This seems like a inexpensive upgrade.

How much will it help a stock truck?

If preasure increases, does that mean there is an increase in air volume and also needs an increase in fuel volume to gain HP?

Can an increase in boost without an increase in fuel hurt my truck, maybe lean it out?

Anyone know what the thread size and the nipple size is?

 

A boost elbow without a box or programmer etc will actually hurt performance.
It works like this- The ECM (engine control module) sees the boost and expects a maximum of 21 psi. So if it sees more boost it assumes that your wastegate is defective and it will reduce fueling. => less power.
You could buy a boost fooler and do the boost elbow, but this would also not net any power. (Same fueling as stock)

You can't lean out a diesel. (Since your right foot regulates the amount of fuel and it takes all the air it can get the mixture is very variable.)

HTH

AlpineRAM

 

You might search about how to make a 5 volt jumper wire to put on the MAP "manifold absolute pressure" sensor. A jumper will allow you to fool the ECM into thinking there is exactly 20 psi boost and give it full fueling capabilities and that combined with a boost elbow to mechanically allow your turbo to push more boost might net you 5 or 10 more HP. Not enough to be worth it in my mind. You need more fuel to build more boost so even with the ecm fooled, stock fueling won't build more than 22-24 psi I would imagine.