I wish I could hear the turbo spooling in my 240D, but it sounds like it's not there at all
The CDI's are so quiet, you can barely hear the engine, but the turbo sound seems to be quite noticeable, particularly on the Sprinters. I've never been able to hear the turbo whine on any of the IDI Mercedes turbodiesels except when the exhaust or intake have been modified (i.e. K&N filter and/or straight pipe exhaust). I've always wondered if that was an intentional design feature as the whine was an "undesirable" noise for most people.