Apparently the teflon coating is damaged by fuel so a draw-through system can be bad. I dunno, just read it on the net.

The roots type blowers as per SC12 and Eatons are low efficiency so the heat up the air more than other types. I have an M45 on my MX5 and it is operating outside of it's peak efficiency running an 1800cc engine. On a 1600 or smaller engine it will be closer to peak efficiency but that is still lower than 60%. Other types get much better efficiency but screw compressors are much more $.

The P1V1T1=P2V2T2 rule is for adiabatic compression which is not what happens inside a roots blower and manifold. T2 is much higher than predicted (and related to the efficiency of the unit). Expanding the compressed air to lower the temperature is counterproductive and just means you over-compressed it in the first place. You have to cool the charge or add a liquid that will absorb the heat as it heats/vaporises.

I may not have built many engines in my time but the laws of physics don't change.

M