[Wayne 962]

Here's a quote from my new book (on engine rebuilding):

Many people incorrectly think that a larger turbo charger will generate more boost, and horsepower. In reality, this is not necessarily true. Installation of a larger turbo charger must also accompany other important changes in the engine. The turbo charger generates compressed air, known as boost when the blower is spun up to operating speed by the exhaust. This compressed air is then fed back into the engine’s intake system. The entire system is regulated by a pressure relief valve called the wastegate. The wastegate acts to release excess pressure so that the engine doesn’t suffer from too much boost being applied. Installing a larger turbo charger without making adjustments to the wastegate will result in no increase in boost levels.

-Wayne