MAF porting

[Eric]

Hi everybody Eric here , new to efi live but love the product the flashscan v2 is a nice piece ,using it with an LM2 in serial hookup , ok i am porting my MAF meter on my sc 2000 silverado and i will be removing the screan and puting the MAF meter further back from the filter so the air will have time to staighten out coming from the filter givin the fact that the screan is there for that , so i am wondering how will this affect the tune , correct me if i am wrong but this will in a way trick the computer into seeing less aif flow if i do not compensate in the tune because by porting the MAF meter i will be slowing down the same amount of air as before so this will increase my timing , how do i ajust for slightly larger MAF diameter or do i leave it like that and see what gives , anybody done this succesfully , thank you oh forgot to say , i want to remove that clunk of plastic down the center of the MAF unit while just leaving the sensor like the aftermarket ones , but not sure

[eficalibrator]

You are correct that the porting, relocation, and removal of the screen can all affect the behavior of the signal returned to the PCM from the MAF. Generally, porting the MAF increases the cross-sectional area and allows more total airmass to pass for the same signal from the wires. The net result is a lean shift of the open loop fueling, it's just not linear.

To fix it, you'll need to do some logging (preferably with a wideband, in open loop) to characterize the error between the new MAF's performance and what the PCM thinks was in there. You will use this data to recalibrate the MAF Hz vs. Airflow table to bring the delivered fueling back in line with commanded.

When you're all done, I doubt you'll find much benefit from the MAF porting if you run the same actual delivered AFR and spark. Of course, you could have changed that with software alone... ;)

[Eric]

thanks for the info Greg