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Ok this makes no sense. Boost is boost. 12 psi from a turbo is the same as 12 psi from a supercharger is the same as 12 psi from a vacuum. Its all just air pressure. You cant say that a turbo's boost gives you more hp but a superchargers boost gives you more torque. How is that possible. Sure a supercharger gives you more low end hp than a turbo and turbos dont max out as fast as a supercharger does but there is no difference in boost. One doesnt feed the engine magically torque air and the other one feeds the engine hp air.

 

well the fact is superchargers are less efficient than turbos because it takes engine speed to turn the rotors/blades/whatever. turbos are using wasted energy from the exhaust gases to make power and it doesnt use any engine power to spool them. thats why turbos make more power. and superchargers arent good for torque that much, but they do make good power/torque numbers lower in the rpm band.

 

You have that wrong. 12lbs of boost from a turbo will make more power then 12lbs of boost from a supercharger. Because of the draw of hp from the engine to run the supercharger. 8lbs from a SC will get you about 380 rwhp but 8lbs from a turbo will get you about 410rwhp.

To be honest the only thing this set up is good for is low end torque. You need torque to get you going fast you need HP to get you going faster after your already going. This setup is nothing new because the military has been using it for years. They have a truck called a hemit that runs a turbo to a supercharger. But its a huge truck that is ment for pulling and carrying heavy loads. On a street car its just dumb.

By the way STS doesn't make a kit for the sn95 body style because there is nowhere practical to put the turbos and they can be stolen in a about ten min if you know what your doing. I had a buddy steal one off of a 05 gt. He just cut the oil lines and unbolted the 7 bolts that held it in. Now he has a nice homemade turbo setup for cheap.

 

Ok you're right. MINUS the supercharger draw its all the same. '


But let me ask you teej281 how is a supercharger not good for torque but a turbo is??? Just doesnt make sense here. [>:]

How is the air a turbo spits out and different than the air a supercharger makes???

And dont feed me the supercharger parasidic line either. Thats about a 10 hp loss

 

I dont know. it just is. look at the graph of a kenne bell'd mustang or apaxton'd mustangand a turbo'd mustang and look at the charts. turbos make more power and more torque. dont know why. they just do.

 

A SC takes more then 10 hp to run its more like 70. Its 10hp at crusing speed but under load its around 70. Now a turbos is not free from robbing the engine of power either it creats backpressure. So it does steal hp from the engine just not as much as a SC.

A supercharger makes torque faster then a turbo because of the simple fact of turbo lag. That is why this set up is the way it is the supercharger gives it the torque and power it need to get going and the turbos carry it the rest of the way.

 

Not with a properly chosen turbo. I've got a friend with an 03 vw gti (1.8t) making 23 lbs of boost, he has ALL of it at 3000 rpm with about a half a second's spool time... redline on the car is 6250. It has lots of torque for a little 4 banger

A twin screw blower is the king of low end torque, no doubt... however, I'd say a turbo will make torque sooner than a centrifugal blower will... and hold that torque higher in the rev range.

 

Does his gti idle at 2900 rpms and he leaves a stop light at 3000 rpms. I doubt it. Even with a centri sc you will get your torque lower and faster then a turbo because it run at the engine speed. You have to wait on the turbo. Trust me I am not knocking turbos at all and I am starting a TT project but facts are facts for torque at low rpms a sc wins. And thats why I'm using 2 smaller turbos (67mm) instead of one big turbo. So I won't have the lag problems and be able to perform on the street.