MINI2

Tigger, Eeyore & Roo · Dec 15th, 2007, 07:35 AM

Here's a basic question: why does the supercharger whine?

I'd always thought it was the belt whining, but last night while I was giving a friend a lift we were talking about it and realised that the supercharger can be pretty much silent at any engine speed; it's only when it's under load that it makes its glorious whining noise

For instance, the engine can sit at any constant engine speed (2, 3, 4 , 5 , 6,000 rpm) and the supercharger makes no noise. Put the gearbox into neutral and rev the engine to the rev line and, again, the supercharger makes no (or very little noise) noise. Yet, put the engine under load, accelerate hard and it whines like mad

Why is this?

Tigger.

MINI-Bob · Dec 15th, 2007, 01:11 PM

Good question, i'd assume it has something to do with the volume of air being forced through.

Tigger, Eeyore & Roo · Dec 15th, 2007, 01:13 PM

Okay, that means there's two of us who'd like to know!

Anyone?

Tigger.

Nebdingo · Dec 15th, 2007, 01:17 PM

Its cos its female...

When I stand on the wife and press harder she makes the same noise!

*hides from the missus!

Tigger, Eeyore & Roo · Dec 15th, 2007, 01:27 PM

LOL

I'm so glad I'm not in your shoes!

MINI-Bob · Dec 15th, 2007, 01:52 PM

I've been thinking about this some more.

What sort of 'charger does the MCS have? Don't think it will make any difference as they all whine! But i don't know.

Does the 'charger have a clutch which only engages when on full throttle so in effect it's not engaged at at lighter throttle and therefore doesn't whine?

Tigger, Eeyore & Roo · Dec 15th, 2007, 02:10 PM

No, the supercharger is "always on", but it only seems to whine loudly when under load

MINI-Bob · Dec 15th, 2007, 02:37 PM

Agreed!

Hope someone knows the answer!

richg40 · Dec 15th, 2007, 04:26 PM

The Eaton supercharger whines because the two bladed shafts are driven by straight cut toothed gears.

Loui · Dec 15th, 2007, 04:54 PM

Quote: Originally Posted by MINI-Bob (original)

I've been thinking about this some more.

What sort of 'charger does the MCS have? Don't think it will make any difference as they all whine! But i don't know.

Does the 'charger have a clutch which only engages when on full throttle so in effect it's not engaged at at lighter throttle and therefore doesn't whine?

Rotrex blowers dont whine

MINI-Bob · Dec 15th, 2007, 06:07 PM

So the MINI has an Eaton blower, which has straight cut gears which creates the whine. Yes?

So why doesn't it whine at small throttle openings?

richg40 · Dec 16th, 2007, 10:05 AM

there is less pessure on the bladestherefore gears, just like a straight cut gearbox whines less on overrun.

MINI-Bob · Dec 16th, 2007, 10:25 AM

Ok. That makes sense. Cheers

Tigger, Eeyore & Roo · Dec 16th, 2007, 12:29 PM

I'll buy that as well. Thanks.

Tigger.

r1_kde · Dec 17th, 2007, 12:02 PM

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.

Tigger, Eeyore & Roo · Dec 17th, 2007, 03:38 PM

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 · Dec 17th, 2007, 07:29 PM

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 · Dec 17th, 2007, 08:39 PM

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 · Dec 17th, 2007, 08:52 PM

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 · Dec 17th, 2007, 09:23 PM

Great, love the video

Just like the MCS, but much louder!

Tigger.

Dec 15th, 2007, 07:35 AM	#1
Tigger, Eeyore & Roo May '08: Bye bye Mini2... My Classifieds Join Date: May 2004 Location: Kernow, near England Local Time: 12:03 PM Posts: 4,512 Offline	Basic Question Time: Why does the supercharger whine? Here's a basic question: why does the supercharger whine? I'd always thought it was the belt whining, but last night while I was giving a friend a lift we were talking about it and realised that the supercharger can be pretty much silent at any engine speed; it's only when it's under load that it makes its glorious whining noise For instance, the engine can sit at any constant engine speed (2, 3, 4 , 5 , 6,000 rpm) and the supercharger makes no noise. Put the gearbox into neutral and rev the engine to the rev line and, again, the supercharger makes no (or very little noise) noise. Yet, put the engine under load, accelerate hard and it whines like mad Why is this? Tigger. May 08: Thanks to all of my friends on Mini2 for a lot of great times over the last 4 years. In future I can always be contacted here!

Dec 15th, 2007, 01:13 PM	#3 (permalink)
Tigger, Eeyore & Roo May '08: Bye bye Mini2... My Classifieds Join Date: May 2004 Location: Kernow, near England Local Time: 12:03 PM Posts: 4,512 Offline	Okay, that means there's two of us who'd like to know! Anyone? Tigger. May 08: Thanks to all of my friends on Mini2 for a lot of great times over the last 4 years. In future I can always be contacted here!

Dec 15th, 2007, 01:27 PM	#5 (permalink)
Tigger, Eeyore & Roo May '08: Bye bye Mini2... My Classifieds Join Date: May 2004 Location: Kernow, near England Local Time: 12:03 PM Posts: 4,512 Offline	LOL I'm so glad I'm not in your shoes! May 08: Thanks to all of my friends on Mini2 for a lot of great times over the last 4 years. In future I can always be contacted here!

Dec 15th, 2007, 02:10 PM	#7 (permalink)
Tigger, Eeyore & Roo May '08: Bye bye Mini2... My Classifieds Join Date: May 2004 Location: Kernow, near England Local Time: 12:03 PM Posts: 4,512 Offline	No, the supercharger is "always on", but it only seems to whine loudly when under load May 08: Thanks to all of my friends on Mini2 for a lot of great times over the last 4 years. In future I can always be contacted here!

