MINI2

gvl · Aug 20th, 2002, 06:32 AM

Just wondering....

Seeing lots of threads about power-loss if A/C is turned on:

The A/C compressor must be connected to the engine in some way...

If one turns the A/C to off, how does this effect the connection? Isn't it so that the physical connection will stay there allways having influence

Ger

cleverzippy · Aug 20th, 2002, 08:12 AM

The A/C compressor is connected via an electric clutch which engages when you push the switch.

gvl · Aug 20th, 2002, 11:49 AM

Quote:

Originally posted by cleverzippy
The A/C compressor is connected via an electric clutch which engages when you push the switch.

Well, that is clever-zippy...

So it does make the difference.

btw: is there always such a clutch in A/C systems?
(f.i. on my Passat 1.8 Turbo?)

Thanks

Ger

M3NTAL Kev · Aug 20th, 2002, 12:14 PM

Quote:

Originally posted by gvl

btw: is there always such a clutch in A/C systems?
(f.i. on my Passat 1.8 Turbo?)

Yup.

chiph · Aug 20th, 2002, 02:13 PM

Yeah, the compressor typically stays engaged until the expansion unit (up under the dash) has dropped to 40F (4C) or so. The electromagnetic clutch then opens until the temperature in the expansion unit has risen enough to require it to be engaged again. There are some other conditions which affect compressor operation - one is that it'll disengage at wide-open-throttle (at least on other cars I've had - I assume the MINI is the same).

When the compressor is engaged, the drive-by-wire throttle is supposed to supply more gas to the engine, so that the idle stays where it's supposed to. You'll still have a power loss because the compressor does consume horsepower, but it's much less than in cars past. When I had my college car, I'd refer to the A/C switch as the "turbo boost" (i.e. switching it off made the car much faster).

Chip H.

HarryHBMCC · Aug 20th, 2002, 03:08 PM

It sounds like the FBW throttle doesn't work then as it takes more gas to get moving with the AC on in hot weather. If you just give it normal gas and clutch then the revs drop instead of increasing, possibly even stalling. See the thread in faults...

It is interesting that it takes less load when it isn't that warm out. I turn it on to help defog the windows and cool rainy days don't affect the performance much but hot sweltering days need a bit of a clutch dump.

Harry

cleverzippy · Aug 20th, 2002, 04:31 PM

Quote:

Originally posted by HarryIndiBlue
It sounds like the FBW throttle doesn't work then as it takes more gas to get moving with the AC on in hot weather. If you just give it normal gas and clutch then the revs drop instead of increasing, possibly even stalling. See the thread in faults...

It is interesting that it takes less load when it isn't that warm out. I turn it on to help defog the windows and cool rainy days don't affect the performance much but hot sweltering days need a bit of a clutch dump.

Harry

Could be due to the fact that you get more power on a cool, damp day and less when it's hot. I noticed this a few days ago when it was 30c (yes, really!) and the power decrease was quite noticeable. Especially when you consider the puny size of the intercooler. Should be much bigger. (JCW, maybe??)

Bilbo Baggins · Aug 20th, 2002, 09:26 PM

I am hoping that since it is a FBW throttle that there might be a software patch coming that will solve the boggy launch problem when the AC is on. It shouldn't be all that difficult, are you listening MINIUK? and MINIUSA?

Aug 20th, 2002, 06:32 AM	#1
gvl MINI2 Regular Join Date: Jun 2002 Location: Netherland-S Local Time: 12:20 AM Posts: 231 Offline	Is the AC alway connected? Just wondering.... Seeing lots of threads about power-loss if A/C is turned on: The A/C compressor must be connected to the engine in some way... If one turns the A/C to off, how does this effect the connection? Isn't it so that the physical connection will stay there allways having influence Ger

Aug 20th, 2002, 02:13 PM	#5 (permalink)
chiph Spectator Join Date: Feb 2002 Location: Raleigh, NC Local Time: 06:20 PM Posts: 1,574 Offline	Yeah, the compressor typically stays engaged until the expansion unit (up under the dash) has dropped to 40F (4C) or so. The electromagnetic clutch then opens until the temperature in the expansion unit has risen enough to require it to be engaged again. There are some other conditions which affect compressor operation - one is that it'll disengage at wide-open-throttle (at least on other cars I've had - I assume the MINI is the same). When the compressor is engaged, the drive-by-wire throttle is supposed to supply more gas to the engine, so that the idle stays where it's supposed to. You'll still have a power loss because the compressor does consume horsepower, but it's much less than in cars past. When I had my college car, I'd refer to the A/C switch as the "turbo boost" (i.e. switching it off made the car much faster). Chip H. ex-MINI Cooper S owner and all around good-guy

