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soundcolor -> RE: Supercharger/Turbo: suggestions anybody? (3/8/2007 11:44:26 AM)
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ok, since everyone seeems to want me to give really long, dull and complicate responses. Here is a quote from another post I entered on feb. 24th.
"Superchargers work at very low compressor effeciency, with the absolute best you are ever going to get being about 60-65% effeciency,
Turbos however experience alot less turbulance, and since the air they are moving doest have to be compressed in the unit (rather compressed through the piping and intercooler (if there is one) then that air doesnt move back across the turbo to slow it down,
Roots type superchargers (regardless of whether its an eaton, whipple, or lysholm) all use basically an air resovor chamber with two big fat/long blad fans spinning either in the same direction, or across it. They rely on the small gap in between the blades to compress the air, and shoot it back out. However since most of the time they are bolted directly to the head, or have very little piping, it just doesnt leave anywhere for the air to go, except to stumble back around, and stay in the chamber, until the throttle body opens, and it can flow into the cylinders. Because of this, the air in the supercharger can coninue on its cycle inside the unit, and get re-heated, as it tries to re-compress, which only equates to less hp, as we all know heat makes less power than cool.
As for Centrifugal superchargers, they are generally where you are going to find the higher compressor effeciency numbers, as superchargers go, (typically closer to 65%) However there main problem is that unline a supercharger, they require something to drive them off of the engine, and whatever is used to drive them, takes power away from the motor at the same time the supercharger adds it. Centrifugal superchargers have very similar boost charicteristics to turbos, however because all of the boost perameters are set at the design stage with gearing choices, then there is no other way to make more boost, without a smaller pulley. Where turbos only require a turn of a dial, or at worst, loosening a screw and turning an intergrated wastegate actuator control arm father in. Centrifigal superchargers have a limit. They spin very fast, and have little tolerance for being spun any faster. Not only that, if you decide you want more boost than the unit is capable of, often times the only option is to replace the whole unit. Which leads to horrible long lag times as the unit moves to a speed that it can become usefull.
Turbos on the other hand have none of those problems, as they can, and for the most part are designed so that the turbine side is smaller than the compressor side, so that it spins up alot faster than the compressor. The reason for this is so that you can have your lotsa boost, and so that you dont have long lag times.
Dont get me wrong, turbos definatly heat the air there fair share, but it is considerable less than any supercharger ever will. Also, intercoolers do alot to be able to chill that air back down to almost ambent temps.
and just for the record, turbos have compressor effeciency typically around 75 to 80% "
Since you are askin what is best for you car, and not really telling us anything about your plans for the car, then the best advice I can give you is to go with a turbo, on your particular car, and with your particular motor, a turbo will be fairly straight forward to install, giving you a very noticable boost in performance. It will also allow you in the future to upgrade as you upgrade the rest of your engine setup. When you are ready to go to the internal of your motor, the turbo will still be there allowing you to turn up the boost and make even more power. On your particular car, RIPP Modifications make some very nice supercharger kits, go to http://www.rippmods.com/products/products_list.asp?menuid=3&vehcId=2 for info. If you are looking for good turbo kits for your car, go here, they have some nice stuf.. http://www.turbo-kits.com/eclipse_turbo_kits.html
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