Flow vs psi?

[Dave]

There is one problem with all of this - we're working off the standard density of air here. We're assuming the air into the turbocharger is an average temperature and an average humidity - however this is almost never the case, turbochargers are sucking red hot air most of the time! You also could be up the side of a mountain or at sea level - there's SO many factors to consider.

This is why Garrett measure in lb/min airflow which is a *MASS* airflow not in CFM which is *VOLUMETRIC* airflow. Converting between the two is not an easy process, lots of variables. That's why I say "roughly" x lb/min.

You could read for hours and hours on the technicalities behind all this. But I think what I'm trying to say is, before you instantly wang on a turbo, consider the air feed. It has to be as cool and dense as possible! If the high density wasn't there in the first place, you're pissing in the wind trying to make more power with a pissy little turbo feed.

You also have to consider that the compressor map is starting at a PR of 1 - 1 being the inlet pressure of the turbo - the outlet pressure is a ratio of the inlet to outlet pressure. This means that you could have a massive restriction on the inlet to the turbo, you'll never make much power since the turbo is still working like it always does - the less restriction you have going into the turbo, the better - it's a fairly critical part IMHO.

Sorry for my essays - I could talk all day about this as I'm sure you can tell.

Dave will vouch for me doing this in real life also.

Many conversations/discussions/fistycuffs had at the pub about pre-det and injection timing/duration/compressors and general diesel bible spewing haha