'88 930: fluttering & gasping noise under boost
05-27-2024, 03:14 PM
#1
'88 930: fluttering & gasping noise under boost
Car is my friend's '88 830. At 3500 rpm full boost, it's making fluttering / surging / gasping noises. It's fine at sea level.
See attached clip. Sounds like compressor surge and/or the bypass valve periodically venting and/or overboost protection intervening. The boost goes to 1.0 bar on the stock dash gauge and oscillates slightly during this.
It has a Fabspeed K27 and long-neck intercooler. I believe this intercooler deletes the clunky stock air bypass system with the later simpler one.
What's the root cause?
See attached clip. Sounds like compressor surge and/or the bypass valve periodically venting and/or overboost protection intervening. The boost goes to 1.0 bar on the stock dash gauge and oscillates slightly during this.
It has a Fabspeed K27 and long-neck intercooler. I believe this intercooler deletes the clunky stock air bypass system with the later simpler one.
What's the root cause?
