Compound twincharging with centrifugal supercharger

[johandelivera]

I have a 2JZ engine swapped into a BMW E46. The 2JZ as everyone probably knows is a 3 liter straight 6. Mine has the stock sequential twin turbo (0.5 bar boost when turbo 1 kicks in at 2500 RPM, and total boost of 0.8 bar with both running at 4500 RPM). I recently acquired a used HKS centrifugal supercharger GTS8550 quite cheaply, pressure ratio 2.6 and max flow 26m3/min. The SC has a traction drive that is supposed to reduce parasitic loss at high RPM.

My questions:
I plan to feed the turbos into the SC to compound boost.
1) What boost can I expect to get total? I have read the threads here on twincharging using roots blowers, but was unclear if the same principle of compound boost multiple applies since this SC is not a positive displacement pump.

2) Should I install a wastegate after the SC to control total boost?

 

[Lou Scannon]

Assuming you know what you are doing, you need to get maps for each of the stages, and make a layout to calculate what will happen. Part of the exercise will be figuring out the drive ratio for the centrifugal supercharger.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[EdStainless]

And working out the intercooling, otherwise you will just put the same mass of hot air into the engine.

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