So people say that 10 psi on turbo A is not the same as 10 psi on turbo B. I though psi was a measurement of air pressure. As long as turbo A and B are both pushing 10 PSI, how can it make more or less horse power? How can it be safe to run 10lbs on turbo A, but not ok to run on turbo B?

 

Larger turbos flow more air at the same psi.

 

theres 2 things involved...one is boost pressure the other is cfm of air flow....

 

larger compressors are more efficient at certain boost levels than smaller turbos meaning they heat the air less after being compressed at a particular boost level. Cooler air is more dense and makes more power. Also larger turbines are less restrictive on the exhaust. Less backpressure means more power and less exhaust gas reversion.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SOHC_MShue &raquo;</TD></TR><TR><TD CLASS="quote">larger compressors are more efficient at certain boost levels than smaller turbos meaning they heat the air less after being compressed at a particular boost level. Cooler air is more dense and makes more power. Also larger turbines are less restrictive on the exhaust. Less backpressure means more power and less exhaust gas reversion. </TD></TR></TABLE>

perfect

 

he nailed it.

 

Compressor efficiency generally plays a relatively small role unless you are taking a very small turbine and spinning it very very very fast. I answered this question a few weeks ago. Maybe you can dig it up. It more or less has to do with larger turbine, less reversion, increased VE, thus allowing more volume, thus causing the turbo to flow more air to keep the psi constant.

https://honda-tech.com/zerothread?id=1633516

 

Thanks guys. Very helpful.