Question for Chevy dually guys.

[Ron Finney]

Tony,

You can make some minor mods such as better exhaust, K&N filter, etc. However, your truck is a speed density system which means it does not measure the airflow, it is calculated based on cu.in x rpm and then factored for load, air temp and barometer. The newer stuff has mass airflow so it is physically measuring the air coming in and can adapt for increases in airflow. What this means is that on a speed density system if you modify it too much, the calibration can't adjust because it is still assuming a pre-programmed amount of airflow. Example, early mustang GT's guys put the offroad H-pipe on them doing away with the cats and the cars would have idle issues, surging, dying etc. they ran good at WOT because it goes into open loop and max fuel delivery. In your case you need to maintain driveability.

Hope this helps. See you at the track!

Ron & Meridee
396V S/C