Turbo whine down???

[Z4Rick]

Do you guys experiance a faint sound of your turbo whining down after a hard run when you shut it down?

It is intermittent on my Z, but noticable best after a hot lap upon pitting. Not troubling particularly, but much like you might expect after its been spooled up pretty good and it lasts only a few seconds. I can't imagine it is anything else I'm hearing....

 

[Smartbear]

You sure it's not the water pump? They're electric on these cars & run independent of the engine being turned off.
Especially after it's been given a good larraping as you mentioned
Rob

 

[Z4Rick]

No! I am not sure its the turbo! But is sounds just like a jet engine spooling down, and I can't imagine a water pump would sound like that. High pitch but muted, 3-7 seconds to disappear, I just assumed the turbo from the sound, but I guess the water pump might be the issue. If its the turbo, it will fail for sure on April 18 - one day after the warranty expires. Guess I'll wait and see! Thanks Rob.

 

[Ducklakeview]

A turbo should be pretty much silent when slowing down, and especially after a run hard I always let the engine idle for a minute or two. This allows the oil to cool the turbo somewhat, prolonging it's life.

Might seem a daft question, but you aren't blipping the throttle before turning off the engine are you? Doing that is BAD news for a turbo, and will shorten it's life drastically. The shaft between the two impellers pretty much floats on a film of oil, shutting down an engine that is above idle will disrupt that oil film...

Mike

 

[Z4Rick]

No I don't play with the throttle at shutdown at all and generally let it idle after a quick run. The exception is a series of time runs with a coach or an instructor watching from a tower near the pit area, so de-briefing happens quickly, hence the occasional quick shutdowns. That has been
when I have noticed the whine. Are there any other free spooling components under the E89 hood - perhaps some sort of mass air sensor or emissions control device?

 

[extaz]

There have been some posts here in the USA about sounds like that. They emanate more from the rear of the car and sometimes happen right after hard driving. Most believe it is from the electric fuel pump in the fuel tank and possibly some starvation from hard cornering. Maybe keeping more fuel in the tank would help?
By the way my Z3 suffered from oil starvation when auto-crossing and my older M3 did as well.

Happy New Year to All

 

[Smartbear]

No I don't play with the throttle at shutdown at all and generally let it idle after a quick run. The exception is a series of time runs with a coach or an instructor watching from a tower near the pit area, so de-briefing happens quickly, hence the occasional quick shutdowns. That has been
when I have noticed the whine. Are there any other free spooling components under the E89 hood - perhaps some sort of mass air sensor or emissions control device?

Hi, because there's not so much engine vacuum on cars with valvetronic I think an air pump is utilised which sounds like a winding down spooling noise
Rob

 

[Z4Rick]

No I don't play with the throttle at shutdown at all and generally let it idle after a quick run. The exception is a series of time runs with a coach or an instructor watching from a tower near the pit area, so de-briefing happens quickly, hence the occasional quick shutdowns. That has been
when I have noticed the whine. Are there any other free spooling components under the E89 hood - perhaps some sort of mass air sensor or emissions control device?

Hi, because there's not so much engine vacuum on cars with valvetronic I think an air pump is utilised which sounds like a winding down spooling noise
Rob

THAT sounds like a possible culprit and moves to the top of the list....Good Call! Might be the plumbing too.....I'll nose around it tomorrow.