Basic Question Time: Why does the supercharger whine?

[Tigger, Eeyore & Roo]

Read that.

Interesting though, because the article describes the twin screw and centrifugal supercharger as whining, but not the Roots (which, I believe, is the one that the MCS uses)

And, if it isn't anything to do with straight cut gears, why does it seem to be most related to engine load, rather than engine speed?

It seems to have been blown wide open again...

Tigger.

[MINI-Bob]

Interesting read that.

Think until someone has a definitive answer to what type of s/c the MINI uses, we're a bit stuck.

[Tigger, Eeyore & Roo]

It's definitely not the centrifuge type. I've heard it referred to as a Roots type, but when I say one it looked like something half way between the Roots and the twin screw type

[r1_kde]

Its 100% a roots blower. The reason it gets louder under load is "A" your opening the throttle and letting more air in which creates compression of air, hence this makes the rotors hot and they mesh more. "B" The sound carries back through the throttle and air filter which almost amplifies the sound. When you change to a cold cone intake the sound is louder, its down to the design of the cone and the sound insulating properties.

I own a celica 1zzfe which I have custom built an M45 blower on. Attached is the celica running NA with the blower turning, this is what your blower would sound like if it was only turning and not connected to your engine. This was fecking loud.

P1000045.flv - Video - Photobucket - Video and Image Hosting

Also just to show the engine as almost complete.




Just turning the blower over with your hand creates a whine as the lobes mesh! then when the expand they become louder and louder. Also worth nothing that the sound will find a way out. Hope this helps

[Tigger, Eeyore & Roo]

Great, love the video Just like the MCS, but much louder!

Tigger.

[jckf965]

I'm new to minis, I just bought a cooper works, and I'm curious why the engine makes whine after I shut down the car

[Posts001]

I Believe that the Cooper S uses a "positive displacement supercharger" rather than a "Cencentrifugal-type supercharger"

and I was told that the whine is the air particles hitting the impeller inside the Supercharger housing, and this creates the amazing whining sound

Please correct me if I am wrong

[hollinshead]

Quote: Originally Posted by r1_kde (original)

The superchargers whine because of the rotors meshing, as the tolerances are so close to ensure there is air pressure held, the rotors make a whine towards higer spreeds. Should you ever have the blower out of the car and turn by hand you will hear the sound of the rotors meshing. produces a sound like gears but it is the rotors just about touching, pre face lift should be louder at high speeds due to the lack of teflon coating.

Howstuffworks "Supercharger Basics"

Read the page, it helps with the basics.

Does this mean the only difference between the SC fitted to the facelift R53 and the Works one, is the size of the pulley?

[onecleverdude]

only whines under load?
the answer is in the question.

load.
larger throttle opening

exposes more air to the rotors
more work= more noise

[Tigger, Eeyore & Roo]

Hey, I asked that question over 3 1/2 years ago!

One thing I did learn later on is that the air box really muffles the noise the rotor blades make! A decent induction kit not only improves the performance, but really lets you hear the supercharger working