Twin Screw vs. Roots Because of their ability to produce an abundance of boost (HP and torque) at virtually any engine rpm, the Twin Screw and Roots type are the two most logical choices for
Scour the bay & CL there are there at good prices.......That’s a good explanation of the difference.
Roots are just engrained because we used to be able to go get a worn roots blower from any diesel junkyard for a half days labor. Rebuild it with upgraded bearings and a couple custom plates and BLAMO! A blower has now become a supercharger. So tons of guys everywhere could diy big power affordably (kind of).
Twin screws are purpose built and didn’t come along till long after. Never seen a twin screw in a junkyard. More power but more money.
The last decade has seen a change in the production cost lowering on twin screws and no more dirt cheap supply of junkyard blowers. When they are there, the price is high.
If buying new- definitely twin screw if you can afford it.
The 6.5 supercharger- Roots design. Why? Cost. You could have a twin screw built for it, but would be cheaper to bolt in L5P.