ok I've heard so many times that when you put 1BAR of boost with a turbo that you double your engine power , my friend build up a 3000gt and did just that and it was 4 HP's off ! but my cousin supercharged his S2000 and when he set's it to 14.7 , he only get's 413HP ! If My Calculation is right , 240HP times two gets you to 480 ! but on the 3000GT , wich was already turbo we took off the original turbo setup of the car and got the engine Dynoed : 246HP the he put another Single Turbo kit in and set it to 14.7 and got 488HP ! my question is : does the 1bar formula usually work for superchargers too ???

I guess it really depends on engine effeciancy.. atmospheric pressure is 1 bar.. or 14.7 PSI.. now if you run 14.7 PSIG (guage pressure), you will have twice the ambiant pressure.. I forget my volume formulas.. but this may or may not mean double the actual air..

can anyone with a chemistry backround please elaborate? I didnt pay attention to the stuff like that! :S

it all has to do with how effeciant the engine is.. like you can try cramming 10L of air through a 5L engine, but if the engine wont flow it, you wont get the power! ya know? now, if you had the engine ported out and polished nicely and the intake bored out nicely, and a TUNED turbo header and such, you would be well on your way..

haha.. Im just thinkin.. a few of my friends from highschool were the "honda guys" and I saw them just recentally.. appearentally they were runnin 7.5 PSI on stock 1.5L honda SOHC civic engines..

both of them blew head gaskets and burned pistons the first day they had them! whell, back to the story.. those are great little engines.. but the turbo manifold they BOUGHT was a joke! if you are going to spend the time to have one made up, go equil lenth.. its well worth it..

also, superchargers work a little differentally.. they take some power to make power.. turbos dont take any power away from the engine (not NEARLY as much as a supercharger!).. just remember, your alternator takes somthing in the area of 12HP to drive.. so imagine what compressing a whole whack of air to 14 pounds would take! and from what I read, 14 pounds is ALOT for a supercharger.. most of them run about 5 pounds.. oh.. and another thing I almost forgot was if you are using one of those roots type blowers.. like an EATON used in the Jackson Honda stuff, they beat the heck out of the air while compressing it, so you loose ALOT of effeciancy (?sp?) there. if it was a "centrifical supercharger" like a *brand name escapes me right now* (looks like half a turbo), those arent as bad.. but give very peeky power..

also, was the turbo intercooled? was the supercharger aftercooled?

that could make a real difference..

whell.. hope I helped ya a little bit!
jude

In an idea world, with the engine achieving a 200% VE it would make twice the HP with 1 BAR. However, this is not an ideal world, and you run into the law of diminishing returns when you play with boost. Things such as charge heating, head flow, and power loss from driving the blower will reduce the actual output from the 2x mark.

Now as for the turbo vs supercharger debate, they both will create about the same power output. While a supercharger will take power from the engine to run, a turbo will take a substantial amount of power as well. If you ever have tried driving a car with a turbo installed but not connected to the intake you'd know what I mean. Turbos use exhaust gas to compress the air, this creates a large amount of backpressure in the engine. Backpressure makes the engine work harder to push exhaust out, which reduces its power output. Also, 14 psi of boost is just as easy to make with a supercharger as it is to make with a turbo. As was said before, if you use a centrifugal supercharger (a Procharger for example) you basically are taking a turbo and driving it with a belt. With a supercharger, turbo lag is eliminated, since theres no "spooling up" involved. Although boost still does need to build with a centrifugal supercharger, roots and screw blowers will make pretty much the same amount of boost over the entire RPM band.

[This message has been edited by PontiacMan (edited 04-10-2004).]