Boost
I've tried most kinds of superchargers over the years, and have come to the conclusion that when planning a project, you must first decide on your goals. Each type of blower has its own set of characteristics.
The roots-type installation done by Quik is superb for creating, in effect, a larger displacement engine. But instead of more actual displacement, you simply, in linear fashion, cram extra air, and the concomitant fuel, into the existing cylinders. Instant torque, and, as I said, linear. The drawback is that it takes a lot of power to run one, and the efficiency drops off rapidly at higher RPM. It's been estimated that the GMC-type supercharger on a 'AA Fuel' dragster engine takes upwards of 1000 horsepower to run.
Centrifugal blowers are much more efficient, but they have their own problems. First, for our purposes, is the packaging difficulty. There simply isn't room around the front of our engines for the placement of a device that's at least a little bit bigger than your head. In terms of function, there is little low speed augmentation. They are more efficient than a roots-type.
Now let's look at turbochargers. First, because they are run by harnessing exhaust gasses, it's possible to locate them anywhere in the exhaust system. Although, theoretically, some locations are better than others, the possible problems are readily solved by the proper sizing of turbine and compressor sections, all readily available.
And, because they function 'on demand', meaning that in steady-state driving they are idling---not providing boost---your engine is operating much as a stock engine would. The turbo's not noticeable. But with the extra rush of exhaust gas created by depressing the accelerator, the turbo ramps up and there is an (almost) instant creation of boost. The power comes on like gangbusters. And it's possible to size a turbo---or a pair of them, with one attached to each side of a V-8 engine---so that you can achieve very high boost levels. I expect to have more than 30 pounds available.
A further thought---
If you read Quik's thread, you'll see that he did a superlative job of machining several components necessary to mount his supercharger. In order to create the two-turbo installation I'm doing, I need a chop saw, a drill press, and MIG and TIG welders, and a plasma cutter. I have these tools in my garage. Although I have access to as much machining equipment and expertise as I need, I'd just as soon do as much of it myself as I can. And I don't own a Bridgeport.
The last time my car was to the dealer was because I got free oil changes for the first 40 K mikes. I do, occasionally have somebody do work on the car, but it's because I'm too lazy to do it myself.
KS
