Could you boost an N/A like 3 psi with a supercharger, like off of a thunderbird (geared down for low boost and high redline), and trick the atmospheric pressure sensor into thinking you are at an area with 3 psi boost more than normal (like going from my altitude to sea level)?
Would that work, or would the fuel system be insufficient?
Just a thought.

 

No need to to trick the pressure sensor. The car will add more fuel accordingly since there is more mass of air going through the AFM.
Anyways, 3psi??? What's the point?
The fuel system will be suffectient- since you won't be putting out any more power!!!!
With a turbo, you need to run about 3-4 psi before you gain any power over running a free-flow intake and exhaust, this is because the turbo represents a huge intake and exhaust restriction, and needs to compensate for that initaialy.
As for a supercharger, it represents the same intake restriction, and also applies parasitic drag to the engine, entirely eliminating any gains from 3psi.
You'd need to run about 5 psi to get and noticable HP gains, and then you would need to start upgrading the fuel system (a TII pump and 4 injectors are cheap and readily available)

 

Well just so you know the MAP sensor reads upto 4psi. Wether or not the computer will change the timing upto that far im not sure.
I can also say that the STOCK N/A fuel system is fine for 5psi with a stock S4 turbo.

 

Bambam7, when the bearings in my turbo were shot and it was only making 1psi (2psi at redline) it was still a **** load quicker than my car was when it was N/A.

 

A supercharger running 3 psi boost will obviously be easier to turn than one running 10 psi.
It's all percentages. 3 psi is about 20% of normal pressure, so you could get about a 12-15% hp improvement out of it.