w116 300sd

[xaliscomex]

Own a 1979 300sd (w116) with 192,000 miles. Today I noticed this air gush noise that sounded much like "Air Bags" coming out of my car. My coworker parked next to me also heard the noise and rolled his window down and asked if the noise was coming out from my car or his car. I also heard the air release and suspected it was coming from my car. Just before I heard the air noise my car had been warming up for about a minute when I decided to floor it while in Park to get my friends attention and let him know that I was going to pull out of the parking lot first. 2 days ago I thought I heard a very similar noise coming out of my car but I figured it was a car driving on the opposite side of the road. I dismissed the noise and continued driving. 2 weeks ago I came to a stop and then immediately floored it and noticed that the car was getting louder and reving higher but not increasing in velocity. It was a weird feeling to the car and had never experienced that build in pressure without having some kind of increase in speed. I thought it might have been the tranny but did not feel an ounce of worry because the tranny shifted normal like always and have not felt any problems in the tranny shifting since. I thought it could of been the turbo spooling to quickly and somehow not responding due to some kind of protection mechanism. What could make this "Air Bag" air release noise. Its very loud. The only other thing i could think about was something vacuum related. Has anyone experienced this?
      

[JasonP]

Just out of reading your post, I would say to look closely (visual inspection) around your turbo, exhaust, and intake systems. It reads like you have a simple hole somewhere in your engine air system.