i dont know if this is the right place to post this. but my buddy has a 2006 lbz. it has 4 inch duals straight pipe and a ppe hot+2 that he runs level 5. sometimes when you start the truck the viens open more then close then goes back to normal. why does it do that and how come some trucks with tunes do it more than others? sometimes his does it when you come to a red light. i mean what conditions have to happen to make the veins open and close?

The veins in the turbo open and close or something like that each time the truck is cranked. If you get on the go pedal too soon it will do it the first time you stop long enough, like at a stopsign or stoplight. My truck does'nt do it any more with a tune than it did stock. Only once each time its cranked.

It does it every time to calibrate itself.

I love that sound