[rfng]

5 psi on a 3.2 requires probably 17-20 lbs of air per hour without an intercooler. You need to get the compressor map to determine which compressor you want to use. You should shoot for at least 70% efficiency for the compressor. At 10 psi with an intercooler you'll need around 30-34 lbs of air per hour.

Then you have to figure out what rpm you want it to start spooling up and select your a/r (controls inlet pressure to turbine), then how much top end power you want or need is done with the turbine trim-however as the trim get bigger you will lose some bottom end.

But whatever choice you make it will always be a compromise. Lots of bottom end, there will be no top end power, lots of top end, no bottom end. But its all relative, how much does it take to thrill yourself.

However, boost is like a drug, it may seem fast for the 1st couple of months, but with all the money your gonna be spending you want at least 7-10 psi at the minimum to give you that violent rush, its take a minimum of 9 or a rise of 3 points of compression to really feel the difference/rush. I think you'll be disappointed with only 5 psi, quick but not violent which everyone expects from a turbo.

You see every 3 psi is suppose to be the equivalent of 1 point of compression, dynamically of course. However it will yeild slightly more horsepower than its normally aspirated counterpart, as the increase in manifold pressure increases the engine efficiency(essentially allowing more air and fuel to packed into the cylinder). More fuel and air in the equivalent space=bigger explosion creating more energy being applied against the piston forcing it to move faster.

So 5 psi will only yield the approximate equivalent of 10.6-10.7 to 1 compression. The greatest yield you get with 5 psi is the increase in torque which is also horsepower, but you wont get the rush that a stock 930 gets because your not raising the dynamic compression enough.

A Stock 930 under dynamic compression jumps the effective rate from 6.5/7.0 up to 10.5-11.0 to 1 compression (a 4 point rise) or for those whose have move it up to 15 psi your increasing the compression by 5 points. That why everyone who put in the 1 bar spring say the car really comes alive.

Plan on going at least 9 psi which with give you an increase of 3 points dynamically, which is the minimum for a violent ride. 16 psi about the maximum you'll be able to run with your stock compression on the street. However as stated this will require extensive modification to your fuel and ignition system to get it to run with any longetivity. But the jump from 7 to 9 will only cost you about 2K more at a retail level as your fueling system and ignition system will only require marginal tinkering.

Hope this helps.