[Ensit Mike]

Ok so my question is what makes one company better than the other. Ex Kenne Bell and Vortech.

I've been researching s/c's for a while now and i still dont get why people say some are better than others. For example what are the advantages of having a big bore twin screw Kenne Bell super charger putting out 9 PSI over a Vortech H/O putting out 9 PSI. If they are both putting out the same PSI arnt they both making the same power gains? The only difference i could see is if one had a better intercooler because i can see how one could cool the air more efficiently.

With this im talking only about power gains...because Kenne Bell does have some great stuff like bypasses and the ability to quick change pullys.

Thanks
-Michael

[HMUSN]

the supercharger you get is based on what you want the car for.

2 types..

roots stlye
IE:

KB
Whipple
Eaton

and centerfugal

Vortech
(there are others but they slip my mind)


the roots style produces instant boost while the the centerfugal type has to bluid boost(similar to a turbo)

the centerfugal can produce more boost than a roots type though

[TheUNZippee!]

Exactly. Basically what you are looking at is, Roots style = more bottom end punch, while the centrifugal style = more top end power.

[Ensit Mike]

They arnt both belt drivin? Sorry if this sounds stupid but if the RPM of the s/c is going the same as the engine how does one create more than the other?

[TheUNZippee!]

They are both belt driven, yes. But the roots creates pressure differently than the centrifugal. The roots style uses splined rotors, or lobes, in a housing with very low tolerances to create pressure, while the centrifugal uses a shaped housing that creates pressure as the air is forced through it.
I have a magazine around here somewhere that has a cool article about this in it, I'll see if I can dig it up so I don't wind up talking out of my ass.

[TheUNZippee!]

Roots
The roots type supercharger is two counter-rotating meshed lobed rotors. The two rotors trap air in the gaps between rotors and push it against the compressor housing as they rotate towards the outlet/discharge port. During each rotation, a specific fixed amount of air is trapped and moved to the outlet port where it is compressed, which is why the roots type supercharger falls under the broader catogory of fixed-displacement superchargers (like the twin screw supercharger).
The roots type supercharger is known for its ability to produce large amounts of boost while spinning at very low speeds. On an automotive application, a roots type supercharger can often make it's full (peak) boost by 2000 engine rpm. This characteristic has contributed to its success and popularity on the top fuel racing circuit and has made it ideal for use on smaller 4 and 6 cylinder engines that traditionally struggle in the lower half of the rpm range (and is why Jackson Racing uses a roots type Eaton compressor). Another advantageous characteristic of the roots type supercharger is its simplicity of design. The roots type supercharger has very few moving parts and spins at low rpms, making it one of the more reliable and durable supercharger designs.
The big disadvantage to the roots type supercharger is its thermal inefficiency - or its nature to produce high discharge temperatures - which robs power from the engine. With a roots type supercharger, an intercooler is almost always a necessity to bring the air charge temperatures down to an acceptable level. This poor thermal efficiency can be attributed to the fact that it has no internal compression (compression is done after the air leaves the discharge port). Additional heat is created by compressed (hot) air that leaks backwards past the rotors and heats up the temperature of the inlet charge.

Centrifugal
The centrifugal supercharger essentially operates like a high speed fan propeller / impeller, sucking air into the center of the supercharger and pushing it to the outside of the rapidly spinning (40,000 + rpm) impeller blades. The air naturally travels to the outside of the blades because of its centrifugal force created by its rotating inertia. At the outside of the blades, a "scroll" is waiting to catch the air molecules. Just before entering the scroll, the air molecules are forced to travel through a venturi, which creates the internal compression. As the air travels around the scroll, the diameter of the scroll increases, which slows the velocity of the air, but further increases its pressure.

The centrifugal supercharger enjoys several advantageous characteristics that make it the most popular supercharger design in the aftermarket world. First, it is simple and reliable because it has very few moving parts - just a few gears and the impeller. Second, the centrifugal supercharger produces very little heat because of its internal compression ratio. It is also small in size and very versatile because it can "free-wheel" and allow the engine to suck air through it or even flow air backwards. For this reason it can be placed anywhere in the intake tract - it can even "blow through" the throttle body, meaning it can be mounted nearly anywhere. It is also the most thermally efficient supercharger, meaning that it produces the lowest discharge temperature.
The only significant disadvantage of the centrifugal supercharger is that it must be spinning at a relatively high speed before it begins to make a significant amount of boost. For this reason, it is not helpful in creating boost (and power) at low engine rpms. Normally the supercharger only begins to create boost at around 3000 rpm, and the boost curve gradually and increasingly rises with engine RPM. Many centrifugal superchargers do not have a self-lubricating oil system, and draw oil from the engine's oil supply. The disadvantage to this is that you must tap the oil pan for the oil return line. However, in doing so, the supercharger becomes virtually maintenance free. Some manufacturers make a "self-contained" centrifugal supercharger that is self-lubricated like roots and twin screw superchargers.

[Ensit Mike]

Wow Thank you so much that answered every one of my questions. So I am deffinatly going roots because I love instant power at my foot =]

Thanks again that was great

[TheUNZippee!]

My pleasure man. Let us know how the new huffer works out for you.

[BWAL]

what about twin screw? nobody ever mentioned that type.. kenne bell is a twin srew supercharger..

[TheUNZippee!]

The twin-screw supercharger is a positive displacement air mover, which means it moves a fixed amount of air per revolution, like the Roots-type blower.

[TheUNZippee!]

I just found a cool web site with all kinds of information about superchargers.

SuperchargersOnLine

[Stkjock]

love my Vortech.... docile when you want and a beast when you need it!!!

435 RWHP!!!

[VegasGT]

Originally Posted by TheUNZippee! Exactly. Basically what you are looking at is, Roots style = more bottom end punch, while the centrifugal style = more top end power.

I agree only because you compared to roots. Twinscrew does have top end.

[VegasGT]

Originally Posted by HMUSN the supercharger you get is based on what you want the car for. 2 types.. roots stlye IE: KB Whipple Eaton and centerfugal Vortech (there are others but they slip my mind) the roots style produces instant boost while the the centerfugal type has to bluid boost(similar to a turbo) the centerfugal can produce more boost than a roots type though

Whipple and KB both are NOT Roots! Bad info!

[VegasGT]

To see the difference between the two:

http://www.kennebell.net/techinfo/ge...romcatalog.pdf

[MaverickMLFD371]

whipple and KB are twin screws, whoever said they were roots needs to re-read or re-study about superchargers before they say something like that.

still love my whipple twin screw putting down 475RWHP!