Injecting prior to turbo comp' impellers

[leman_opc]

Thanks for the detailed explanation on this.

Based on what you say I assume with preturbo injection the result may be close to the following options:
1. Boost decrease but virtually no gains in air consumption (in case of restrictive hotside being an issue), or
2. Unchanged boost but increased air consumption (in case the hotside may still flow the increased air mass)?

[Liborek]

Originally Posted by leman_opc

Thanks for the detailed explanation on this.

Based on what you say I assume with preturbo injection the result may be close to the following options:
1. Boost decrease but virtually no gains in air consumption (in case of restrictive hotside being an issue), or
2. Unchanged boost but increased air consumption (in case the hotside may still flow the increased air mass)?

I assume that your setup is intercooled, correct?

Intercooler is very efficient device and it largely diminishes difference in temperature of charge air which would be caused by different compressor efficiency, so when you measure some absolute pressure and temperature in intake manifold, you know it has certain density and it doesn't matter how this state has been achieved.

So don't dwell that much on airflow number. Setup without intercooler would produce more obvious difference in power in regards to position of water injection.

Engine net brake power isn't just about combustion of air and fuel, but also about minimizing losses. Very high back-pressure not only impedes airflow, but its also direct negative work for engine. Unfortunately, I really don't know how much power could be "freed" in reducing one, some complex engine simulation could do it, we must live up with just performance testing :-)