Why does Superchargers make good HP but less Torque than a single or twin turbo setup? Would having a built engine with higher compression pistons help this?

 

The supercharger makes it's peak hp at max useable rpms. The faster the engine is revving, the faster the supercharger spins the turbine, the more boost you get, the more hp the car makes. The turbos make there boost earlier, and can get a good hp reading by 3500 rpm, or so. This creates more torque, because the engine is getting the power in it's peak area. The boost then levels off, or sometimes drops a little, depending on kit, all the way to redline. So a kit that makes 11 psi of boost will make more hp and more torque than my kit at 11 psi. I see 11 psi at 7200 rpms, in the power band, I see around 5-8 psi. I hope my rambling made some sense.

 

thats a good question... is there more area under the tq curve on similar peak hp/trq turbo or SC? I've always wondered. I'm a big fan of area under the curve.. (im an engineer major lol)

 

with the supercharger running off the crank shaft, it will always spin only a certain amount faster than the motors rpms.(just using the centrifical supercharger as example) it is a linear equation that will always be constant. the turbo on other hand, can reach it's full boost depending on engine load and not engine speed. thats why you can see full boost at a much lower rpm.

 

As a slight aside, torque and power are related as:
power (BHP) = torque (lb ft)*rpm/5252

so the power and torque curves should ALWAYS cross at 5252rpm and
i) power is ALWAYS less than torque 0<rpm<5252 and
ii) power is ALWAYS greater than torque 5252<rpm