A bit of background I have done a number of Speed density (non-GM) systems so reasonably good at tuning. This is my first MAF system and first GM PCM so have a few newbie questions. The pcm came out off of a 5.3 and is going on a 6.0 with LS6 stock injectors - I have the stock injector table in the tune now. First start is in a few days.

I know the fuel table is going to be off and no issues going to tune it ( I hope so anyway).

I installed a 4" dia air tube and filter (I had them on the shelf).

Questions are:

1) which way does the MAF table need to change?

2) can an initial assumption be made by the ratio of the OEM tube area vs the 4" tube area?

3) what to adjust first the MAF table or the actual fuel table?


for example if 1000Hz = 30 grams air <<< stock

Does the 30 grams now become 45 ? Or 20 grams ?