to him tonight though and it looks like he has things working again (as far as the engine running anyway, the tranny might be a different story)... he changed his plugs out (from 8s to 7s) and took of his wideband and things seem to be working now... Go figure.