Re: Of Long Posts and Superchargers...
Originally Posted by waldig
At a boost level of 20 psig I am figuring that we are at a pressure ratio of 20 / 14.7 or 1.36??? Some one wanna whoop up on my head ann edkate me. If it is 1.3+ thats low on the map.
at 20psig boost, you are at (14.7+20)/14.7 or a 2.36 pressure ratio.
Teflon decomposes at 260 degrees C. Lysholm engineers have been quoted as saying that the blades of a screw-type compressor will bend before anything else on a compressor fails. That's from Lysholm, I'm not sure what the guarantees on an IHI compressor are.
Regardless of air temperature, the volume airflow of the compressor is fixed. Low compressor efficiency means the resulting mass airflow decreases. 50% compressor effiency @ 20psig means 21 deg air is compressed to 165 deg C. This is computed using the formula of adiabatic air expansion.
In reality, this is probably a loss of anywhere from 20-30 hp, which is just a guesstimate based on a relatively inefficient intercooler (50%). If the intercooler were more efficient, then the actual loss due to temperature would be even lower.
My understanding: The lack of big numbers mostly comes from the fact that the compressor is undersized for operation at 20psi. If the compressor were sized to match, I'm sure 440+ at the wheels is possible.
Last edited by sonoronos; Jan 23, 2009 at 05:35 PM.