Back pressure is a pumping loss and therefore is also a parasitic loss. Turbo systems operate most efficiently when the backpressure resulting from the turbo is equal to the pressure of the incoming charge. This comes in well before most turbo kits reach full spool so for the vast majority of operation the engine is pumping against an increasing backpressure. A properly sized turbo will minimize but NOT eliminate this situation. So in anycase a turbocharger will take power to make power for the engine...there is no such thing as free power here.

 

I recently read that an engine's power is 1/3 out the exhaust, 1/3 dissipated as heat, and 1/3 does the work. If this is the case, then the 1/3 out of the exhaust, aside from the back pressure or pumping loss, sounds like the way to go. A loss of 10 - 15 hp is a lot better than the 70 - 75 hp loss with a blower.

 

Actually it's a bit less than 1/3 does the work. There is efficiency loss in the very act of combustion that is beyond recovery even in idealized (no friction, perfectly adiabatic, etc.) systems.

 

I still wont agree that the loss you get in a well matched turbo setup, is anything near "parasitic loss" like you see with a supercharger. There are so many factors that a real set amount is difficult to determine..

I think it's safe to say when debating between the two superchargers, saying the turbo has "almost no" parasitic loss is a fairly safe bet.

 

how will this turbo system work on a 2000 ford expedition?

 

just like it will on all the other trucks.

 

In case you missed it...


A loss is a loss is a loss.

 

HI!... I remember reading somewhere that to make 600RWH.P, a ROOTS/SCREW style SC'er needs 125 flywheel H.P just to spin it. A turbo making the same 600RWH.P only steals 15 flywheel H.P. It's still a loss but no where near the loss of a positive displacement SC'er.

 

well in that case, anything you do to a motor causes a loss..... Eating a cheeseburger causes a loss due to the extra weight

It's fun to live in the "well technically" world huh?

 

i dont care what kind of loss i have, but I Have enough power to make up for that loss. Why go into so much detail here?

 

What world do you live in that motors eat cheeseburgers

 

Because that's what we all do here.

 

I live in the "sweat the details" world. Little extra knowledge goes a long way huh?

 

Here are the curves on the Eaton M112, (Roush, Powerworks, Trilogy, etc.)

 

throw a cheeseburger in and wash it down with some sea foam. All the kids are doing it these days.