Simple... a "hot expanding gas" as you put it, spins the turbine. All gasses have mass, an increase in this mass in an area that does not increase = an increase in pressure.

 

very good, now if the "air speed" is sped up as it drastically is right after the exhaust port due to the expansion of gasses in a small area, the increased velocity is what actually spins the turbine wheel. So when the turbine is put far away from the manifolds restrictive high velocity "expansion chamber", the air slows way down and is not very efficient at turning the turbine wheel.

This is as simple as I know how to put it, if you want a better explination, there are tons of them out there that you might find that makes a little more since to you.

 

So G.T.F.O.

 

I thought the turbine "scroll" increased the velocity of the gas as it passes through an increasingly smaller dia. heading toward the exit. So, if you have a given pressure on the entrance side of the turbine, and the velocity of gas increases through the scroll but the pressure stays the same, then the pressure drop is caused from both the increased area after the turbine and the work done by the heat energy that turned the turbine wheel.
No???

 

Yes, the turbine works off of pressure. Heat makes it more efficient. There are a lot of improvements to be made to the system... Ceramic Coating on the exhaust would help as would header wrap, foil, and thermal insulation... combine all and it should keep a significant amount of the heat in the exhaust.

I've been researching intercooling and there is a way to get a air-to-water intercooler installed up front.

There is still GOBS of backpressure in the exhaust but it is an interesting topic to research. Some of the backpressure will be bled with the wastegate but there is still a significant amount which will affect reliability and mileage.

 

Yes. Regardless of the amount of power an engine is producing; the closer you are to the head, the more pressure you have to work with, because the gasses are hottest and hot things really enjoy the whole "expanding" thing.

 

Agreed! Plus, closer to the heads with hotter gases allow you to operate with less exhaust backpressure due to more available potential energy. However, the numbers look decent for the STS... FYI- they are going to the dynos in Cali in March for CARB approval. I heard they will have 3-4 vehicles on the dynos.

 

I guess some folks just can't seem to understand that there are times when it may be desirable to trade efficiency for something else that you want.

 

I am not a turbo expert, but from what they are stating they size the turbo just for using it at the back of the car. They say that if their turbo were to be used at the front, then it would have massive lag. Sounds like a good idea, doesnt have to use custom manifolds either, which is cool. Probably could use regular headers.