[Normy]

Wow...

Well, Erik, if you work your way down to Florida again...remember, my original offer stands. If you want to take my 928 for a few days down to the keys, it's yours. But I expect a full tank of gas when I get home...

Anyway, I still don't understand all the fighting. Supercharging is supercharging, whether it is powered via belt or exhaust gases. Sometimes I think that people personify technology; that is, if they purchase one type of equipment, then they somehow feel that people that purchase the other type are stupid or inferior or less informed. It probably goes even deeper than that. People actually identify with certain types of technology, and develop a "block" towards alternatives. I find myself doing this exactly with pushrod valve trains. For some reason I find this feature so bizarre and backward that I won't even consider buying a car from the main proponent of this technology, the general motors corporation.

[see! I didn't even capitalize that proper name...]

You get the idea. I've come to the conclusion that we, members of our species, have a decided tendency to "pick sides".

Twin screw: Instant power, though it probably isn't as efficient as the C-fugal blowers. Great fun if you love to leave stop lights RIGHT NOW. Downside: Wheel hop. 928's have IRS rear suspensions, and these aren't the best for transmitting high amounts of torque quickly. And it has a belt dragging against your crankshaft, putting wear and tear on the front engine bearing. And I read that the Eaton blower that Ford attached to the supercharged V6 Ford Thunderbirds could use up as much as 45 horsepower at full RPM...

Centrifugal: Perfect if you want to autocross. The power builds gently, so you can enter a curve and not have to worry about a gas pedal that is so "sensitive" [remember, instant power...] that it causes you to mess up the balance that you've worked to maintain so that you don't understeer. The problem is... it still needs to spool up, and you are of course subject to that BELT. And it uses horsepower. See above-

Turbocharger: These use an impellor spinning at speeds of upwards of 100,000 rpm to produce boost to the engine. The impellor is small, but it still needs a second or two to reach the sort of speeds where it will produce boost. Not the hot tip if you are exiting a curve on a race track, and want instant torque right now to get around another car. Also, if the turbo spools when you are not expecting it...it can lead to something that bit a friend of mine: Oversteer. He drove his T-bird turbocoupe into a tree when we were in college when the big turbo on his four-cylinder finally spooled up, and the sudden torque cause the car to violently oversteer, right over the curb and right into a maple tree. Turbo's work when they want, not when you want them too, and that is the problem.

-If I were going to boost my car, I'd probaby ask John or Mark down in Austin to figure out a way to fit a turbo. Why? Simple. I like the way that power builds with a turbocharger- it is a great rush, and I'm not racing my car [yet...]. The torque starts soft, and then builds...and builds, and then the car basicaly goes berzerk. I love that effect! I'd own a 951 if they sounded like a 928 with a good exhaust and well, looked like a 928!

See? It is purely personal preference. Andrew Olson loves his Detroit-style "stomp it and go" twin screw, and Erik probably prefers his centrifugal blower because it is best for autocrossing. John just likes the technical challenge of designing and building what amounts to an OEM-spec turbocharger system on his Porsche. We're all having fun right?

N