RIPP vs. Magnuson...SuperCharger Shootout!

[UselessPickles]

A twincharger system (supercharger + turbo) sounds awesome in theory, but good luck implementing it well and getting all the transitions to happen smoothly for a good daily driver without more than doubling the cost of the vehicle. That kind of stuff requires good electronic control over the clutch, bypass valve, and wastegate, integrated with the rest of the engine control systems. No one makes such a kit, so it would be a totally custom system.

A sequential twin turbo setup is more realistic than twincharging, but even that would be very expensive as a one-off custom system and may suffer from some daily driving compromises with purely vacuum/spring controlled valves, etc.

It doesn't seem worthwhile to discuss theoretically optimal setups that are vastly different than what is available on the market, unless you have the money/skills necessary and plan on building and tuning a custom system.

[KaiserBill]

Not really... Useless Pickles-- the Detroit Diesel two-strokers were all supercharged for low rpm idle to 650-800 up to about 1200-1300rpm and turbocharged after 1300rpm for normal use. You cannot make a two-stroke diesel and not use a supercharger for scavenging. The system has been around for decades. You're correct it does add complexity-- but you don't need electronic controls to do it. A simple clutch either mechanical or electromechanical can be used to disengage the supercharger. The bypass valve is basically just a very large waste gate and that be operated via the clutch. And waste gate itself doesn't really have anything to do with it. You operate it with or without one. The Detroits used run about 18psi of manifold pressure and they had no waste gates on them. The used to run on the big series engines like the 16V71's two supers and four turbos. So you could get 800hp at 2100rpm and 2000ft-lbs of torque-- where the maximum would be at 1600rpm and be like 2150ft-lbs. Two Stroke Diesels are incredibly flat with their torque curves.

Sequential is good. In fact International offers Sequential turbo charging on their DT series engines as does Detroit on the smaller models but their bigger models use a Compound System.

None of it is theoretical is all practical and has been done for decades. A lot of the pioneering work for turbocharging actually started during the end of WWI.