Boost ? regarding different turbos

[Paul Clark]

Is "X" amount of boost different if produced from turbos of different sizes?

 

[JadeMonkeyStang]

Well basically, smaller turbos are less efficient at higher boost, so they're producing more heat at a given boost level. While either one might be generating, say 26lbs. of boost, a larger turbo will be keeping the air charge cooler. This cooler charge is denser so you're making more power at the same, or possibly even a lower boost level. That's my understanding at least, anyone may feel free to correct me.

-Jade

 

[ijames]

Jade got the most important part - the bigger compressor wheel is most likely more efficient and so heats the compressed air less for the same boost. The other side is also important, though - a bigger, more efficient turbine wheel puts the same horsepower to the compressor wheel with less exhaust backpressure so the pumping losses are less. In other words, with the same boost and intake charge temperature, more air will flow through the motor because the exhaust restriction is less for a bigger turbo. Think of the TE60, 61, and 62 turbos - same compressor wheel but progressively bigger turbine wheels, for progressively more and more power.

 

[Sinful6]

I'd say the major thing is that the larger turbo flows more air(rated in CFM) than the smaller one. Then of course, the heat efficiency of the turbochargers.



-DC