Twin 'Charger

[mikeedmr]

That's a real clean installation. I've always been intrigued by the twin charging concept, but using a turbocharger coupled to a supercharger, so each one can work in its best power band...

There have been commercial trucks with both a supercharger and a turbo charger, so I think you're right about that setup having its merits. I saw one such truck in a junk yard and I think it had a GM big block.

 

[Pro]

It was the oh my God factor!

that's what my wife says...LOL

 

[cribbj]

At some point the Vortech will be pushing the air at about the same rate as the Roots blower is trying to pack it into the cylinders. This is crossover and the belt on the roots blower will have virtualy no drag on it any more

It would seem like the Vortech could overpower the Roots, but I don't know if that's really true or not; the Roots being a PD type of device, it's going to take whatever its given and push it out the discharge. Since it doesn't create any compression internally, it's the amount of backpressure in the engine that determines the boost pressure. So if the Roots has 1 bara at its intake, and it can pressurise the engine to 1.5 bara by itself, I would think with the addition of a centrifugal, that can pack the Roots' inlet to 2 bara, the Roots will then pack the same motor with 2.5 bara. The factor that I'm not sure about is the amount of "slippage" in the Roots, and whether this would increase for higher back pressures, even if the deltaP's are the same.

I'm really out of my field of expertise on this, but I'd think for these reasons, the belt load on the Roots is going to stay pretty constant. If anyone has data to the contrary, I'd sure be interested in seeing/hearing it.

John