ok i have hptuners. im a little confused with everyone talkin about how "the computer needs to learn a tune," and "after about 500 miles u will notice your tune gets better." cause when i change things with my pcm. they are instant. it doesnt take a few days of driving around for me to notice them. if i add a lot of line pressure it changes right then and gets more firm. same with timing exc. same with tuning a truck on a dyno. a dyno tuner can get 20-30 hp out of a pcm with in an hour on the dyno and the gains are instant.


so am i missing sumthing here? is there a difference in changing the pcm compared to rewriting it. either way they can be competley new to the truck.

explain please

 

any one?

 

You're not missing anything. The only things that really learn are fuel trims and idle trims, and if you get all the tables right they shouldn't need to learn anyway.