Intercooled Vs. NonIntercooler
There has been many debates between the issue of intercooling and nonintercooling. Here are some facts based on Corky Bell's book called Supercharged!. Here is some interesting information you should considered when you plan to get a forced induction system. Before we start, here are some legends you should understand: Here are some formulas will be useful: Desired Power = stock power x pressure ratio x density
ratio x volumetric efficiencies ratio x drive power efficiency Volumetric Efficiencies = supercharger volumetric efficiencies / engine volumetric efficiencies Pressure Ratio = desired power / existing power or
Density Ratio = original absolute temperature / find
absolute temperature Centrifugal:
Lets plug in some numbers and make it real. Now we will be using our first generation 1UZFE. A car is rated at 220 bhp and our desired bhp will be 300. Lets use these formulas and see how it will affect the outcome between intercooling and nonintercooling. The below table show amount of boost require to achieve 300 bhp
What the above table saying is that for a 220 bhp to make 300 bhp. It would take a 10.1 psi in a nonintercooled root style supercharger system to make 300 bhp in the same intake/chamber temperature as a 4.7 psi intercooled Centrifugal supercharger system. In another word, it will take a 10.1 psi from a root style supercharger to make the same power as a intercooled 4.7 psi from a Centrifugal Supercharger system. Here is an database that I have complied using 250 bhp as our stock horsepower and comparing Root supercharger and Centrifugal along with intercooling. The boost require for a intercooler Centrifugal system to make 400 bhp would be around 6.6 psi vs. nonintercooled Root Style 12.52 psi. The below data is calculated using Corky Bell's book and formulas.
Full data from Excel Spread Sheet Boost Calculation and Pressure Ratio Pressure Ratio = desired power / existing power Density Ratio = original absolute temperature / find
absolute temperature
Here is what Corky have to say about intercooling: "The intercooler can rescue this bad temperature situation. Let's look at the whole picture again when we place an intercooler between the supercharger and the engine. Assume the intercooler will remove 85% of the temperature put in by the supercharger. To calculate the final intercooled chamber temperatures, we use the same procedure as in the previous section, inserting the intercooled temperature gains from in the temperature formula for a 9:1 compression ratio. This shows that with intercooling, we can run substantially higher boost before reaching the arbitrary 1075 degrees limit: about 10 psi for roots and 13 psi for centrifugal and twin screw. Although this exercise in numbers is full of approximation, its easy to show, for example, that you can run 40 psi boost intercooled at the same chamber temperature as 8 psi nonintercooled". Here is an extreme comparison between low thermal efficient and high thermal efficient supercharger. Secondly, we also compare a nonintercooled root style supercharger with intercooled centrifugal supercharger. Nonintercooled root style supercharger Vs. a intercooled centrifugal supercharger
Below are the comparison between intercooled Centrifugal and Root Style Supercharger and along with nonintercooled.
If you compare a nonintercooler root style at 10 psi vs. a intercooler centrifugal at 10 psi is 130 degrees F to 13 degrees F. Its also 100 degrees difference at 10 psi. The above data is from Supercharged! book page 40 and 42 ISBN 0837601681

