turbos??

[RD]

i was browsing through ebay and came across turbochargers... i am confused on something.. what do these numbers mean?  I am forced induction stupid so please go easy on me.

60 A/R Compressor
.63 A/R Turbine

50 A/R Compressor
.63 A/R Turbine

they are two different turbos, i am guessing this is the ratio of one impeller to the other 

[Rolling_Thunder]

A/R = Area over Radius...   

[RD]

which one of these will create more boost or not? what is the advantages of one over the other? and thanks for the reply RT

[c00nhunterjoe]

its not about boost pressure, its about air volume.  a turbo on a honda civic might put out 25 popunds of boost, but the turbo in my truck flows more air at 10 pounds of boost then that civic does at 25.

[RD]

its not about boost pressure, its about air volume.  a turbo on a honda civic might put out 25 popunds of boost, but the turbo in my truck flows more air at 10 pounds of boost then that civic does at 25.

cool.. can you tell me which one has more volume then?

[Rolling_Thunder]

the one with 60 A/R on the Compressor...   

Compressor A/R ratios are what dictate rpm usage...    lower numbers = higher boost           Larger numbers = lower boost

The A/R ratios on the Turbine = Using a smaller A/R will increase the exhaust gas velocity into the turbine wheel. This provides increased turbine power at lower engine speeds, resulting in a quicker boost rise. However, a small A/R also causes the flow to enter the wheel more tangentially, which reduces the ultimate flow capacity of the turbine wheel. This will tend to increase exhaust backpressure and hence reduce the engine's ability to "breathe" effectively at high RPM, adversely affecting peak engine power. Conversely, using a larger A/R will lower exhaust gas velocity, and delay boost rise. The flow in a larger A/R housing enters the wheel in a more radial fashion, increasing the wheel's effective flow capacity, resulting in lower backpressure and better power at higher engine speeds.

Compressor = snail shell that brings in cool air and outlet goes to intake manifold
Turbine = Snail shell that in placed in exhaust track to convert exhaust pressure into a spinning shaft connected to the Compressor.

So depending on your application you can choose a better turbo...    if it is a low boost ( say 7-10psi) you'd want the 60 A/R Compressor / .63 A/R Turbine system...    if higher boost (15+psi) you'd want the other.

[RD]

RT, wow!!! totally makes sense now!! thanks so much! i dont know jack about this stuff and it just piqued my interest and well.. you done did explain'er now didntcha?

thanks again man, i love a good education.

[motorcitydak]

If you are serious about doing a turbo, get the book 'Maximum Boost' by Corky Bell

http://www.amazon.com/Maximum-Boost-Turbocharger-Engineering-Performance/dp/0837601606

[mauve66]

go big or go home, F1 all the way dude

[motorcitydak]

FTI, all motors already operate at roughly 14.7 psi. Just about any motor can take a 5psi system. It will add 50-100hp depending on motor size and efficency. If you start going over that, plan on upgrading the internals and fuel delivery system.