With the stock turbo it can only do 15psi of boost. Any more and its just shooting heat into your engine. Aftermarket I would't go anywhere above 40lbs/min.
You can put a supercharger on a stock engine it depends on how much boost you run wether your engine can handle it or not.
Eagle Talon and Mitsubishi Eclipse turbo models run 7lbs of boost as a factory setting.
The f22b1 is a great engine for boost it has a compression of 8.8:1 and can handle 12.1:1 so you boost about 11-12lbs. On the stock internals no problem.
you might be running too much boost off of your turbo especially if youre running a stock turbo
140 hp stock 420A engine
I believe it is in the ball park of 14 to 15 psi of boost. That is what my turbo talon run. Edit: A stock 1g DSM (Talon eclipse laser) has it set at 9-12 PSI. while the stock gauge says 14 sometimes it should not be trusted. get a aftermarket boost gauge and find out yourself
Stock turbo can run close to 14 PSI...but you can increase as much as your turbo can. The engine will not last as long with higher boost. Upgrading internals such as pistons, rods, crankshaft, camshaft, and valves can allow much higher boost.
If it hasn't got a turbo there's no place for it to get boost from.
7 psi is safe to boost on a stock d-series motor
8psi
Stock is around 9psi.
about 60psi