Aug 20th, 2002, 03:08 PM	#6 (permalink)
HarryHBMCC MINI2 Master Join Date: Apr 2002 Location: Guelph, Ontario, Can Local Time: 05:20 PM Posts: 2,686 Offline	It sounds like the FBW throttle doesn't work then as it takes more gas to get moving with the AC on in hot weather. If you just give it normal gas and clutch then the revs drop instead of increasing, possibly even stalling. See the thread in faults... It is interesting that it takes less load when it isn't that warm out. I turn it on to help defog the windows and cool rainy days don't affect the performance much but hot sweltering days need a bit of a clutch dump. Harry MINI Cooper Cabrio: now the car with go cart handling really feels like an open go cart! "... the only man that can come home at 3 am in the morning without getting into trouble with his spouse is the owner of a British sports car!" -- Phil Bailey

Aug 20th, 2002, 09:26 PM	#8 (permalink)
Bilbo Baggins MINI2 Master Join Date: Oct 2001 Location: Shire, Middle Earth Local Time: 06:20 PM Posts: 8,854 Offline	I am hoping that since it is a FBW throttle that there might be a software patch coming that will solve the boggy launch problem when the AC is on. It shouldn't be all that difficult, are you listening MINIUK? and MINIUSA? Motor on, Dudes and Dudettes!!! '06 MCS SB/S '02 MCS DS/W (retired)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Rate This Thread
Rate This Thread:

MINI2

Fuel for your MINI obsession

From air-filters to exhausts and all in between, discuss them here

Today
Sponsors	Sponsored Links Registered members do not see Google Ads posts, they can also post messages, pictures, and classified adverts. Register your free account today and become a member of MINI2 - MINI Forum

Aug 20th, 2002, 08:12 AM	#2 (permalink)
cleverzippy MINI2 Regular Join Date: Apr 2002 Location: Kettering, Northants Local Time: 11:20 PM Posts: 185 Offline	The A/C compressor is connected via an electric clutch which engages when you push the switch.

Aug 20th, 2002, 11:49 AM	#3 (permalink)
gvl MINI2 Regular Join Date: Jun 2002 Location: Netherland-S Local Time: 12:20 AM Posts: 231 Offline	Quote: Originally posted by cleverzippy The A/C compressor is connected via an electric clutch which engages when you push the switch. Well, that is clever-zippy... So it does make the difference. btw: is there always such a clutch in A/C systems? (f.i. on my Passat 1.8 Turbo?) Thanks Ger

Aug 20th, 2002, 12:14 PM	#4 (permalink)
M3NTAL Kev MINI2 Regular Join Date: Jul 2002 Location: Toronto, ON Local Time: 06:20 PM Posts: 142 Offline	Quote: Originally posted by gvl btw: is there always such a clutch in A/C systems? (f.i. on my Passat 1.8 Turbo?) Yup.

Aug 20th, 2002, 04:31 PM	#7 (permalink)
cleverzippy MINI2 Regular Join Date: Apr 2002 Location: Kettering, Northants Local Time: 11:20 PM Posts: 185 Offline	Quote: Originally posted by HarryIndiBlue It sounds like the FBW throttle doesn't work then as it takes more gas to get moving with the AC on in hot weather. If you just give it normal gas and clutch then the revs drop instead of increasing, possibly even stalling. See the thread in faults... It is interesting that it takes less load when it isn't that warm out. I turn it on to help defog the windows and cool rainy days don't affect the performance much but hot sweltering days need a bit of a clutch dump. Harry Could be due to the fact that you get more power on a cool, damp day and less when it's hot. I noticed this a few days ago when it was 30c (yes, really!) and the power decrease was quite noticeable. Especially when you consider the puny size of the intercooler. Should be much bigger. (JCW, maybe??)

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Connected Lights in US spec Aero Kit ( Night picks added see post num 4)	KAS66	Exterior	6	Jul 11th, 2007 07:06 AM
BMW boost stereo not recognising cd player connected	anthony.manders	Interior & Ice	0	May 31st, 2006 07:09 AM
Where should the violet and red cable next to the cigarette lighter bew connected?	Mikel	Faults & Fixes	3	Jul 30th, 2004 09:15 AM