Dec 15th, 2007, 04:26 PM	#9 (permalink)
richg40 MINI2 Regular Join Date: Sep 2007 Local Time: 12:03 PM Posts: 102 Offline	The Eaton supercharger whines because the two bladed shafts are driven by straight cut toothed gears. Everyone else is lying to you. stop giving out duff advice people!

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Dec 15th, 2007, 01:11 PM	#2 (permalink)
MINI-Bob I want that one! Join Date: Nov 2007 Location: Ont 'thmoors Local Time: 12:03 PM Posts: 126 Offline	Good question, i'd assume it has something to do with the volume of air being forced through.

Dec 15th, 2007, 01:17 PM	#4 (permalink)
Nebdingo ProNet:3 Gaming Community Join Date: Sep 2007 Location: Leicester UK Local Time: 12:03 PM Posts: 272 Offline	Its cos its female... When I stand on the wife and press harder she makes the same noise! *hides from the missus!

Dec 15th, 2007, 01:52 PM	#6 (permalink)
MINI-Bob I want that one! Join Date: Nov 2007 Location: Ont 'thmoors Local Time: 12:03 PM Posts: 126 Offline	I've been thinking about this some more. What sort of 'charger does the MCS have? Don't think it will make any difference as they all whine! But i don't know. Does the 'charger have a clutch which only engages when on full throttle so in effect it's not engaged at at lighter throttle and therefore doesn't whine?

Dec 15th, 2007, 02:37 PM	#8 (permalink)
MINI-Bob I want that one! Join Date: Nov 2007 Location: Ont 'thmoors Local Time: 12:03 PM Posts: 126 Offline	Agreed! Hope someone knows the answer!

Dec 15th, 2007, 04:54 PM	#10 (permalink)
Loui 230whp an counting My Classifieds Join Date: May 2002 Location: Mini Addiction Local Time: 12:03 PM Posts: 3,153 Offline	Quote: Originally Posted by MINI-Bob (original) I've been thinking about this some more. What sort of 'charger does the MCS have? Don't think it will make any difference as they all whine! But i don't know. Does the 'charger have a clutch which only engages when on full throttle so in effect it's not engaged at at lighter throttle and therefore doesn't whine? Rotrex blowers dont whine WWW.MINIADDICTION.CO.UK

Dec 15th, 2007, 06:07 PM	#11 (permalink)
MINI-Bob I want that one! Join Date: Nov 2007 Location: Ont 'thmoors Local Time: 12:03 PM Posts: 126 Offline	So the MINI has an Eaton blower, which has straight cut gears which creates the whine. Yes? So why doesn't it whine at small throttle openings?

Dec 16th, 2007, 10:05 AM	#12 (permalink)
richg40 MINI2 Regular Join Date: Sep 2007 Local Time: 12:03 PM Posts: 102 Offline	there is less pessure on the bladestherefore gears, just like a straight cut gearbox whines less on overrun. Everyone else is lying to you. stop giving out duff advice people!

Dec 16th, 2007, 10:25 AM	#13 (permalink)
MINI-Bob I want that one! Join Date: Nov 2007 Location: Ont 'thmoors Local Time: 12:03 PM Posts: 126 Offline	Ok. That makes sense. Cheers

Dec 16th, 2007, 12:29 PM	#14 (permalink)
Tigger, Eeyore & Roo May '08: Bye bye Mini2... My Classifieds Join Date: May 2004 Location: Kernow, near England Local Time: 12:03 PM Posts: 4,512 Offline	I'll buy that as well. Thanks. Tigger. May 08: Thanks to all of my friends on Mini2 for a lot of great times over the last 4 years. In future I can always be contacted here!

Dec 17th, 2007, 12:02 PM	#15 (permalink)
r1_kde JCW 210 "apparently" Join Date: Feb 2007 Local Time: 12:03 PM Posts: 240 Offline	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.

Dec 17th, 2007, 03:38 PM	#16 (permalink)
Tigger, Eeyore & Roo May '08: Bye bye Mini2... My Classifieds Join Date: May 2004 Location: Kernow, near England Local Time: 12:03 PM Posts: 4,512 Offline	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. May 08: Thanks to all of my friends on Mini2 for a lot of great times over the last 4 years. In future I can always be contacted here!

Dec 17th, 2007, 07:29 PM	#17 (permalink)
MINI-Bob I want that one! Join Date: Nov 2007 Location: Ont 'thmoors Local Time: 12:03 PM Posts: 126 Offline	Interesting read that. Think until someone has a definitive answer to what type of s/c the MINI uses, we're a bit stuck.

Dec 17th, 2007, 08:39 PM	#18 (permalink)
Tigger, Eeyore & Roo May '08: Bye bye Mini2... My Classifieds Join Date: May 2004 Location: Kernow, near England Local Time: 12:03 PM Posts: 4,512 Offline	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 May 08: Thanks to all of my friends on Mini2 for a lot of great times over the last 4 years. In future I can always be contacted here!

Dec 17th, 2007, 08:52 PM	#19 (permalink)
r1_kde JCW 210 "apparently" Join Date: Feb 2007 Local Time: 12:03 PM Posts: 240 Offline	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

Dec 17th, 2007, 09:23 PM	#20 (permalink)
Tigger, Eeyore & Roo May '08: Bye bye Mini2... My Classifieds Join Date: May 2004 Location: Kernow, near England Local Time: 12:03 PM Posts: 4,512 Offline	Great, love the video Just like the MCS, but much louder! Tigger. May 08: Thanks to all of my friends on Mini2 for a lot of great times over the last 4 years. In future I can always be contacted here!

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