Supercharger+Turbocharger on the same engine...

[mertdastan]

On an engine which is supercharged and also turbocharged; assuming thatthe turbo boosts 12 psi and the supercharger boosts 9 psi. Both systems use different intercoolers. The two intercoolers' piping merge and go into an aluminium intake plenum. Will the stronger air flow of the turbo go or penetrate into the weaker airflow of the supercharger? And cause surge for the supercharger?

Or if both systems boost the same amount of air and pressure, will they force each other and what will be the total boost?

MERT

[bimmerdream]

I know Rally Lancia's used to have a sequential SC to TC system. But I believe their's would shut the SC off (clutch) when turbo kicked in. From what I remember from physics (scratching my head hard) I say it will cause boost surge on the SC end. That's one property pressure has: if there's a hole, it will use it to escape. Unless you can block the SC end off somehow (flapper door or something in the intake), the system will be a pain.
Try looking into Mazda RX7 they use a sequential turbo system. See how they deal with shutting one of the turbos off and keeping the intake manifold pressure constant. I'm pretty sure it's not though. I think there's a drop on the dyno graph when the second turbo kicks in (makes sense)
my $.02

[J Clark]

bimmer dream is pretty much right (from my gathered knowledge on the subject).

the rx-7 is probably the most popular car with that setup, try one of their boards.

they also know their forced induction in general.