its the vaccum, once it builds up suction it will quiet.......but these things sure are loud also when the a/c is on....

 

This is just the warm up phase. Since I'm a mileage snob i have experimented with this. What happens (observation and experiment ....not facts) is that the car dosen't settle into its normal idle for about .25-.5 miles or 90-120 seconds...give or take . What you can do to feel this out is go to a flat parking lot, set the instant mpg, and see what happens when you put it in 5th after getting up to 10mph or 12mph (step your way through 1st, 2nd, 3rd, 4th super quickly). Yes that is slow, but after the car has been off for a while (all day) it will pull on its own to 20mph or more...lol. This will not happen once the car is warmed up,(stall it if you like). Your instant mpg will read obscene numbers like 2mpg-5mpg for the time it is in this "period". Then magically the car will settle, the mpg will rocket to 25+. I can gain mpg (remember the mileage snob) by parking uphill and in the direction of my route in the morning to work, I dont hit the gas, and i just let the clutch out slowly, the car will pull itself to almost 20mph sometimes in the flats/slight downhill. My instant mpg will be double the normal warm up 6-14mpg and the normal "mode" seems to kick in quicker. I have even (laugh it up lead feet) started up and rollled backwards, and did a really slow J-turn and fluidly turned 180 degrees and pulled away downhill up to 20mpg with out ever hitting the gas (because i have to park on the other side of the street facing backwards to my route). I even pull away in parking lots (very flat or slight downhill) after a cold start-up with out ever hitting the gas up to 20mph. Just another trick i have learned.

 

Doesn't the turbo motor have an air pump? I thought I remember reading that it does. That would account for the loud noise on cold startup as well.