Some timie ago I posted a question, no takers, on how I could reduce a low-frequency drone I am getting. I've replaced everything from the exhaust manifold gaskets through to the tailpipe (Borla, whose website says they specifically "design out" low-frequency noise), and I still get it at 2,000 rpm and above, in any gear.

Eventually I came across this quote on another car board: "Air intake drone will increase (this is an annoying low frequency noise that appears with heavy throttle at low rpm)."

Does the Volvo world recognize "air intake drone?"

Is there any way to stop it? I love my 740, which would cruise like a dream if it didn't do this to me.

Maybe add a second air box with filter to split the load coming in? Would this upset the vacuum conditions at the AMM and/or elsewhere in the intake system. Would "upsetting" it have any bad consequences?

Any ideas?

Andy Crosby (also have an '85 240 -- no drone)