BICYCLE JACK

I know my supercharger must be engaging, but I don't know when. At times I know, because of the insane rush of speed. But when does the clutch hoop-up? I don't hear any clicks or cherps that some have posted. I have had cars in the past with boost gauges, but miss knowing. People have also posted that when an AMG engine first startes cold, the whine heard, is the supercharger. This must be wrong. no designer would engage a clutch and spin a compressor just as an engine is starting. My BMW has the same sound and its' naturaly asperated. The AMG is a" as needed" system thats' why it has a clutch, right? I see the traction control light often, why not a boost light? My E-55 2006 wagon has 48k. Thanks for your incite!

NDF55

I have been trying to figure out what that whining noise is when you start the car as well. Some say it's the supercharger but like you said that doesn't make sense. I even brought it to the dealership thinking it may be a bad pulley. They said "it's normal" anyone have any ideas?

Yacht Master

The wine is the super charger freewheeling. The clutch is only half of the system, there is also a blower bypass valve. When the car starts the SC is off and the bypass open what you hear is the belt and small parasitic drag in the clutch turning the SC and the vacuum of the engine also helps to rotate the SC. No boost is being produced even though the SC is rotating. It sounds like a power steering pump on it's last leg.

NDF55

Thank you Yacht Master. I've asked this question many times, yours is the first answer that actually makes sense.

BICYCLE JACK

I don't agree, my BMW has exact sound without a SC. Both engines us an air pump: Not my words::: This is an electrically driven pump that injects air into the exhaust stream to help complete the combustion of excess fuel during rich mixture conditions (cold start-up), and as a result also helps the catalytic converter warm-up sooner and work more effectively. Many other cars have been fitted with similar smog air pumps since the 1970s, but they were belt-driven instead of electric/computer controlled.

redlineAMG

That is correct. it is the electric air pump. sounds kinda like a turbo whine. many cars have them nowadays instead of a belt driven air pump like in the old days.

mikekuriger

all mercedes have the whine. it's just the smog pump.

emoving

Way to bring one back from the dead!

pearlpower

Whine is still there if you remove the SC belt.

mikekuriger

well, if you remove the smog pump, the whine will go away.