I have experience with a '92 3800 SC in a fiero with some mods. Here is what I know:
I talked with a tech rep from Eaton who designed the M62 which sits atop the series 1 3800's. He said that the smallest pulley that can be used on that unit is already there from the factory. He said that using a smaller pulley would exceed the max rated RPM of the M62 when used on the series 1 engine operating at it's factory redline resulting in catastrophic supercharger failure.
So in effect, he told me there is no way to "turn up the boost."
Again, this is not heresay, this was info straight from and Eaton Tech Rep.
With that being said, there are a few things you can do to improve the performance of the 3800 series 1 engines without touching the supercharger.
The 3800 I engine uses tubular exhaust manifolds that sport a rear dump to the cat-con. I have discovered that the opening from the exhaust manifold plenum to the dump flange is not optimal for flow and can easily be ported, even while still on the vehicle. This "opening up" of the exhaust system is worth at least a .1 sec gain and a few MPH in the 1/4 mile depending on the rest of the exhaust system.
Obviously other gains are to be had by installing a less restrictive exhaust and induction system which may include modification to the stock airbox should you choose to keep it. You cannot, however, remove the screen from the throttle body because it is required by the MAF sensor to operate properly. Increasing the fuel pressure will also help if these other mods are done helping the engine breathe a little easier. You can increase the fuel pressure by mashing in the top of the stock regulator using a small ball-peen hammer slightly. This will only work if you have the regulator that has no torx screw in the top of it and the vacuum line enters from the side. Care must be taken so you don't damage the fuel rails or "mash" the top in too much which will result in excessive fuel pressure. Compressing the top of the regulator roughly 1/16" of an inch yeilds approx a 2 lb gain in fuel pressure. Do this with a fuel pressure gauge on the fuel rail and the fuel pump running so you can see the results of your modification as you perform it. Unfortuneately, this process cannot be undone without changing to a new or untouched regulator so use caution.
