Turbos will give the most power and quickest track times. The turbo and centrifugal superchargers (basically a belt driven turbo) will continue to build power as the go through the 1/4 mile. They take longer to build power and torque though.
So it isn't enough to say "turbo for track and supercharger for street" because of the similarity of the turbo and centrifugal supercharger. The centrifugal is more street friendly than the turbo though, and the turbo is still tops for power.
The roots type of supercharger has more torque down low in the rpm, which makes it great on the street. But at the top end of the 1/4 mile it can't make any more power and the turbo and centrifugal can run it down. I always can get out quicker than my turbo friends, and they usually can run me down; the difference is I can run mid 12's at best and they can run mid 11's. The only roots type - positive displacement - for the 4.0 is the Explorer Express Xcharger.
---------- Post added at 10:24 PM ---------- Previous post was at 10:21 PM ----------
Originally Posted by Eturner
Actually yes it is!.. You get a positive displacement SuperCharger, like a Eaton or Kenny Bell!.. And feed it with a Turbo or two!.. Check out some of the kits from Hellion!..
KenneBell doesn't make a blower for the 4.0. And you actually wouldn't feed the positive displacement with the turbo since the positive displacement blower starts out making power right away, while the turbo needs time to build boost. With a dual system the positive displacement has to feed the turbo to spool the turbo up quicker. But then the blower becomes the bottle neck in the system. It is possible, but not an easy balance and a real trick to tune the set up; which is why you don't see it often, tuning and balance plus the bottle neck messing with the flow of air.