yes you can run a turbo without a intercooler. You can do it with superchargers also. It depends on how effiecient the compressor is and how much it is compressing the air. When air is compressed it gets very hot. The intercooler is used as a heat exchanger just like the radiator and helps to cool down the air that the turbo added due to compression. Cooler air means you are able to tune your car more aggressively, ie leaner a/f mixture and more advanced timing to make more power. Without an intercooler i wouldn't push more then 5 pounds of boost on a turbo and even then i would retard timing a little to make sure fuel does not pre-ignite. So if you have a boost control turn down the boost to very low, and retard the timing, and adjust the a/f mixture if need be.