The Whipple and KP (screw-type) superchargers compress air by rotating fins (or screws) . These sit on top of the lower intake (in place of the upper intake). The screws are rotated by a pulley and belt run with the accesory belt. Air comes in, is compressed by the screws and then forced down the lower intake. As stated, these make boost and a lot of power very early on in the power band - great for the street (think street light to street light where you don't necessarily have time nor room to wait for the rpms to increase and boost to come on).
Vortek, Paxton, ProCharger are centrifugal superchargers. These are units that compress the air by means of a turbine (rotating fan) and then it is forced through the throttle body and upper intake. Same principle as a turbo but instead of exhaust gases spinning the turbine, the motor spins it via a belt run through the accesories. These take a bit longer to "spool up" so power comes on a bit later (compared to the whipple) but goes a bit longer (into the power band).
By compressing the air and forcing it into the motor, superchargers create pressure (or boost). There are different levels. A side-effect of compressing the air is that it gets hotter (detrimental to performance) so intercoolers (or aftercoolers) can be used to lower the temperature of an intake charge (ProCharger does this very well).
With all superchargers, you have to pay very close attention to air/fuel ratio and timing. With the added pressures and temps, more fuel is required and timing will have to be backed out at upper rpms to keep the engine alive and healthy.
Also, different "trim" levels (think A-trim, S-trim, etc. for Vortek) are just different levels of boost the supercharger can create (due to different impeller sizes or designs or other factors) and accompanying complements for the kit. (ie. a 6 psi. kit vs. a 9 psi. kit vs. 14 psi. kit, etc.)
dont rate power by boost levels. the kits made for stock mustangs were designed and made say 5 psi on a stock 5.0 thats just an easy way to rate them
if you have heads or intake and cam etc. dont be suprised if the blower makes less boost than advertised it actually a good thing. less restriction pushing back and less heat and your still getting all the extra air from the blower just alot more effieciently.
if you throw say a 9 psi blower on a stock engine, anything you can do to get rid of restriction will be great and cause the engine to make more power even though less boost pressure is made.
boost = heat = more likely to knock
it also puts more strain on gaskets etc etc.
supercharging is generally easier and cheap. a complete bolt on kit from vortech making 8-10 psi on a stock engine will run under 3k and you can get some good deals.
a complete turbo kit costs more usually and only a few companies that offer them, they are also harder to install than a blower.
if you have some good fabricating skills you can build your own turbo system and make great power for CHEAP. this usually takes more time and harder to accomplish but if you can weld and are good with making stuff its not too bad.
one of my future goals is to get a mustang and make my own turbo setup, should be cool!
i got mine from superchargers4less.com the best price i could find. i got the SC trim kit making 5-6 psi out of the box... for right around 2000 even. Supercharger kits went up in the last year. i added an inch bigger crank pulley and boost inlet pipe and its making 9 psi.
the S trim kits making 8-10 psi out of box are less than 3k i am pretty sure last time i checked.
my blowering making 5 psi on my engine made an insane difference in power and torque. my car N/A had some guts but it would sort of fall on its face in 3rd and 4th gear, wasnt making that much power to keep it pulling hard in higher gears.
once i added the blower the power gain and the fact the blower is constantly feeding the engine. the engine doesnt have to work and the car started pulling hard in every gear. i added the boost pipe and it make 6 psi and ran a best so far of 12.16 @ 112-113. i since added a 7 inch crank pulley and in this colder weather its making 9 psi, and even builds boost faster, makes 3-4 psi by 3500. the car doesnt stop pulling at all now, it will sit you in the seat in all 4 gears with no problem and pull pretty hard, in fact traction is non existant. i am pretty sure my car will run in the 11s at the track now. i am fixing to go back one more time before the season is over. should be cool and i am hoping for the best. a blower is really fun! good luck
Question about superchargers. Do they have to be run on MAF or can they be run on 86-87 speed density.
This question is not which one would be better to run it on, but other would someone with a 86-87 speed density car (me) have to buy a speed density specific Supercharger or it would just be up to the tuner?
thx foxfan, im looking into the s trim v2 for xmas. a buddies car 302 h/c/i. gears etc. it was great but once he bolted on the s trim that car just went , the power, torque were incredable. im sold, im hoping to go 11s on the street. thx again. Ray