I've been trying to track down what I think to be a boost or exhaust leak on my 2008 A3 (TSI motor) - for the past 6 months. I'm Apr Stage 1, everything else is stock except a high flow air filter. Upgraded to Rev D DV Valve. (FYI - i started to notice louder turbo spool before the tune which prompted me to upgrade the DV with no change in loud spool noise)
At this point im not sure it a boost leak because I've pressurized the system to 12 PSI with no apparent leak. (my home made leak tester started to leak at 12 PSI so I couldn't test higher). My turbo spool sound had gotten progressively louder over the last few months to the point where I can hear it with my windows up. It's most noticable during initial spool up which seems to be taking longer also. As you can see by my logs, my N75 duty cycle is very high, only dropping from about 3k rpm to 4.5k rpm.
Even in stock mode, I can hear the turbo spool loudly. I'd like some comments on the attached log... I've got the Micro-Can connector so my data resolution isn't all that great.
I'm not sure what my airflow should be at stage 1, but 165 g/s seems low which makes me think I have an exhaust leak and the turbo can't spool properly even with the wastegate fully closed...
BTW - I'm at 2400 foot elevation and the ambient pressure here is about 920 mb. Air temperature at time of logging was 91 degrees. This was the first run after a slow freeway cruise, so I don't think heat soak was an issue.....