does this undermind all of the work done for the cars exaust system ect... isnt all of it like precisely tuned for the car? so could a twin turbo / turbo possibly do worse for the car than good?

and this goes along with other mods also , for any c5? :seeya

 

First to respond to a Willa post and with a serious response, man do I feel silly. :lol:

Anyway, I hadn't really reasoned through this myself before now, I had just accepted that whenever a person does a reasonable job of installing a supercharger or turbocharger on a car, the HP increases. So, now I have reasoned it through, and I will offer my thoughts.

It does seem like you're kind of defeating your purposes by installing a turbocharger on a car. You're taking power from one place (the exhaust stroke) to add it to another place (the intake stroke). Thing is, that aside from the efficiency of the turbine, that you do actually add the power that you're robbing from the exhaust stroke to the intake stroke.

Think of it this way: one piston is going up on the exhaust stroke, and it is pushing exhaust through the turbo. At the same time, the turbo is compressing the intake air and pushing down on a piston that is traveling down on the intake stroke. So, all you've lost there is in the efficiency of transfer of power from exhaust to intake through the turbo.

Now, you've lost a little bit, but not too much (and your exhaust hasn't really been affected, it's still at the same pressures and flowrates after it gets out of the turbo as stock). Here is the kicker: on a naturally aspirated engine, the only way the engine has to pull in air is by opening the intake valve and by bringing the piston down. The problem with this is that when the rpms increase, the air intake rate also increases. With intake rate increasing, so does the intake pressure drop. This means that the pressure in the cylinder when it completes its intake stroke is lower than it was when at lower rpm. So, what does that mean? Well, it means that you get less total air (lbs, moles, whatever) into the same cylinder volume. So, at higher rpm, you actually get less air, less fuel, and less power out of every stroke! The reason that power increases with rpms is because you make more strokes per minute. The reason that your power eventually drops off from its peak at very high rpms is because your air intake pressure drop has finally gotten too high - you can't get enough air in to make more power in the same amount of time as at a lower rpm.

So, what does the turbo do? Well, it's very similar to a NA car at low rpms. The turbo isn't spinning much. However, as the rpms increase, the turbo spins faster, and the boost increases. This means that the car can offset that increased intake air pressure drop, and make sure that the engine isn't starving for air. So, it can get as much (or more!) air into the cylinder per stroke as it did at lower rpms. So, with a minor loss in converting pressure from exhaust to intake, you can significantly increase the amount of power you get out of every stroke of the engine. You also decrease the intake air pressure drop, because at a higher pressure it takes up less volume and thus has a lower velocity through all your fittings! All in all, quite a nice system. :yesnod:

This should be a very simplified description of how a turbo actually gets you more power. Sounds about right to me. However, since I'm just reasoning this out on my own, others with greater knowledge of the internal combustion engine please jump in and correct anything I've screwed up. I am, after all, just a chemical engineer.

 

Yea, what he said. :D