IMO, twin screws are easier on the block since the intake temperature is considerable lower than roots or centrifugals. Lowe intake temperatures mean a lower probability of detonation, which is really bad for your engine. But it all boils down to the tune. Also, make sure you run on high octane fuel (91+) or as indicated by the tune/supercharger manufacturer.
Why do people go around saying that the KB (or twin screws in general) best application is for "street" and that centrifugals are for "drag racing"? It blows me every time a read such statements.
As far as I know, winning drag races is all about having the most area under the power curve, regardless of peak hp numbers, and having good driving skills. IMO, that combo is unbeatable...comparing apples to apples, if you know what I mean. Let's us say that you have a twin screw and a centrifugal set at 11 psi. The centrifugal will never have 11 psi until the top of the rpm band. Whereas, the twin screw will have it all the way from around 2000 rpm to the top of the rpm band. So, having said that, why is the centrifugal better for "drag racing"? And please, show me the facts!!
Look, I realize that you're going to try to defend your Kenne Bell equipped car. I'm not trying to bash it (I love the KB system), nor am I talking out of my ass. You're getting info from a Mechanical Engineer who studied heavily in theromdynamics and heat power, fluid flow, and automotive engineering (under an ex-powertrain engineer for GM who worked on the Corvette design team back in the 80's). So don't take my comments as if they're from some teenage ricer with his mom's Civic. Thanks.
You're right, area under the curve is very important. My point is that, when drag racing, you rarely spend much time in the lower rpm's where roots and screw blowers shine most. As I said before, at high rpm's, PD blowers are not in their peak effiency and tend to begin losing boost pressure slightly, where Centrifugals on the other hand ARE at their peak efficiencies and usually produce more "area under the curve" from 4200-6200 rpms. Most don't even start making serious boost until after 3k.
Your car will almost certainly make more power off-idle and up through the midrange, making it preferred for the stop and go of daily driving. I'm sorry that I don't have the thermal efficiecies of each blower ever made but if you were to find them, the general trend would follow my statements closely.
i don't think most rousch or saleen owners give a rat's butt that x-car may be 2 tenths faster at this or that. its all about a reliable package. and the compliments. never even came close to getting as many as in my old vette, cobra, whatever i had.
I got rid of my Bullitt for my Roush because with the money I was going to put in the B to SC it & get some other stuff done & put that on a personal loan with 7% or so interest along with the payment on the B. I was better off to trade in for a new car with a SC & still have a warrantee & chaper payments in the long run.