brider

Did a search under "turbo", didn't really find anything:

Can anyone explain the turbo operation on the 2.7T motor? When, or under what conditions does the boost occur? Is it boosting even at low rpm's? Is there a way to alter my driving habits to activate/maximize/minimize the boost?

I'm not have any issues regarding the turbos (156k and original), just wondering when they're operating.

thejulex

Realistically they're operating all the time as their turbines are directly in the exhaust stream. You can call it "turbo idling" if you want. In that mode there isn't enough velocity and volume in exhaust stream to power the turbos to generate positive pressure on the compressor side of shaft. The turbos spin relatively slow.

Depending how much you step on the pedal, the more you do the more air travels through engine and the faster/more air travels through the turbos. Somewhere along that curve there is enough force behind all that exhaust gas for turbos to overcome resistance on the compressor side and the turbo starts compressing the air.

You can't really tell what that spot is unless you run some kind of pressure gauge connected to intake manifold or logging software that can read engine's pressure sensor to tell you that you are running positive pressure in respect to atmospheric pressure.

When k04 turbo are running full steam on stage 3 2.7t engine @ 20+ psi of pressure, they spin at about 150,000 rpms. I would imagine that k03 turbos like yours would spin somewhat slower running stock pressure.

If you really want to read in detail how all that works in our engine:

http://www.ibiblio.org/tkan/audi/2.7...-SelfStudy.pdf