rraulston

iTrader: (2)

Man, i have read hundreds of posts about turbo kits and just keep getting confused. A larger turbo moves more volumn of air, right? How do you figure. If the stock turbo boosting 19 psi filling 3cf of pipe and intercooler, how can a larger turbo boosting 19 psi filling the same volumn of space move more air. The space is the same!! The density is the same at 19 psi. The only difference i can figure is that the temp would be a varible. Yet even with a lower temp, i wouldnt think the difference would be substantial. So the larger turbos do make alot more power, i have seen it. Ime just trying to understand the physics of it. Ime hoping that will help me make up my mind. I think ill just find someone who ran a high 11 and clone their setup.... RRR

chuntington101

From what I understand (and that’s not a 100%) generally a lager turbo will move the same VOLUME of air more efficiently (ie impart less heat into the air). Don’t forget that it is flow you are after not pressure, to make more power. You can get to a point with a turbo where you are increasing the boost pressure and not making any more power! This is because all you are doing is increasing the temp of the air (due to over running the turbo), and therefore the pressure, and not actually “moving” any grater volume. This is when a larger turbo is needed.

I think this is right but I not sure. Anyone else have any ideas?

Thanks Chris

Jadiem

iTrader: (6)

think of it like this... blow through a straw, like a drinking straw.... lets say when you blow, your blowing 19 psi.. now grab a 4 inch pvc pipe, blow through it.. now it's gonna take more force to create 19 psi in the pipe, therefore you increase the force and the psi is matched...

DystopiaMagnate

Try https://www.evolutionm.net/forums/sh...e=2#post984647 and see if that answers any questions.

In the case of compressors, a larger compressor will be sized so that it can pass and compress greater mass flow without choking vs. its smaller counterparts. The points of peak efficiency in the larger compressor will shift right on a compressor map, toward greater mass flow. With comparable aerodynamic design technology and techniques, you will also see the peak efficiency values go up with increasing compressor size. This is because the relative aerodynamic penalties go up in severity as you decrease the turbomachine size.

With turbines, again it's a question of flow capacity, if you will. If you choke the turbine too far before redline say, you're eating a big fat backpressure sandwich and burning power.

If you're comfortable with the basic ideas behind compressor and turbine maps, go take a look at something like the Garrett catalog to get a feel for things: http://www.turbobygarrett.com/turbob...%2017%2013.pdf